From 84418c7dd384e9b3e42a2c43f4823ff4816e634e Mon Sep 17 00:00:00 2001
From: Shivam Goyal <shivgo@iitk.ac.in>
Date: Sun, 24 Mar 2019 16:19:05 +0530
Subject: [PATCH] Added XV file support

---
 libavformat/Makefile     |    1 +
 libavformat/allformats.c |    1 +
 libavformat/xvdec.c      | 1395 ++++++++++++++++++++++++++++++++++++++
 libavformat/xvtools.h    |   95 +++
 4 files changed, 1492 insertions(+)
 create mode 100644 libavformat/xvdec.c
 create mode 100644 libavformat/xvtools.h

diff --git a/libavformat/Makefile b/libavformat/Makefile
index c010fc83f9..9fc1288ed3 100644
--- a/libavformat/Makefile
+++ b/libavformat/Makefile
@@ -187,6 +187,7 @@ OBJS-$(CONFIG_FLAC_MUXER)                += flacenc.o flacenc_header.o \
                                             vorbiscomment.o
 OBJS-$(CONFIG_FLIC_DEMUXER)              += flic.o
 OBJS-$(CONFIG_FLV_DEMUXER)               += flvdec.o
+OBJS-$(CONFIG_XV_DEMUXER)                += xvdec.o
 OBJS-$(CONFIG_LIVE_FLV_DEMUXER)          += flvdec.o
 OBJS-$(CONFIG_FLV_MUXER)                 += flvenc.o avc.o
 OBJS-$(CONFIG_FOURXM_DEMUXER)            += 4xm.o
diff --git a/libavformat/allformats.c b/libavformat/allformats.c
index 73d69cda99..7a6a26328f 100644
--- a/libavformat/allformats.c
+++ b/libavformat/allformats.c
@@ -144,6 +144,7 @@ extern AVInputFormat  ff_flac_demuxer;
 extern AVOutputFormat ff_flac_muxer;
 extern AVInputFormat  ff_flic_demuxer;
 extern AVInputFormat  ff_flv_demuxer;
+extern AVInputFormat  ff_xv_demuxer;
 extern AVOutputFormat ff_flv_muxer;
 extern AVInputFormat  ff_live_flv_demuxer;
 extern AVInputFormat  ff_fourxm_demuxer;
diff --git a/libavformat/xvdec.c b/libavformat/xvdec.c
new file mode 100644
index 0000000000..70683635b3
--- /dev/null
+++ b/libavformat/xvdec.c
@@ -0,0 +1,1395 @@
+// /*
+//  * XV demuxer
+//  * Copyright (c) 2003 The FFmpeg Project
+//  *
+//  * This demuxer will generate a 1 byte extradata for VP6F content.
+//  * It is composed of:
+//  *  - upper 4 bits: difference between encoded width and visible width
+//  *  - lower 4 bits: difference between encoded height and visible height
+//  *
+//  * This file is part of FFmpeg.
+//  *
+//  * FFmpeg is free software; you can redistribute it and/or
+//  * modify it under the terms of the GNU Lesser General Public
+//  * License as published by the Free Software Foundation; either
+//  * version 2.1 of the License, or (at your option) any later version.
+//  *
+//  * FFmpeg is distributed in the hope that it will be useful,
+//  * but WITHOUT ANY WARRANTY; without even the implied warranty of
+//  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+//  * Lesser General Public License for more details.
+//  *
+//  * You should have received a copy of the GNU Lesser General Public
+//  * License along with FFmpeg; if not, write to the Free Software
+//  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+//  */
+
+#include "libavutil/avstring.h"
+#include "libavutil/channel_layout.h"
+#include "libavutil/dict.h"
+#include "libavutil/opt.h"
+#include "libavutil/intfloat.h"
+#include "libavutil/mathematics.h"
+#include "libavcodec/bytestream.h"
+#include "libavcodec/mpeg4audio.h"
+#include "avformat.h"
+#include "internal.h"
+#include "avio_internal.h"
+#include "flv.h"
+#include "xvtools.h"
+#define VALIDATE_INDEX_TS_THRESH 2500
+
+#define RESYNC_BUFFER_SIZE (1<<20)
+
+typedef struct XVContext {
+    const AVClass *class; ///< Class for private options.
+    int trust_metadata;   ///< configure streams according onMetaData
+    int trust_datasize;   ///< trust data size of FLVTag
+    int dump_full_metadata;   ///< Dump full metadata of the onMetadata
+    int wrong_dts;        ///< wrong dts due to negative cts
+    uint8_t *new_extradata[FLV_STREAM_TYPE_NB];
+    int new_extradata_size[FLV_STREAM_TYPE_NB];
+    int last_sample_rate;
+    int last_channels;
+    struct {
+        int64_t dts;
+        int64_t pos;
+    } validate_index[2];
+    int validate_next;
+    int validate_count;
+    int searched_for_end;
+
+    uint8_t resync_buffer[2*RESYNC_BUFFER_SIZE];
+
+    int broken_sizes;
+    int sum_flv_tag_size;
+
+    int last_keyframe_stream_index;
+    int keyframe_count;
+    int64_t video_bit_rate;
+    int64_t audio_bit_rate;
+    int64_t *keyframe_times;
+    int64_t *keyframe_filepositions;
+    int missing_streams;
+    AVRational framerate;
+    int64_t last_ts;
+    int64_t time_offset;
+    int64_t time_pos;
+    int rot_value; ///< The value by which some bytes are encrypted
+} XVContext;
+
+
+static int xv_probe(AVProbeData *p)
+{
+    const uint8_t *d = p->buf;
+    
+    if(d[0] == 'X' && d[1] == 'L' && d[2] == 'V' && d[3] =='F'){
+        return AVPROBE_SCORE_MAX;
+    }
+    
+    return 0;
+}
+
+static void add_keyframes_index(AVFormatContext *s)
+{
+    XVContext *xv   = s->priv_data;
+    AVStream *stream  = NULL;
+    unsigned int i    = 0;
+
+    if (xv->last_keyframe_stream_index < 0) {
+        av_log(s, AV_LOG_DEBUG, "keyframe stream hasn't been created\n");
+        return;
+    }
+
+    av_assert0(xv->last_keyframe_stream_index <= s->nb_streams);
+    stream = s->streams[xv->last_keyframe_stream_index];
+
+    if (stream->nb_index_entries == 0) {
+        for (i = 0; i < xv->keyframe_count; i++) {
+            av_log(s, AV_LOG_TRACE, "keyframe filepositions = %"PRId64" times = %"PRId64"\n",
+                   xv->keyframe_filepositions[i], xv->keyframe_times[i] * 1000);
+            av_add_index_entry(stream, xv->keyframe_filepositions[i],
+                xv->keyframe_times[i] * 1000, 0, 0, AVINDEX_KEYFRAME);
+        }
+    } else
+        av_log(s, AV_LOG_WARNING, "Skipping duplicate index\n");
+
+    if (stream->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
+        av_freep(&xv->keyframe_times);
+        av_freep(&xv->keyframe_filepositions);
+        xv->keyframe_count = 0;
+    }
+}
+
+static AVStream *create_stream(AVFormatContext *s, int codec_type)
+{
+    XVContext *xv   = s->priv_data;
+    AVStream *st = avformat_new_stream(s, NULL);
+    if (!st)
+        return NULL;
+    st->codecpar->codec_type = codec_type;
+    if (s->nb_streams>=3 ||(   s->nb_streams==2
+                           && s->streams[0]->codecpar->codec_type != AVMEDIA_TYPE_SUBTITLE
+                           && s->streams[1]->codecpar->codec_type != AVMEDIA_TYPE_SUBTITLE
