[FFmpeg-devel,v4,2/4] lavc/avs3_parser: add avs3 parser

diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 3431ba2dca..5c031f7777 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -1059,6 +1059,7 @@  OBJS-$(CONFIG_AC3_PARSER)              += ac3tab.o aac_ac3_parser.o
 OBJS-$(CONFIG_ADX_PARSER)              += adx_parser.o adx.o
 OBJS-$(CONFIG_AV1_PARSER)              += av1_parser.o av1_parse.o
 OBJS-$(CONFIG_AVS2_PARSER)             += avs2_parser.o
+OBJS-$(CONFIG_AVS3_PARSER)             += avs3_parser.o
 OBJS-$(CONFIG_BMP_PARSER)              += bmp_parser.o
 OBJS-$(CONFIG_CAVSVIDEO_PARSER)        += cavs_parser.o
 OBJS-$(CONFIG_COOK_PARSER)             += cook_parser.o
diff --git a/libavcodec/avs3_parser.c b/libavcodec/avs3_parser.c
new file mode 100644
index 0000000000..f04f696a89
--- /dev/null
+++ b/libavcodec/avs3_parser.c
@@ -0,0 +1,179 @@ 
+/*
+ * AVS3-P2/IEEE1857.10 video parser.
+ * Copyright (c) 2020 Zhenyu Wang <wangzhenyu@pkusz.edu.cn>
+ *                    Bingjie Han <hanbj@pkusz.edu.cn>
+ *                    Huiwen Ren  <hwrenx@gmail.com>
+ *
+ * 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 "avs3_parser.h"
+#include "get_bits.h"
+
+static int avs3_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size)
+{
+    int pic_found  = pc->frame_start_found;
+    uint32_t state = pc->state;
+    int cur = 0;
+
+    if (!pic_found) {
+        for (; cur < buf_size; ++cur) {
+            state = (state << 8) | buf[cur];
+            if (ISPIC(buf[cur])){
+                ++cur;
+                pic_found = 1;
+                break;
+            }
+        }
+    }
+
+    if (pic_found) {
+        if (!buf_size)
+            return END_NOT_FOUND;
+        for (; cur < buf_size; ++cur) {
+            state = (state << 8) | buf[cur];
+            if ((state & 0xFFFFFF00) == 0x100 && ISUNIT(state & 0xFF)) {
+                pc->frame_start_found = 0;
+                pc->state = -1;
+                return cur - 3;
+            }
+        }
+    }
+
+    pc->frame_start_found = pic_found;
+    pc->state = state;
+
+    return END_NOT_FOUND;
+}
+
+static void parse_avs3_nal_units(AVCodecParserContext *s, const uint8_t *buf,
+                           int buf_size, AVCodecContext *avctx)
+{
+    if (buf_size < 5) {
+        return;
+    }
+
+    if (buf[0] == 0x0 && buf[1] == 0x0 && buf[2] == 0x1) {
+        if (buf[3] == AVS3_SEQ_START_CODE) {
+            GetBitContext gb;
+            int profile, ratecode;
+
+            init_get_bits(&gb, buf + 4, buf_size - 4);
+
+            s->key_frame = 1;
+            s->pict_type = AV_PICTURE_TYPE_I;
+
+            profile = get_bits(&gb, 8);
+            // Skip bits: level(8)
+            //            progressive(1)
+            //            field(1)
+            //            library(2)
+            //            resv(1)
+            //            width(14)
+            //            resv(1)
+            //            height(14)
+            //            chroma(2)
+            //            sampe_precision(3)
+            skip_bits(&gb, 47);
+
+            if (profile == AVS3_PROFILE_BASELINE_MAIN10) {
+                int sample_precision = get_bits(&gb, 3);
+                if (sample_precision == 1) {
+                    avctx->pix_fmt = AV_PIX_FMT_YUV420P;
+                } else if (sample_precision == 2) {
+                    avctx->pix_fmt = AV_PIX_FMT_YUV420P10LE;
+                } else {
+                    avctx->pix_fmt = AV_PIX_FMT_NONE;
+                }
+            }
+
+            // Skip bits: resv(1)
+            //            aspect(4)
+            skip_bits(&gb, 5);
+
+            ratecode = get_bits(&gb, 4);
+
+            // Skip bits: resv(1)
+            //            bitrate_low(18)
+            //            resv(1)
+            //            bitrate_high(12)
+            //            low_delay
