[FFmpeg-devel] DVB EPG decoder

From 1cfd16650bb91ce25c03a289cf6723b02587a892 Mon Sep 17 00:00:00 2001
From: Anthony Delannoy <anthony.2lannoy@gmail.com>
Date: Wed, 21 Aug 2019 16:07:59 +0200
Subject: [PATCH 10/10] lavc/epgdec: add EPG data decoder

New EPG table decoder which store an EPGTable in AVFrame::side_data as
a AV_FRAME_DATA_EPG_TABLE type for each AVPacket decoded.
---
 Changelog              |   1 +
 configure              |   1 +
 libavcodec/Makefile    |   1 +
 libavcodec/allcodecs.c |   1 +
 libavcodec/epgdec.c    | 278 +++++++++++++++++++++++++++++++++++++++++
 5 files changed, 282 insertions(+)
 create mode 100644 libavcodec/epgdec.c

diff --git a/Changelog b/Changelog
index 52096eed0e..7a369330fe 100644
--- a/Changelog
+++ b/Changelog
@@ -2,6 +2,7 @@  Entries are sorted chronologically from oldest to youngest within each release,
 releases are sorted from youngest to oldest.
 
 version <next>:
+- EPG data decoder
 - v360 filter
 - Intel QSV-accelerated MJPEG decoding
 - Intel QSV-accelerated VP9 decoding
diff --git a/configure b/configure
index 13d9726606..4dad16d73c 100755
--- a/configure
+++ b/configure
@@ -2687,6 +2687,7 @@  eac3_encoder_select="ac3_encoder"
 eamad_decoder_select="aandcttables blockdsp bswapdsp idctdsp mpegvideo"
 eatgq_decoder_select="aandcttables"
 eatqi_decoder_select="aandcttables blockdsp bswapdsp idctdsp"
+epg_decoder_select="dvb"
 exr_decoder_deps="zlib"
 ffv1_decoder_select="rangecoder"
 ffv1_encoder_select="rangecoder"
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index e49188357b..b9c42bdb14 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -300,6 +300,7 @@  OBJS-$(CONFIG_EATQI_DECODER)           += eatqi.o eaidct.o mpeg12.o mpeg12data.o
 OBJS-$(CONFIG_EIGHTBPS_DECODER)        += 8bps.o
 OBJS-$(CONFIG_EIGHTSVX_EXP_DECODER)    += 8svx.o
 OBJS-$(CONFIG_EIGHTSVX_FIB_DECODER)    += 8svx.o
+OBJS-$(CONFIG_EPG_DECODER)             += epgdec.o
 OBJS-$(CONFIG_ESCAPE124_DECODER)       += escape124.o
 OBJS-$(CONFIG_ESCAPE130_DECODER)       += escape130.o
 OBJS-$(CONFIG_EVRC_DECODER)            += evrcdec.o acelp_vectors.o lsp.o
diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
index 22985325e0..b669c80bca 100644
--- a/libavcodec/allcodecs.c
+++ b/libavcodec/allcodecs.c
@@ -419,6 +419,7 @@  extern AVCodec ff_dss_sp_decoder;
 extern AVCodec ff_dst_decoder;
 extern AVCodec ff_eac3_encoder;
 extern AVCodec ff_eac3_decoder;
+extern AVCodec ff_epg_decoder;
 extern AVCodec ff_evrc_decoder;
 extern AVCodec ff_ffwavesynth_decoder;
 extern AVCodec ff_flac_encoder;
diff --git a/libavcodec/epgdec.c b/libavcodec/epgdec.c
new file mode 100644
index 0000000000..2003bb1905
--- /dev/null
+++ b/libavcodec/epgdec.c
@@ -0,0 +1,278 @@ 
+/*
+ * epg data decoder
+ * Copyright (c) 2019 Anthony Delannoy
+ *
+ * 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
+ */
+
+/**
+ * @file epg data decoder
+ */
+
+#include "avcodec.h"
+#include "internal.h"
+#include "decode.h"
+#include "libavutil/common.h"
+#include "libavutil/dvb.h"
+#include "libavutil/dvbdescriptors.h"
+#include "libavformat/mpegts.h"
+
+typedef struct EpgTidInfo {
+    int last_version;
+    int last_section_num;
+    int last_segment_section_num;
+} EpgTidInfo;
+
+typedef struct EPGContext {
+    const AVClass *class;
+    struct EpgTidInfo infos[4];
+    int last_sched_table_id;
+    int o_last_sched_table_id;
+    AVPacket *pkt;
+} EPGContext;
+
+static int epg_handle_descriptor(DvbDescriptorHeader *h, DvbDescriptor *desc,