+                           && s->streams[0]->codecpar->codec_type != AVMEDIA_TYPE_DATA
+                           && s->streams[1]->codecpar->codec_type != AVMEDIA_TYPE_DATA))
+        s->ctx_flags &= ~AVFMTCTX_NOHEADER;
+    if (codec_type == AVMEDIA_TYPE_AUDIO) {
+        st->codecpar->bit_rate = xv->audio_bit_rate;
+        xv->missing_streams &= ~FLV_HEADER_FLAG_HASAUDIO;
+    }
+    if (codec_type == AVMEDIA_TYPE_VIDEO) {
+        st->codecpar->bit_rate = xv->video_bit_rate;
+        xv->missing_streams &= ~FLV_HEADER_FLAG_HASVIDEO;
+        st->avg_frame_rate = xv->framerate;
+    }
+
+
+    avpriv_set_pts_info(st, 32, 1, 1000); /* 32 bit pts in ms */
+    xv->last_keyframe_stream_index = s->nb_streams - 1;
+    add_keyframes_index(s);
+    return st;
+}
+
+static int flv_same_audio_codec(AVCodecParameters *apar, int flags)
+{
+    int bits_per_coded_sample = (flags & FLV_AUDIO_SAMPLESIZE_MASK) ? 16 : 8;
+    int flv_codecid           = flags & FLV_AUDIO_CODECID_MASK;
+    int codec_id;
+
+    if (!apar->codec_id && !apar->codec_tag)
+        return 1;
+
+    if (apar->bits_per_coded_sample != bits_per_coded_sample)
+        return 0;
+
+    switch (flv_codecid) {
+    // no distinction between S16 and S8 PCM codec flags
+    case FLV_CODECID_PCM:
+        codec_id = bits_per_coded_sample == 8
+                   ? AV_CODEC_ID_PCM_U8
+#if HAVE_BIGENDIAN
+                   : AV_CODEC_ID_PCM_S16BE;
+#else
+                   : AV_CODEC_ID_PCM_S16LE;
+#endif
+        return codec_id == apar->codec_id;
+    case FLV_CODECID_PCM_LE:
+        codec_id = bits_per_coded_sample == 8
+                   ? AV_CODEC_ID_PCM_U8
+                   : AV_CODEC_ID_PCM_S16LE;
+        return codec_id == apar->codec_id;
+    case FLV_CODECID_AAC:
+        return apar->codec_id == AV_CODEC_ID_AAC;
+    case FLV_CODECID_ADPCM:
+        return apar->codec_id == AV_CODEC_ID_ADPCM_SWF;
+    case FLV_CODECID_SPEEX:
+        return apar->codec_id == AV_CODEC_ID_SPEEX;
+    case FLV_CODECID_MP3:
+        return apar->codec_id == AV_CODEC_ID_MP3;
+    case FLV_CODECID_NELLYMOSER_8KHZ_MONO:
+    case FLV_CODECID_NELLYMOSER_16KHZ_MONO:
+    case FLV_CODECID_NELLYMOSER:
+        return apar->codec_id == AV_CODEC_ID_NELLYMOSER;
+    case FLV_CODECID_PCM_MULAW:
+        return apar->sample_rate == 8000 &&
+               apar->codec_id    == AV_CODEC_ID_PCM_MULAW;
+    case FLV_CODECID_PCM_ALAW:
+        return apar->sample_rate == 8000 &&
+               apar->codec_id    == AV_CODEC_ID_PCM_ALAW;
+    default:
+        return apar->codec_tag == (flv_codecid >> FLV_AUDIO_CODECID_OFFSET);
+    }
+}
+
+static void xv_set_audio_codec(AVFormatContext *s, AVStream *astream,
+                                AVCodecParameters *apar, int flv_codecid)
+{
+    switch (flv_codecid) {
+    // no distinction between S16 and S8 PCM codec flags
+    case FLV_CODECID_PCM:
+        apar->codec_id = apar->bits_per_coded_sample == 8
+                           ? AV_CODEC_ID_PCM_U8
+#if HAVE_BIGENDIAN
+                           : AV_CODEC_ID_PCM_S16BE;
+#else
+                           : AV_CODEC_ID_PCM_S16LE;
+#endif
+        break;
+    case FLV_CODECID_PCM_LE:
+        apar->codec_id = apar->bits_per_coded_sample == 8
+                           ? AV_CODEC_ID_PCM_U8
+                           : AV_CODEC_ID_PCM_S16LE;
+        break;
+    case FLV_CODECID_AAC:
+        apar->codec_id = AV_CODEC_ID_AAC;
+        break;
+    case FLV_CODECID_ADPCM:
+        apar->codec_id = AV_CODEC_ID_ADPCM_SWF;
+        break;
+    case FLV_CODECID_SPEEX:
+        apar->codec_id    = AV_CODEC_ID_SPEEX;
+        apar->sample_rate = 16000;
+        break;
+    case FLV_CODECID_MP3:
+        apar->codec_id      = AV_CODEC_ID_MP3;
+        astream->need_parsing = AVSTREAM_PARSE_FULL;
+        break;
+    case FLV_CODECID_NELLYMOSER_8KHZ_MONO:
+        // in case metadata does not otherwise declare samplerate
+        apar->sample_rate = 8000;
+        apar->codec_id    = AV_CODEC_ID_NELLYMOSER;
+        break;
+    case FLV_CODECID_NELLYMOSER_16KHZ_MONO:
+        apar->sample_rate = 16000;
+        apar->codec_id    = AV_CODEC_ID_NELLYMOSER;
+        break;
+    case FLV_CODECID_NELLYMOSER:
+        apar->codec_id = AV_CODEC_ID_NELLYMOSER;
+        break;
+    case FLV_CODECID_PCM_MULAW:
+        apar->sample_rate = 8000;
+        apar->codec_id    = AV_CODEC_ID_PCM_MULAW;
+        break;
+    case FLV_CODECID_PCM_ALAW:
+        apar->sample_rate = 8000;
+        apar->codec_id    = AV_CODEC_ID_PCM_ALAW;
+        break;
+    default:
+        avpriv_request_sample(s, "Audio codec (%x)",
+               flv_codecid >> FLV_AUDIO_CODECID_OFFSET);
+        apar->codec_tag = flv_codecid >> FLV_AUDIO_CODECID_OFFSET;
+    }
+}
+
+static int flv_same_video_codec(AVCodecParameters *vpar, int flags)
+{
+    int flv_codecid = flags & FLV_VIDEO_CODECID_MASK;
+
+    if (!vpar->codec_id && !vpar->codec_tag)
+        return 1;
+
+    switch (flv_codecid) {
+    case FLV_CODECID_H263:
+        return vpar->codec_id == AV_CODEC_ID_FLV1;
+    case FLV_CODECID_SCREEN:
+        return vpar->codec_id == AV_CODEC_ID_FLASHSV;
+    case FLV_CODECID_SCREEN2:
+        return vpar->codec_id == AV_CODEC_ID_FLASHSV2;
+    case FLV_CODECID_VP6:
+        return vpar->codec_id == AV_CODEC_ID_VP6F;
+    case FLV_CODECID_VP6A:
+        return vpar->codec_id == AV_CODEC_ID_VP6A;
+    case FLV_CODECID_H264:
+        return vpar->codec_id == AV_CODEC_ID_H264;
+    default:
+        return vpar->codec_tag == flv_codecid;
+    }
+}
+
+static int xv_set_video_codec(AVFormatContext *s, AVStream *vstream,
+                               int flv_codecid, int read)
+{
+    int ret = 0;
+    AVCodecParameters *par = vstream->codecpar;
+    enum AVCodecID old_codec_id = vstream->codecpar->codec_id;
+    switch (flv_codecid) {
+    case FLV_CODECID_H263:
+        par->codec_id = AV_CODEC_ID_FLV1;
+        break;
+    case FLV_CODECID_REALH263:
+        par->codec_id = AV_CODEC_ID_H263;
+        break; // Really mean it this time
+    case FLV_CODECID_SCREEN:
+        par->codec_id = AV_CODEC_ID_FLASHSV;
+        break;
+    case FLV_CODECID_SCREEN2:
+        par->codec_id = AV_CODEC_ID_FLASHSV2;
+        break;
+    case FLV_CODECID_VP6:
+        par->codec_id = AV_CODEC_ID_VP6F;
+    case FLV_CODECID_VP6A:
+        if (flv_codecid == FLV_CODECID_VP6A)
+            par->codec_id = AV_CODEC_ID_VP6A;
+        if (read) {
+            if (par->extradata_size != 1) {
+                ff_alloc_extradata(par, 1);
+            }
+            if (par->extradata)
+                par->extradata[0] = avio_r8(s->pb);
+            else
+                avio_skip(s->pb, 1);
+        }
+        ret = 1;     // 1 byte body size adjustment for xv_read_packet()
+        break;
+    case FLV_CODECID_H264:
+        par->codec_id = AV_CODEC_ID_H264;
+        vstream->need_parsing = AVSTREAM_PARSE_HEADERS;
+        ret = 3;     // not 4, reading packet type will consume one byte
+        break;
+    case FLV_CODECID_MPEG4:
+        par->codec_id = AV_CODEC_ID_MPEG4;
+        ret = 3;
+        break;
+    default:
+        avpriv_request_sample(s, "Video codec (%x)", flv_codecid);
+        par->codec_tag = flv_codecid;
+    }
+
+    if (!vstream->internal->need_context_update && par->codec_id != old_codec_id) {
+        avpriv_request_sample(s, "Changing the codec id midstream");
+        return AVERROR_PATCHWELCOME;
+    }
+
+    return ret;
+}
+
+static int amf_get_string(AVIOContext *ioc, char *buffer, int buffsize, int rot)
+{
+
+    int length = xvio_rb16(ioc, rot);
+    if (length >= buffsize) {
+        avio_skip(ioc, length);
+        return -1;
+    }
+    int64_t curr_pos = avio_tell(ioc);
+    avio_read(ioc, buffer, length);
+
+    buffer[length] = '\0';
+    int ret = xv_string_decrypt(curr_pos, buffer, length, rot);
+    if(ret != 0){
+        return -1;
+    }
+    return length;
+}
+
+static int parse_keyframes_index(AVFormatContext *s, AVIOContext *ioc, int64_t max_pos)
+{
+    XVContext *xv       = s->priv_data;
+    unsigned int timeslen = 0, fileposlen = 0, i;
+    char str_val[256];
+    int64_t *times         = NULL;
+    int64_t *filepositions = NULL;
+    int ret                = AVERROR(ENOSYS);
+    int64_t initial_pos    = avio_tell(ioc);
+    int rot;
+    if(xv->rot_value){
+        rot=xv->rot_value;
+    }
+    else{
+        rot = find_rot(s->pb);
+        xv->rot_value = rot;
+    }
+
+    if (xv->keyframe_count > 0) {
+        av_log(s, AV_LOG_DEBUG, "keyframes have been paresed\n");
+        return 0;
+    }
+    av_assert0(!xv->keyframe_times);
+    av_assert0(!xv->keyframe_filepositions);
+
+    if (s->flags & AVFMT_FLAG_IGNIDX)
+        return 0;
+
+    while (avio_tell(ioc) < max_pos - 2 &&
+           amf_get_string(ioc, str_val, sizeof(str_val), rot) > 0) {
+        int64_t **current_array;
+        unsigned int arraylen;
+
+        // Expect array object in context
+        if (xvio_r8(ioc, rot) != AMF_DATA_TYPE_ARRAY)
+            break;
+
+        arraylen = xvio_rb32(ioc, rot);
+        if (arraylen>>28)
+            break;
+
+        if       (!strcmp(KEYFRAMES_TIMESTAMP_TAG , str_val) && !times) {
+            current_array = &times;
+            timeslen      = arraylen;
+        } else if (!strcmp(KEYFRAMES_BYTEOFFSET_TAG, str_val) &&
+                   !filepositions) {
+            current_array = &filepositions;
+            fileposlen    = arraylen;
+        } else
+            // unexpected metatag inside keyframes, will not use such
+            // metadata for indexing
+            break;
+
+        if (!(*current_array = av_mallocz(sizeof(**current_array) * arraylen))) {
+            ret = AVERROR(ENOMEM);
+            goto finish;
+        }
+
+        for (i = 0; i < arraylen && avio_tell(ioc) < max_pos - 1; i++) {
+            if (xvio_r8(ioc, rot) != AMF_DATA_TYPE_NUMBER)
+                goto invalid;
+            current_array[0][i] = av_int2double(xvio_rb64(ioc, rot));
+        }
+        if (times && filepositions) {
+            // All done, exiting at a position allowing amf_parse_object
+            // to finish parsing the object
+            ret = 0;
+            break;
+        }
+    }
+
+    if (timeslen == fileposlen && fileposlen>1 && max_pos <= filepositions[0]) {
+        for (i = 0; i < FFMIN(2,fileposlen); i++) {
+            xv->validate_index[i].pos = filepositions[i];
+            xv->validate_index[i].dts = times[i] * 1000;
+            xv->validate_count        = i + 1;
+        }
+        xv->keyframe_times = times;
+        xv->keyframe_filepositions = filepositions;
+        xv->keyframe_count = timeslen;
+        times = NULL;
+        filepositions = NULL;
+    } else {
+invalid:
+        av_log(s, AV_LOG_WARNING, "Invalid keyframes object, skipping.\n");
+    }
+
+finish:
+    av_freep(&times);
+    av_freep(&filepositions);
+    avio_seek(ioc, initial_pos, SEEK_SET);
+    return ret;
+}
+
+static int amf_parse_object(AVFormatContext *s, AVStream *astream,
+                            AVStream *vstream, const char *key,
+                            int64_t max_pos, int depth)
+{
+    AVCodecParameters *apar, *vpar;
+    XVContext *xv = s->priv_data;
+    AVIOContext *ioc;
+    AMFDataType amf_type;
+    char str_val[1024];
+    double num_val;
+    int rot;
+    if(xv->rot_value){
+        rot = xv->rot_value;
+    }
+    else{
+        rot = find_rot(s->pb);
+        xv->rot_value = rot;
+    }
+
+    num_val  = 0;
+    ioc      = s->pb;
+    amf_type = xvio_r8(ioc, rot);
+
+    switch (amf_type) {
+    case AMF_DATA_TYPE_NUMBER:
+        num_val = av_int2double(xvio_rb64(ioc, rot));
+        break;
+    case AMF_DATA_TYPE_BOOL:
+        num_val = xvio_r8(ioc, rot);
+        break;
+    case AMF_DATA_TYPE_STRING:
+        if (amf_get_string(ioc, str_val, sizeof(str_val), rot) < 0) {
+            av_log(s, AV_LOG_ERROR, "AMF_DATA_TYPE_STRING parsing failed\n");
+            return -1;
+        }
+        break;
+    case AMF_DATA_TYPE_OBJECT:
+        if (key &&
+            (ioc->seekable & AVIO_SEEKABLE_NORMAL) &&
+            !strcmp(KEYFRAMES_TAG, key) && depth == 1)
+            if (parse_keyframes_index(s, ioc,
+                                      max_pos) < 0)
+                av_log(s, AV_LOG_ERROR, "Keyframe index parsing failed\n");
+            else
+                add_keyframes_index(s);
+        while (avio_tell(ioc) < max_pos - 2 &&
+               amf_get_string(ioc, str_val, sizeof(str_val), rot) > 0)
+            if (amf_parse_object(s, astream, vstream, str_val, max_pos,
+                                 depth + 1) < 0)
+                return -1;     // if we couldn't skip, bomb out.