+                                 EPGSubTable *subtable, const uint8_t **pp,
+                                 const uint8_t *p_end)
+{
+    void *data = desc->parse(desc, pp, p_end);
+    if (!data)
+        return AVERROR_INVALIDDATA;
+    memcpy(data, h, sizeof(DvbDescriptorHeader));
+
+    if (av_reallocp_array(&subtable->descriptors, (subtable->nb_descriptors + 1), sizeof(void*)) < 0) {
+        desc->free(data);
+        return AVERROR(ENOMEM);
+    }
+    subtable->descriptors[subtable->nb_descriptors++] = data;
+
+    return 0;
+}
+
+static int epg_receive_frame(AVCodecContext *avctx, AVFrame *frame)
+{
+    EPGContext *epg_ctx = avctx->priv_data;
+    EpgTidInfo *epg_info;
+    DvbSectionHeader h1, *h = &h1;
+    const uint8_t *p, *p_end;
+    int val, ret, max_last_table_id;
+    uint8_t next_version;
+    AVFrameSideData *sd;
+    AVBufferRef *buf_ref;
+    EPGTable *table;
+
+    if (!epg_ctx->pkt->data) {
+        ret = ff_decode_get_packet(avctx, epg_ctx->pkt);
+        if (ret < 0)
+            return ret;
+    }
+
+    p       = epg_ctx->pkt->data;
+    p_end   = p + epg_ctx->pkt->size - 4;
+
+    if (avpriv_dvb_parse_section_header(h, &p, p_end) < 0)
+        goto fail;
+
+    table = av_epg_table_alloc();
+    if (!table)
+        goto fail;
+    table->h = h1;
+
+    val = avpriv_dvb_get16(&p, p_end);
+    if (val < 0)
+        goto fail;
+    table->ts_id = val;
+
+    val = avpriv_dvb_get16(&p, p_end);
+    if (val < 0)
+        goto fail;
+    table->network_id = val;
+
+    val = avpriv_dvb_get8(&p, p_end);
+    if (val < 0)
+        goto fail;
+    table->segment_last_section_num = val;
+
+    val = avpriv_dvb_get8(&p, p_end);
+    if (val < 0)
+        goto fail;
+    table->last_tid = val;
+
+    // Check eit data
+    switch (h->tid) {
+        case EIT_TID:
+            epg_info = &epg_ctx->infos[0];
+            if (table->last_tid != EIT_TID || h->last_sec_num != table->segment_last_section_num)
+                goto fail;
+            break;
+        case OEIT_TID:
+            epg_info = &epg_ctx->infos[1];
+            if (table->last_tid != OEIT_TID || h->last_sec_num != table->segment_last_section_num)
+                goto fail;
+            break;
+        case EITS_START_TID ... EITS_END_TID:
+            epg_info = &epg_ctx->infos[2];
+            if (table->segment_last_section_num != h->sec_num)
+                goto fail;
+            max_last_table_id = FFMAX(table->last_tid, epg_ctx->last_sched_table_id);
+            if (table->last_tid != max_last_table_id)
+                goto fail;
+            epg_ctx->last_sched_table_id = max_last_table_id;
+            break;
+        case OEITS_START_TID ... OEITS_END_TID:
+            epg_info = &epg_ctx->infos[3];
+            if (table->segment_last_section_num != h->sec_num)
+                goto fail;
+            max_last_table_id = FFMAX(table->last_tid, epg_ctx->o_last_sched_table_id);
+            if (table->last_tid != max_last_table_id)
+                goto fail;
+            epg_ctx->o_last_sched_table_id = max_last_table_id;
+            break;
+        default:
+            goto fail;
+    }
+
+    next_version = (epg_info->last_version == 31) ? 0 : epg_info->last_version + 1;
+    if (epg_info->last_version != (-1) &&
+            (h->version == epg_info->last_version || h->version == next_version))
+        goto fail;
+
+    // Subtables
+    while (p < p_end) {