+        if (xvio_r8(ioc, rot) != AMF_END_OF_OBJECT) {
+            av_log(s, AV_LOG_ERROR, "Missing AMF_END_OF_OBJECT in AMF_DATA_TYPE_OBJECT\n");
+            return -1;
+        }
+        break;
+    case AMF_DATA_TYPE_NULL:
+    case AMF_DATA_TYPE_UNDEFINED:
+    case AMF_DATA_TYPE_UNSUPPORTED:
+        break;     // these take up no additional space
+    case AMF_DATA_TYPE_MIXEDARRAY:
+    {
+        unsigned v;
+        avio_skip(ioc, 4);     // skip 32-bit max array index
+        while (avio_tell(ioc) < max_pos - 2 &&
+               amf_get_string(ioc, str_val, sizeof(str_val), rot) > 0)
+            // this is the only case in which we would want a nested
+            // parse to not skip over the object
+            if (amf_parse_object(s, astream, vstream, str_val, max_pos,
+                                 depth + 1) < 0)
+                return -1;
+        v = xvio_r8(ioc, rot);
+        if (v != AMF_END_OF_OBJECT) {
+            av_log(s, AV_LOG_ERROR, "Missing AMF_END_OF_OBJECT in AMF_DATA_TYPE_MIXEDARRAY, found %d\n", v);
+            return -1;
+        }
+        break;
+    }
+    case AMF_DATA_TYPE_ARRAY:
+    {
+        unsigned int arraylen, i;
+
+        arraylen = xvio_rb32(ioc, rot);
+        for (i = 0; i < arraylen && avio_tell(ioc) < max_pos - 1; i++)
+            if (amf_parse_object(s, NULL, NULL, NULL, max_pos,
+                                 depth + 1) < 0)
+                return -1;      // if we couldn't skip, bomb out.
+    }
+    break;
+    case AMF_DATA_TYPE_DATE:
+        avio_skip(ioc, 8 + 2);  // timestamp (double) and UTC offset (int16)
+        break;
+    default:                    // unsupported type, we couldn't skip
+        av_log(s, AV_LOG_ERROR, "unsupported amf type %d\n", amf_type);
+        return -1;
+    }
+
+    if (key) {
+        apar = astream ? astream->codecpar : NULL;
+        vpar = vstream ? vstream->codecpar : NULL;
+
+        // stream info doesn't live any deeper than the first object
+        if (depth == 1) {
+            if (amf_type == AMF_DATA_TYPE_NUMBER ||
+                amf_type == AMF_DATA_TYPE_BOOL) {
+                if (!strcmp(key, "duration"))
+                    s->duration = num_val * AV_TIME_BASE;
+                else if (!strcmp(key, "videodatarate") &&
+                         0 <= (int)(num_val * 1024.0))
+                    xv->video_bit_rate = num_val * 1024.0;
+                else if (!strcmp(key, "audiodatarate") &&
+                         0 <= (int)(num_val * 1024.0))
+                    xv->audio_bit_rate = num_val * 1024.0;
+                else if (!strcmp(key, "datastream")) {
+                    AVStream *st = create_stream(s, AVMEDIA_TYPE_SUBTITLE);
+                    if (!st)
+                        return AVERROR(ENOMEM);
+                    st->codecpar->codec_id = AV_CODEC_ID_TEXT;
+                } else if (!strcmp(key, "framerate")) {
+                    xv->framerate = av_d2q(num_val, 1000);
+                    if (vstream)
+                        vstream->avg_frame_rate = xv->framerate;
+                } else if (xv->trust_metadata) {
+                    if (!strcmp(key, "videocodecid") && vpar) {
+                        int ret = xv_set_video_codec(s, vstream, num_val, 0);
+                        if (ret < 0)
+                            return ret;
+                    } else if (!strcmp(key, "audiocodecid") && apar) {
+                        int id = ((int)num_val) << FLV_AUDIO_CODECID_OFFSET;
+                        xv_set_audio_codec(s, astream, apar, id);
+                    } else if (!strcmp(key, "audiosamplerate") && apar) {
+                        apar->sample_rate = num_val;
+                    } else if (!strcmp(key, "audiosamplesize") && apar) {
+                        apar->bits_per_coded_sample = num_val;
+                    } else if (!strcmp(key, "stereo") && apar) {
+                        apar->channels       = num_val + 1;
+                        apar->channel_layout = apar->channels == 2 ?
+                                               AV_CH_LAYOUT_STEREO :
+                                               AV_CH_LAYOUT_MONO;
+                    } else if (!strcmp(key, "width") && vpar) {
+                        vpar->width = num_val;
+                    } else if (!strcmp(key, "height") && vpar) {
+                        vpar->height = num_val;
+                    }
+                }
+            }
+            if (amf_type == AMF_DATA_TYPE_STRING) {
+                if (!strcmp(key, "encoder")) {
+                    int version = -1;
+                    if (1 == sscanf(str_val, "Open Broadcaster Software v0.%d", &version)) {
+                        if (version > 0 && version <= 655)
+                            xv->broken_sizes = 1;
+                    }
+                } else if (!strcmp(key, "metadatacreator")) {
+                    if (   !strcmp (str_val, "MEGA")
+                        || !strncmp(str_val, "FlixEngine", 10))
+                        xv->broken_sizes = 1;
+                }
+            }
+        }
+
+        if (amf_type == AMF_DATA_TYPE_OBJECT && s->nb_streams == 1 &&
+           ((!apar && !strcmp(key, "audiocodecid")) ||
+            (!vpar && !strcmp(key, "videocodecid"))))
+                s->ctx_flags &= ~AVFMTCTX_NOHEADER; //If there is either audio/video missing, codecid will be an empty object
+
+        if ((!strcmp(key, "duration")        ||
+            !strcmp(key, "filesize")        ||
+            !strcmp(key, "width")           ||
+            !strcmp(key, "height")          ||
+            !strcmp(key, "videodatarate")   ||
+            !strcmp(key, "framerate")       ||
+            !strcmp(key, "videocodecid")    ||
+            !strcmp(key, "audiodatarate")   ||
+            !strcmp(key, "audiosamplerate") ||
+            !strcmp(key, "audiosamplesize") ||
+            !strcmp(key, "stereo")          ||
+            !strcmp(key, "audiocodecid")    ||
+            !strcmp(key, "datastream")) && !xv->dump_full_metadata)
+            return 0;
+
+        s->event_flags |= AVFMT_EVENT_FLAG_METADATA_UPDATED;
+        if (amf_type == AMF_DATA_TYPE_BOOL) {
+            av_strlcpy(str_val, num_val > 0 ? "true" : "false",
+                       sizeof(str_val));
+            av_dict_set(&s->metadata, key, str_val, 0);
+        } else if (amf_type == AMF_DATA_TYPE_NUMBER) {
+            snprintf(str_val, sizeof(str_val), "%.f", num_val);
+            av_dict_set(&s->metadata, key, str_val, 0);
+        } else if (amf_type == AMF_DATA_TYPE_STRING)
+            av_dict_set(&s->metadata, key, str_val, 0);
+    }
+
+    return 0;
+}
+
+#define TYPE_ONTEXTDATA 1
+#define TYPE_ONCAPTION 2
+#define TYPE_ONCAPTIONINFO 3
+#define TYPE_UNKNOWN 9
+
+static int xv_read_metabody(AVFormatContext *s, int64_t next_pos)
+{
+    XVContext *xv = s->priv_data;
+    AMFDataType type;
+    AVStream *stream, *astream, *vstream;
+    AVStream av_unused *dstream;
+    AVIOContext *ioc;
+    int i;
+    char buffer[32];
+    int rot;
+    if(xv->rot_value){
+        rot = xv->rot_value;
+    }
+    else{
+        rot = find_rot(s->pb);
+        xv->rot_value = rot;
+    }
+
+    astream = NULL;
+    vstream = NULL;
+    dstream = NULL;
+    ioc     = s->pb;
+
+    // first object needs to be "onMetaData" string
+    type = xvio_r8(ioc, rot);
+    if (type != AMF_DATA_TYPE_STRING ||
+        amf_get_string(ioc, buffer, sizeof(buffer), rot) < 0)
+        return TYPE_UNKNOWN;
+
+    if (!strcmp(buffer, "onTextData"))
+        return TYPE_ONTEXTDATA;
+
+    if (!strcmp(buffer, "onCaption"))
+        return TYPE_ONCAPTION;
+
+    if (!strcmp(buffer, "onCaptionInfo"))
+        return TYPE_ONCAPTIONINFO;
+
+    if (strcmp(buffer, "onMetaData") && strcmp(buffer, "onCuePoint")) {
+        av_log(s, AV_LOG_DEBUG, "Unknown type %s\n", buffer);
+        return TYPE_UNKNOWN;
+    }
+
+    // find the streams now so that amf_parse_object doesn't need to do
+    // the lookup every time it is called.
+    for (i = 0; i < s->nb_streams; i++) {
+        stream = s->streams[i];
+        if (stream->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
+            vstream = stream;
+            xv->last_keyframe_stream_index = i;
+        } else if (stream->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
+            astream = stream;
+            if (xv->last_keyframe_stream_index == -1)
+                xv->last_keyframe_stream_index = i;
+        }
+        else if (stream->codecpar->codec_type == AVMEDIA_TYPE_SUBTITLE)
+            dstream = stream;
+    }
+
+    // parse the second object (we want a mixed array)
+    if (amf_parse_object(s, astream, vstream, buffer, next_pos, 0) < 0)
+        return -1;
+
+    return 0;
+}
+
+
+
+static int xv_read_header(AVFormatContext *s)
+{
+    int flags;
+    XVContext *xv = s->priv_data;
+    int offset;
+    int pre_tag_size = 0;
+    int rot;
+    if(!xv->rot_value){
+        rot = find_rot(s->pb);
+        xv->rot_value = rot;
+    }
+    else{
+        rot = xv->rot_value;
+    }
+    avio_seek(s->pb, 0x200004, SEEK_SET);
+    flags = xvio_r8(s->pb, rot);
+
+    xv->missing_streams = flags & (FLV_HEADER_FLAG_HASVIDEO | FLV_HEADER_FLAG_HASAUDIO);
+
+    s->ctx_flags |= AVFMTCTX_NOHEADER;
+
+    offset = xvio_rb32(s->pb, rot) + 0x200000;
+
+    avio_seek(s->pb, offset, SEEK_SET);
+
+    /* Annex E. The FLV File Format
+     * E.3 TheFLVFileBody
+     *     Field               Type    Comment
+     *     PreviousTagSize0    UI32    Always 0
+     * */
+    pre_tag_size = xvio_rb32(s->pb, rot);
+    if (pre_tag_size) {
+        av_log(s, AV_LOG_WARNING, "Read FLV header error, input file is not a standard xv format, first PreviousTagSize0 always is 0\n");
+    }
+
+    s->start_time = 0;
+    xv->sum_flv_tag_size = 0;
+    xv->last_keyframe_stream_index = -1;
+
+    return 0;
+}
+
+static int xv_read_close(AVFormatContext *s)
+{
+    int i;
+    XVContext *xv = s->priv_data;
+    for (i=0; i<FLV_STREAM_TYPE_NB; i++)
+        av_freep(&xv->new_extradata[i]);
+    av_freep(&xv->keyframe_times);
+    av_freep(&xv->keyframe_filepositions);
+    return 0;
+}
+
+static int xv_get_extradata(AVFormatContext *s, AVStream *st, int size)
+{
+    if (!size)
+        return 0;
+
+    av_freep(&st->codecpar->extradata);
+    if (ff_get_extradata(s, st->codecpar, s->pb, size) < 0)
+        return AVERROR(ENOMEM);
+    st->internal->need_context_update = 1;
+    return 0;
+}
+
+static int xv_queue_extradata(XVContext *xv, AVIOContext *pb, int stream,
+                               int size)
+{
+    if (!size)
+        return 0;
+
+    av_free(xv->new_extradata[stream]);
+    xv->new_extradata[stream] = av_mallocz(size +
+                                            AV_INPUT_BUFFER_PADDING_SIZE);
+    if (!xv->new_extradata[stream])
+        return AVERROR(ENOMEM);
+    xv->new_extradata_size[stream] = size;
+    avio_read(pb, xv->new_extradata[stream], size);
+    return 0;
+}
+
+static void clear_index_entries(AVFormatContext *s, int64_t pos)
+{
+    int i, j, out;
+    av_log(s, AV_LOG_WARNING,
+           "Found invalid index entries, clearing the index.\n");
+    for (i = 0; i < s->nb_streams; i++) {
+        AVStream *st = s->streams[i];
+        /* Remove all index entries that point to >= pos */
+        out = 0;
+        for (j = 0; j < st->nb_index_entries; j++)
+            if (st->index_entries[j].pos < pos)
+                st->index_entries[out++] = st->index_entries[j];
+        st->nb_index_entries = out;
+    }
+}
+
+static int amf_skip_tag(AVIOContext *pb, AMFDataType type)
+{
+    int nb = -1, ret, parse_name = 1;
+
+    switch (type) {
+    case AMF_DATA_TYPE_NUMBER:
+        avio_skip(pb, 8);
+        break;
+    case AMF_DATA_TYPE_BOOL:
+        avio_skip(pb, 1);
+        break;
+    case AMF_DATA_TYPE_STRING:
+        avio_skip(pb, avio_rb16(pb));
+        break;
+    case AMF_DATA_TYPE_ARRAY:
+        parse_name = 0;
+    case AMF_DATA_TYPE_MIXEDARRAY:
+        nb = avio_rb32(pb);
+    case AMF_DATA_TYPE_OBJECT:
+        while(!pb->eof_reached && (nb-- > 0 || type != AMF_DATA_TYPE_ARRAY)) {
+            if (parse_name) {
+                int size = avio_rb16(pb);
+                if (!size) {
+                    avio_skip(pb, 1);
+                    break;
+                }
+                avio_skip(pb, size);
+            }
+            if ((ret = amf_skip_tag(pb, avio_r8(pb))) < 0)
+                return ret;
+        }
+        break;
+    case AMF_DATA_TYPE_NULL:
+    case AMF_DATA_TYPE_OBJECT_END:
+        break;
+    default:
+        return AVERROR_INVALIDDATA;
+    }
+    return 0;
+}
+
+static int xv_data_packet(AVFormatContext *s, AVPacket *pkt,
+                           int64_t dts, int64_t next)
+{
+    AVIOContext *pb = s->pb;
+    XVContext *xv = s->priv_data;
+    AVStream *st    = NULL;
+    char buf[20];
+    int ret = AVERROR_INVALIDDATA;
+    int i, length = -1;
+    int array = 0;
+    int rot;
+    if(xv->rot_value){
+        rot = xv->rot_value;
+    }
+    else{
+        rot = find_rot(s->pb);
+        xv->rot_value = rot;
+    }
+
+    switch (xvio_r8(pb,rot)) {
+    case AMF_DATA_TYPE_ARRAY:
+        array = 1;
+    case AMF_DATA_TYPE_MIXEDARRAY:
+        avio_seek(pb, 4, SEEK_CUR);
+    case AMF_DATA_TYPE_OBJECT:
+        break;
+    default:
+        goto skip;
+    }
+
+    while (array || (ret = amf_get_string(pb, buf, sizeof(buf), rot)) > 0) {
+        AMFDataType type = xvio_r8(pb,rot);
+        if (type == AMF_DATA_TYPE_STRING && (array || !strcmp(buf, "text"))) {
+            length = xvio_rb16(pb, rot);
+            ret    = av_get_packet(pb, pkt, length);
+            if (ret < 0)
+                goto skip;
+            else
+                break;
+        } else {
+            if ((ret = amf_skip_tag(pb, type)) < 0)
+                goto skip;
+        }
+    }
+
+    if (length < 0) {
+        ret = AVERROR_INVALIDDATA;
+        goto skip;
+    }
+
+    for (i = 0; i < s->nb_streams; i++) {
+        st = s->streams[i];
+        if (st->codecpar->codec_type == AVMEDIA_TYPE_SUBTITLE)
+            break;
+    }
+
+    if (i == s->nb_streams) {
+        st = create_stream(s, AVMEDIA_TYPE_SUBTITLE);
+        if (!st)