+        const uint8_t *desc_list_end;
+        EPGSubTable *subtable;
+
+        if (av_reallocp_array(&table->subtables, (table->nb_subtables + 1), sizeof(EPGSubTable*)) < 0)
+            goto fail;
+
+        table->subtables[table->nb_subtables] = av_epg_subtable_alloc();
+        if (!table->subtables[table->nb_subtables])
+            goto fail;
+        subtable = table->subtables[table->nb_subtables++];
+
+        // Get event_id
+        val = avpriv_dvb_get16(&p, p_end);
+        if (val < 0)
+            break;
+        subtable->event_id = val;
+
+        memcpy(subtable->start_time, p, 5);
+        p += 5;
+
+        memcpy(subtable->duration, p, 3);
+        p += 3;
+
+        val = avpriv_dvb_get16(&p, p_end);
+        if (val < 0)
+            break;
+        subtable->running_status = (val >> 13);
+        subtable->free_ca_mode = (val >> 12) & 0x1;
+        subtable->desc_loop_len = val & 0xfff;
+
+        desc_list_end = p + subtable->desc_loop_len;
+
+        // Descriptors
+        for (;;) {
+            DvbDescriptor *desc;
+            DvbDescriptorHeader h;
+            const uint8_t *desc_end;
+
+            if (av_dvb_parse_descriptor_header(&h, &p, p_end) < 0)
+                break;
+
+            if (!(desc = (DvbDescriptor*)av_dvb_get_descriptor(&h))) {
+                p += h.len;
+                continue;
+            }
+
+            desc_end = p + h.len;
+            if (desc_end > desc_list_end)
+                break;
+
+            if (epg_handle_descriptor(&h, desc, subtable, &p, desc_end) < 0)
+                break;
+
+            p = desc_end;
+        }
+        p = desc_list_end;
+    }
+
+    // CRC32
+    val = avpriv_dvb_get32(&p_end, (p_end + 4));
+    if (val < 0)
+        goto fail;
+    table->crc = val;
+
+    buf_ref = av_buffer_allocz(sizeof(*table) + AV_INPUT_BUFFER_PADDING_SIZE);
+    if (!buf_ref)
+        goto fail;
+    buf_ref->data = (uint8_t*)table;
+    frame->buf[0] = buf_ref;
+
+    sd = av_frame_new_side_data(frame, AV_FRAME_DATA_EPG_TABLE, sizeof(*table));
+    sd->data = (uint8_t*)table;
+
+    frame->pts = epg_ctx->pkt->pts;
+    frame->pkt_dts = epg_ctx->pkt->dts;
+    frame->pkt_size = epg_ctx->pkt->size;
+
+    av_packet_unref(epg_ctx->pkt);
+    return 0;
+
+fail:
+    av_packet_unref(epg_ctx->pkt);
+    av_epg_table_free(&table);
+    return AVERROR_INVALIDDATA;
+}
+
+static av_cold int decode_init(AVCodecContext *avctx)
+{
+    EPGContext *epg_ctx = avctx->priv_data;
+
+    for (int i = 0; i < 4; i++)
+        epg_ctx->infos[i].last_version = (-1);
+    epg_ctx->last_sched_table_id = EITS_START_TID;
+    epg_ctx->o_last_sched_table_id = OEITS_START_TID;
+
+    epg_ctx->pkt = av_packet_alloc();
+    return epg_ctx->pkt ? 0 : AVERROR(ENOMEM);
+}
+
+static av_cold int decode_end(AVCodecContext *avctx)
+{
+    EPGContext *epg_ctx = avctx->priv_data;
+    av_packet_free(&epg_ctx->pkt);
+    return 0;
+}
+
+static const AVClass epg_class = {
+    .class_name = "EPG Decoder",
+    .item_name  = av_default_item_name,
+    .version    = LIBAVUTIL_VERSION_INT,
+};
+
+AVCodec ff_epg_decoder = {
+    .name   = "epg",
+    .long_name  = NULL_IF_CONFIG_SMALL("EPG (Electronic Program Guide)"),
+    .type   = AVMEDIA_TYPE_DATA,
+    .id = AV_CODEC_ID_EPG,
+    .priv_data_size = sizeof(EPGContext),
+    .init = decode_init,
+    .close = decode_end,
+    .receive_frame = epg_receive_frame,
+    .priv_class = &epg_class,
+};
-- 
2.23.0