+            return AVERROR(ENOMEM);
+        st->codecpar->codec_id = AV_CODEC_ID_TEXT;
+    }
+
+    pkt->dts  = dts;
+    pkt->pts  = dts;
+    pkt->size = ret;
+
+    pkt->stream_index = st->index;
+    pkt->flags       |= AV_PKT_FLAG_KEY;
+
+skip:
+    avio_seek(s->pb, next + 4, SEEK_SET);
+
+    return ret;
+}
+
+static int resync(AVFormatContext *s)
+{
+    XVContext *xv = s->priv_data;
+    int64_t i;
+    int64_t pos = avio_tell(s->pb);
+    int rot;
+    if(xv->rot_value){
+        rot = xv->rot_value;
+    }
+    else{
+        rot = find_rot(s->pb);
+        xv->rot_value = rot;
+    }
+
+    for (i=0; !avio_feof(s->pb); i++) {
+        int j  = i & (RESYNC_BUFFER_SIZE-1);
+        int j1 = j + RESYNC_BUFFER_SIZE;
+        xv->resync_buffer[j ] =
+        xv->resync_buffer[j1] = xvio_r8(s->pb,rot);
+
+        if (i >= 8 && pos) {
+            uint8_t *d = xv->resync_buffer + j1 - 8;
+            if (d[0] == 'F' &&
+                d[1] == 'L' &&
+                d[2] == 'V' &&
+                d[3] < 5 && d[5] == 0) {
+                av_log(s, AV_LOG_WARNING, "Concatenated FLV detected, might fail to demux, decode and seek %"PRId64"\n", xv->last_ts);
+                xv->time_offset = xv->last_ts + 1;
+                xv->time_pos    = avio_tell(s->pb);
+            }
+        }
+
+        if (i > 22) {
+            unsigned lsize2 = AV_RB32(xv->resync_buffer + j1 - 4);
+            if (lsize2 >= 11 && lsize2 + 8LL < FFMIN(i, RESYNC_BUFFER_SIZE)) {
+                unsigned  size2 = AV_RB24(xv->resync_buffer + j1 - lsize2 + 1 - 4);
+                unsigned lsize1 = AV_RB32(xv->resync_buffer + j1 - lsize2 - 8);
+                if (lsize1 >= 11 && lsize1 + 8LL + lsize2 < FFMIN(i, RESYNC_BUFFER_SIZE)) {
+                    unsigned  size1 = AV_RB24(xv->resync_buffer + j1 - lsize1 + 1 - lsize2 - 8);
+                    if (size1 == lsize1 - 11 && size2  == lsize2 - 11) {
+                        avio_seek(s->pb, pos + i - lsize1 - lsize2 - 8, SEEK_SET);
+                        return 1;
+                    }
+                }
+            }
+        }
+    }
+    return AVERROR_EOF;
+}
+
+static int xv_read_packet(AVFormatContext *s, AVPacket *pkt)
+{
+    XVContext *xv = s->priv_data;
+    int ret, i, size, flags;
+    enum FlvTagType type;
+    int stream_type=-1;
+    int64_t next, pos, meta_pos;
+    int64_t dts, pts = AV_NOPTS_VALUE;
+    int av_uninit(channels);
+    int av_uninit(sample_rate);
+    AVStream *st    = NULL;
+    int last = -1;
+    int orig_size;
+    int rot;
+    if(xv->rot_value){
+        rot=xv->rot_value;
+    }
+    else{
+        rot = find_rot(s->pb);
+        xv->rot_value = rot;
+    }
+
+retry:
+    /* pkt size is repeated at end. skip it */
+        pos  = avio_tell(s->pb);
+        type = (xvio_r8(s->pb, rot) & 0x1F);
+        orig_size =
+        size = xvio_rb24(s->pb, rot);
+        xv->sum_flv_tag_size += size + 11;
+        dts  = xvio_rb24(s->pb, rot);
+        dts |= (unsigned)xvio_r8(s->pb, rot) << 24;
+        av_log(s, AV_LOG_TRACE, "type:%d, size:%d, last:%d, dts:%"PRId64" pos:%"PRId64"\n", type, size, last, dts, avio_tell(s->pb));
+        if (avio_feof(s->pb))
+            return AVERROR_EOF;
+        avio_skip(s->pb, 3); /* stream id, always 0 */
+        flags = 0;
+
+        if (xv->validate_next < xv->validate_count) {
+            int64_t validate_pos = xv->validate_index[xv->validate_next].pos;
+            if (pos == validate_pos) {
+                if (FFABS(dts - xv->validate_index[xv->validate_next].dts) <=
+                    VALIDATE_INDEX_TS_THRESH) {
+                    xv->validate_next++;
+                } else {
+                    clear_index_entries(s, validate_pos);
+                    xv->validate_count = 0;
+                }
+            } else if (pos > validate_pos) {
+                clear_index_entries(s, validate_pos);
+                xv->validate_count = 0;
+            }
+        }
+
+        if (size == 0) {
+            ret = FFERROR_REDO;
+            goto leave;
+        }
+
+        next = size + avio_tell(s->pb);
+
+        if (type == FLV_TAG_TYPE_AUDIO) {
+            stream_type = FLV_STREAM_TYPE_AUDIO;
+            flags    = xvio_r8(s->pb, rot);
+            size--;
+        } else if (type == FLV_TAG_TYPE_VIDEO) {
+            stream_type = FLV_STREAM_TYPE_VIDEO;
+            flags    = xvio_r8(s->pb, rot);
+            size--;
+            if ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_VIDEO_INFO_CMD)
+                goto skip;
+        } else if (type == FLV_TAG_TYPE_META) {
+            stream_type=FLV_STREAM_TYPE_SUBTITLE;
+            if (size > 13 + 1 + 4) { // Header-type metadata stuff
+                int type;
+                meta_pos = avio_tell(s->pb);
+                type = xv_read_metabody(s, next);
+                if (type == 0 && dts == 0 || type < 0) {
+                    if (type < 0 && xv->validate_count &&
+                        xv->validate_index[0].pos     > next &&
+                        xv->validate_index[0].pos - 4 < next
+                    ) {
+                        av_log(s, AV_LOG_WARNING, "Adjusting next position due to index mismatch\n");
+                        next = xv->validate_index[0].pos - 4;
+                    }
+                    goto skip;
+                } else if (type == TYPE_ONTEXTDATA) {
+                    avpriv_request_sample(s, "OnTextData packet");
+                    return xv_data_packet(s, pkt, dts, next);
+                } else if (type == TYPE_ONCAPTION) {
+                    return xv_data_packet(s, pkt, dts, next);
+                } else if (type == TYPE_UNKNOWN) {
+                    stream_type = FLV_STREAM_TYPE_DATA;
+                }
+                avio_seek(s->pb, meta_pos, SEEK_SET);
+            }
+        } else {
+            av_log(s, AV_LOG_DEBUG,
+                   "Skipping xv packet: type %d, size %d, flags %d.\n",
+                   type, size, flags);
+skip:
+            if (avio_seek(s->pb, next, SEEK_SET) != next) {
+                 // This can happen if xv_read_metabody above read past
+                 // next, on a non-seekable input, and the preceding data has
+                 // been flushed out from the IO buffer.
+                 av_log(s, AV_LOG_ERROR, "Unable to seek to the next packet\n");
+                 return AVERROR_INVALIDDATA;
+            }
+            ret = FFERROR_REDO;
+            goto leave;
+        }
+
+        /* skip empty data packets */
+        if (!size) {
+            ret = FFERROR_REDO;
+            goto leave;
+        }
+
+        /* now find stream */
+        for (i = 0; i < s->nb_streams; i++) {
+            st = s->streams[i];
+            if (stream_type == FLV_STREAM_TYPE_AUDIO) {
+                if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO &&
+                    (s->audio_codec_id || flv_same_audio_codec(st->codecpar, flags)))
+                    break;
+            } else if (stream_type == FLV_STREAM_TYPE_VIDEO) {
+                if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO &&
+                    (s->video_codec_id || flv_same_video_codec(st->codecpar, flags)))
+                    break;
+            } else if (stream_type == FLV_STREAM_TYPE_SUBTITLE) {
+                if (st->codecpar->codec_type == AVMEDIA_TYPE_SUBTITLE)
+                    break;
+            } else if (stream_type == FLV_STREAM_TYPE_DATA) {
+                if (st->codecpar->codec_type == AVMEDIA_TYPE_DATA)
+                    break;
+            }
+        }
+        if (i == s->nb_streams) {
+            static const enum AVMediaType stream_types[] = {AVMEDIA_TYPE_VIDEO, AVMEDIA_TYPE_AUDIO, AVMEDIA_TYPE_SUBTITLE, AVMEDIA_TYPE_DATA};
+            st = create_stream(s, stream_types[stream_type]);
+            if (!st)
+                return AVERROR(ENOMEM);
+
+        }
+        av_log(s, AV_LOG_TRACE, "%d %X %d \n", stream_type, flags, st->discard);
+
+        if (xv->time_pos <= pos) {
+            dts += xv->time_offset;
+        }
+
+        if ((s->pb->seekable & AVIO_SEEKABLE_NORMAL) &&
+            ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY ||
+              stream_type == FLV_STREAM_TYPE_AUDIO))
+            av_add_index_entry(st, pos, dts, size, 0, AVINDEX_KEYFRAME);
+
+        if (  (st->discard >= AVDISCARD_NONKEY && !((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY || (stream_type == FLV_STREAM_TYPE_AUDIO)))
+            ||(st->discard >= AVDISCARD_BIDIR  &&  ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_DISP_INTER && (stream_type == FLV_STREAM_TYPE_VIDEO)))
+            || st->discard >= AVDISCARD_ALL
+        ) {
+            avio_seek(s->pb, next, SEEK_SET);
+            ret = FFERROR_REDO;
+            goto leave;
+        }
+
+    // if not streamed and no duration from metadata then seek to end to find
+    // the duration from the timestamps
+    if ((s->pb->seekable & AVIO_SEEKABLE_NORMAL) &&
+        (!s->duration || s->duration == AV_NOPTS_VALUE) &&
+        !xv->searched_for_end) {
+        int size;
+        const int64_t pos   = avio_tell(s->pb);
+        // Read the last 4 bytes of the file, this should be the size of the
+        // previous FLV tag. Use the timestamp of its payload as duration.
+        int64_t fsize       = avio_size(s->pb);
+retry_duration:
+        avio_seek(s->pb, fsize - 4, SEEK_SET);
+        size = xvio_rb32(s->pb, rot);
+        if (size > 0 && size < fsize) {
+            // Seek to the start of the last FLV tag at position (fsize - 4 - size)
+            // but skip the byte indicating the type.
+            avio_seek(s->pb, fsize - 3 - size, SEEK_SET);
+            if (size == xvio_rb24(s->pb, rot) + 11) {
+                uint32_t ts = xvio_rb24(s->pb, rot);
+                ts         |= xvio_r8(s->pb, rot) << 24;
+                if (ts)
+                    s->duration = ts * (int64_t)AV_TIME_BASE / 1000;
+                else if (fsize >= 8 && fsize - 8 >= size) {
+                    fsize -= size+4;
+                    goto retry_duration;
+                }
+            }
+        }
+
+        avio_seek(s->pb, pos, SEEK_SET);
+        xv->searched_for_end = 1;
+    }
+
+    if (stream_type == FLV_STREAM_TYPE_AUDIO) {
+        int bits_per_coded_sample;
+        channels = (flags & FLV_AUDIO_CHANNEL_MASK) == FLV_STEREO ? 2 : 1;
+        sample_rate = 44100 << ((flags & FLV_AUDIO_SAMPLERATE_MASK) >>
+                                FLV_AUDIO_SAMPLERATE_OFFSET) >> 3;
+        bits_per_coded_sample = (flags & FLV_AUDIO_SAMPLESIZE_MASK) ? 16 : 8;
+        if (!st->codecpar->channels || !st->codecpar->sample_rate ||
+            !st->codecpar->bits_per_coded_sample) {
+            st->codecpar->channels              = channels;
+            st->codecpar->channel_layout        = channels == 1
+                                               ? AV_CH_LAYOUT_MONO
+                                               : AV_CH_LAYOUT_STEREO;
+            st->codecpar->sample_rate           = sample_rate;
+            st->codecpar->bits_per_coded_sample = bits_per_coded_sample;
+        }
+        if (!st->codecpar->codec_id) {
+            xv_set_audio_codec(s, st, st->codecpar,
+                                flags & FLV_AUDIO_CODECID_MASK);
+            xv->last_sample_rate =
+            sample_rate           = st->codecpar->sample_rate;
+            xv->last_channels    =
+            channels              = st->codecpar->channels;
+        } else {
+            AVCodecParameters *par = avcodec_parameters_alloc();
+            if (!par) {
+                ret = AVERROR(ENOMEM);
+                goto leave;
+            }
+            par->sample_rate = sample_rate;
+            par->bits_per_coded_sample = bits_per_coded_sample;
+            xv_set_audio_codec(s, st, par, flags & FLV_AUDIO_CODECID_MASK);
+            sample_rate = par->sample_rate;
+            avcodec_parameters_free(&par);
+        }
+    } else if (stream_type == FLV_STREAM_TYPE_VIDEO) {
+        int ret = xv_set_video_codec(s, st, flags & FLV_VIDEO_CODECID_MASK, 1);
+        if (ret < 0)
+            return ret;
+        size -= ret;
+    } else if (stream_type == FLV_STREAM_TYPE_SUBTITLE) {
+        st->codecpar->codec_id = AV_CODEC_ID_TEXT;
+    } else if (stream_type == FLV_STREAM_TYPE_DATA) {
+        st->codecpar->codec_id = AV_CODEC_ID_NONE; // Opaque AMF data
+    }
+
+    if (st->codecpar->codec_id == AV_CODEC_ID_AAC ||
+        st->codecpar->codec_id == AV_CODEC_ID_H264 ||
+        st->codecpar->codec_id == AV_CODEC_ID_MPEG4) {
+        int type = xvio_r8(s->pb, rot);
+        size--;
+
+        if (size < 0) {
+            ret = AVERROR_INVALIDDATA;
+            goto leave;
+        }
+
+        if (st->codecpar->codec_id == AV_CODEC_ID_H264 || st->codecpar->codec_id == AV_CODEC_ID_MPEG4) {
+            // sign extension
+            int32_t cts = (xvio_rb24(s->pb, rot) + 0xff800000) ^ 0xff800000;
+            pts = dts + cts;
+            if (cts < 0) { // dts might be wrong
+                if (!xv->wrong_dts)
+                    av_log(s, AV_LOG_WARNING,
+                        "Negative cts, previous timestamps might be wrong.\n");
+                xv->wrong_dts = 1;
+            } else if (FFABS(dts - pts) > 1000*60*15) {
+                av_log(s, AV_LOG_WARNING,
+                       "invalid timestamps %"PRId64" %"PRId64"\n", dts, pts);
+                dts = pts = AV_NOPTS_VALUE;
+            }
+        }
+        if (type == 0 && (!st->codecpar->extradata || st->codecpar->codec_id == AV_CODEC_ID_AAC ||
+            st->codecpar->codec_id == AV_CODEC_ID_H264)) {
+            AVDictionaryEntry *t;
+
+            if (st->codecpar->extradata) {
+                if ((ret = xv_queue_extradata(xv, s->pb, stream_type, size)) < 0)
+                    return ret;
+                ret = FFERROR_REDO;
+                goto leave;
+            }
+            if ((ret = xv_get_extradata(s, st, size)) < 0)
+                return ret;
+
+            /* Workaround for buggy Omnia A/XE encoder */
+            t = av_dict_get(s->metadata, "Encoder", NULL, 0);
+            if (st->codecpar->codec_id == AV_CODEC_ID_AAC && t && !strcmp(t->value, "Omnia A/XE"))
+                st->codecpar->extradata_size = 2;
+
+            if (st->codecpar->codec_id == AV_CODEC_ID_AAC && 0) {
+                MPEG4AudioConfig cfg;
+
+                if (avpriv_mpeg4audio_get_config(&cfg, st->codecpar->extradata,
+                                                 st->codecpar->extradata_size * 8, 1) >= 0) {
+                st->codecpar->channels       = cfg.channels;
+                st->codecpar->channel_layout = 0;
+                if (cfg.ext_sample_rate)
+                    st->codecpar->sample_rate = cfg.ext_sample_rate;
+                else
+                    st->codecpar->sample_rate = cfg.sample_rate;
+                av_log(s, AV_LOG_TRACE, "mp4a config channels %d sample rate %d\n",
+                        st->codecpar->channels, st->codecpar->sample_rate);
+                }
+            }
+
+            ret = FFERROR_REDO;
+            goto leave;
+        }
+    }
+
+    /* skip empty data packets */
+    if (!size) {
+        ret = FFERROR_REDO;
+        goto leave;
+    }
+
+    ret = av_get_packet(s->pb, pkt, size);
+    if (ret < 0)
+        return ret;
+    pkt->dts          = dts;
+    pkt->pts          = pts == AV_NOPTS_VALUE ? dts : pts;
+    pkt->stream_index = st->index;
+    pkt->pos          = pos;
+    if (xv->new_extradata[stream_type]) {
+        uint8_t *side = av_packet_new_side_data(pkt, AV_PKT_DATA_NEW_EXTRADATA,
+                                                xv->new_extradata_size[stream_type]);
+        if (side) {
+            memcpy(side, xv->new_extradata[stream_type],
+                   xv->new_extradata_size[stream_type]);
+            av_freep(&xv->new_extradata[stream_type]);
+            xv->new_extradata_size[stream_type] = 0;
+        }
+    }
+    if (stream_type == FLV_STREAM_TYPE_AUDIO &&
+                    (sample_rate != xv->last_sample_rate ||
+                     channels    != xv->last_channels)) {
+        xv->last_sample_rate = sample_rate;
+        xv->last_channels    = channels;
+        ff_add_param_change(pkt, channels, 0, sample_rate, 0, 0);
+    }
+
+    if (    stream_type == FLV_STREAM_TYPE_AUDIO ||
+            ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY) ||
+            stream_type == FLV_STREAM_TYPE_SUBTITLE ||
+            stream_type == FLV_STREAM_TYPE_DATA)
+        pkt->flags |= AV_PKT_FLAG_KEY;
+
+leave:
+    last = xvio_rb32(s->pb, rot);
+    if (!xv->trust_datasize) {
+        if (last != orig_size + 11 && last != orig_size + 10 &&
+            !avio_feof(s->pb) &&
+            (last != orig_size || !last) && last != xv->sum_flv_tag_size &&
+            !xv->broken_sizes) {
+            av_log(s, AV_LOG_ERROR, "Packet mismatch %d %d %d\n", last, orig_size + 11, xv->sum_flv_tag_size);
+            avio_seek(s->pb, pos + 1, SEEK_SET);
+            ret = resync(s);
+            av_packet_unref(pkt);
+            if (ret >= 0) {
+                goto retry;
+            }
+        }
+    }
+
+    if (ret >= 0)
+        xv->last_ts = pkt->dts;
+
+    return ret;
+}
+
+static int xv_read_seek(AVFormatContext *s, int stream_index,
+                         int64_t ts, int flags)
+{
+    XVContext *xv = s->priv_data;
+    xv->validate_count = 0;
+    return avio_seek_time(s->pb, stream_index, ts, flags);
+}
+
+#define OFFSET(x) offsetof(XVContext, x)
+#define VD AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_DECODING_PARAM
+static const AVOption options[] = {
+    { "flv_metadata", "Allocate streams according to the onMetaData array", OFFSET(trust_metadata), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, VD },
+    { "flv_full_metadata", "Dump full metadata of the onMetadata", OFFSET(dump_full_metadata), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, VD },
+    { "flv_ignore_prevtag", "Ignore the Size of previous tag", OFFSET(trust_datasize), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, VD },
+    { "missing_streams", "", OFFSET(missing_streams), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 0xFF, VD | AV_OPT_FLAG_EXPORT | AV_OPT_FLAG_READONLY },
+    { NULL }
+};
+
+static const AVClass xv_class = {
+    .class_name = "xvdec",
+    .item_name  = av_default_item_name,
+    .option     = options,
+    .version    = LIBAVUTIL_VERSION_INT,
+};
+
+AVInputFormat ff_xv_demuxer = {
+    .name           = "xv",
+    .long_name      = NULL_IF_CONFIG_SMALL("Xunlei Video File"),
+    .priv_data_size = sizeof(XVContext),
+    .read_probe     = xv_probe,
+    .read_header    = xv_read_header,
+    .read_packet    = xv_read_packet,
+    .read_seek      = xv_read_seek,
+    .read_close     = xv_read_close,
+    .extensions     = "xv",
+    .priv_class     = &xv_class,
+};
+
diff --git a/libavformat/xvtools.h b/libavformat/xvtools.h
new file mode 100644
index 0000000000..42c2c65c46
--- /dev/null
+++ b/libavformat/xvtools.h
@@ -0,0 +1,95 @@
+int flvid = 0x46;
+
+
+int byte_shift(int byte,int shift);
+int find_rot(AVIOContext *pb);
+int xvio_r8(AVIOContext *pb, int rot);
+unsigned int xvio_rb16(AVIOContext *s, int rot);
+unsigned int xvio_rb24(AVIOContext *s, int rot);
+unsigned int xvio_rb32(AVIOContext *s, int rot);
+uint64_t xvio_rb64(AVIOContext *s, int rot);
+int xv_string_decrypt(int64_t curr_pos, char *buffer, int length, int rot);
+
+
+
+int byte_shift(int byte,int shift){
+    return ((byte + shift)&0xff);
+}
+
+
+int find_rot(AVIOContext *pb){
+    int64_t curr_pos = avio_tell(pb);
+    avio_seek(pb,0x200000,SEEK_SET);
+    int rot = flvid - avio_r8(pb);
+    avio_seek(pb,curr_pos, SEEK_SET);
+    return rot;
+}
+
+
+
+int xvio_r8(AVIOContext *pb, int rot){
+    int64_t curr_pos = avio_tell(pb);
+    if(curr_pos < 0x200400){
+        int ret=avio_r8(pb);
+        if(ret == 0)return 0;
+        ret = byte_shift(ret,rot);
+        return ret;
+    }
+    int ret=avio_r8(pb);
+    return ret;
+}
+
+
+unsigned int xvio_rb16(AVIOContext *s, int rot)
+{
+    unsigned int val;
+    val = xvio_r8(s, rot) << 8;
+    val |= xvio_r8(s, rot);
+    return val;
+}
+
+
+unsigned int xvio_rb24(AVIOContext *s, int rot)
+{
+    unsigned int val;
+    val = xvio_rb16(s, rot) << 8;
+    val |= xvio_r8(s, rot);
+    return val;
+}
+
+
+unsigned int xvio_rb32(AVIOContext *s, int rot)
+{
+    unsigned int val;
+    val = xvio_rb16(s, rot) << 16;
+    val |= xvio_rb16(s, rot);
+    return val;
+}
+
+
+uint64_t xvio_rb64(AVIOContext *s, int rot)
+{
+    uint64_t val;
+    val = (uint64_t)xvio_rb32(s, rot) << 32;
+    val |= (uint64_t)xvio_rb32(s, rot);
+    return val;
+}
+
+
+
+int xv_string_decrypt(int64_t curr_pos, char *buffer, int length, int rot){
+    if(curr_pos>=0x200400){
+        return 0;
+    }
+    for(int i=0;i<length;i++){
+        if((curr_pos+i) < 0x200400){
+            buffer[i] = byte_shift(buffer[i],rot);
+        }
+        else{
+            break;
+        }
+    }
+    return 0;
+}
+
+
-- 
2.21.0