+            skip_bits(&gb, 32);
+
+            avctx->has_b_frames = !get_bits(&gb, 1);
+
+            avctx->framerate.num = avctx->time_base.den = avs3_frame_rate_tab[ratecode].num;
+            avctx->framerate.den = avctx->time_base.num = avs3_frame_rate_tab[ratecode].den;
+
+            s->width  = s->coded_width = avctx->width;
+            s->height = s->coded_height = avctx->height;
+
+            av_log(avctx, AV_LOG_DEBUG,
+                       "avs3 parse seq hdr: profile %d; coded wxh: %dx%d; "
+                       "frame_rate_code %d\n", profile, avctx->width, avctx->height, ratecode);
+
+        } else if (buf[3] == AVS3_INTRA_PIC_START_CODE) {
+            s->key_frame = 1;
+            s->pict_type = AV_PICTURE_TYPE_I;
+        } else if (buf[3] == AVS3_INTER_PIC_START_CODE){
+            s->key_frame = 0;
+            if (buf_size > 9) {
+                int pic_code_type = buf[8] & 0x3;
+                if (pic_code_type == 1 || pic_code_type == 3) {
+                    s->pict_type = AV_PICTURE_TYPE_P;
+                } else {
+                    s->pict_type = AV_PICTURE_TYPE_B;
+                }
+            }
+        }
+    }
+}
+
+
+static int avs3_parse(AVCodecParserContext *s, AVCodecContext *avctx,
+                      const uint8_t **poutbuf, int *poutbuf_size,
+                      const uint8_t *buf, int buf_size)
+{
+    ParseContext *pc = s->priv_data;
+    int next;
+
+    if (s->flags & PARSER_FLAG_COMPLETE_FRAMES)  {
+        next = buf_size;
+    } else {
+        next = avs3_find_frame_end(pc, buf, buf_size);
+        if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
+            *poutbuf = NULL;
+            *poutbuf_size = 0;
+            return buf_size;
+        }
+    }
+
+    parse_avs3_nal_units(s, buf, buf_size, avctx);
+
+    *poutbuf = buf;
+    *poutbuf_size = buf_size;
+
+    return next;
+}
+
+AVCodecParser ff_avs3_parser = {
+    .codec_ids      = { AV_CODEC_ID_AVS3 },
+    .priv_data_size = sizeof(ParseContext),
+    .parser_parse   = avs3_parse,
+    .parser_close   = ff_parse_close,
+    .split          = ff_mpeg4video_split,
+};
diff --git a/libavcodec/avs3_parser.h b/libavcodec/avs3_parser.h
new file mode 100644
index 0000000000..afc6d235b9
--- /dev/null
+++ b/libavcodec/avs3_parser.h
@@ -0,0 +1,64 @@ 
+/*
+ * AVS3-P2/IEEE1857.10 video parser.
+ * Copyright (c) 2020 Zhenyu Wang <wangzhenyu@pkusz.edu.cn>
+ *                    Bingjie Han <hanbj@pkusz.edu.cn>
+ *                    Huiwen Ren  <hwrenx@gmail.com>
+ *
+ * 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
+ */
+
+#ifndef AVCODEC_AVS3PARSER_H
+#define AVCODEC_AVS3PARSER_H
+
+#include "parser.h"
+
+#define AVS3_NAL_START_CODE          0x010000
+#define AVS3_SEQ_START_CODE          0xB0
+#define AVS3_SEQ_END_CODE            0xB1
+#define AVS3_USER_DATA_START_CODE    0xB2
+#define AVS3_INTRA_PIC_START_CODE    0xB3
+#define AVS3_UNDEF_START_CODE        0xB4
+#define AVS3_EXTENSION_START_CODE    0xB5
+#define AVS3_INTER_PIC_START_CODE    0xB6
+#define AVS3_VIDEO_EDIT_CODE         0xB7
+#define AVS3_FIRST_SLICE_START_CODE  0x00
+#define AVS3_PROFILE_BASELINE_MAIN   0x20
+#define AVS3_PROFILE_BASELINE_MAIN10 0x22
+
+#define ISPIC(x) ((x) == AVS3_INTRA_PIC_START_CODE || (x) == AVS3_INTER_PIC_START_CODE)
+#define ISUNIT(x) ((x) == AVS3_SEQ_START_CODE || ISPIC(x))
+
+static const AVRational avs3_frame_rate_tab[16] = {
+    { 0    , 0   }, // forbid
+    { 24000, 1001},
+    { 24   , 1   },
+    { 25   , 1   },
+    { 30000, 1001},
+    { 30   , 1   },
+    { 50   , 1   },
+    { 60000, 1001},
+    { 60   , 1   },
+    { 100  , 1   },
+    { 120  , 1   },
+    { 200  , 1   },
+    { 240  , 1   },
+    { 300  , 1   },
+    { 0    , 0   }, // reserved
+    { 0    , 0   }  // reserved
+};
+
+#endif /* AVCODEC_AVS3PARSER_H */
diff --git a/libavcodec/parsers.c b/libavcodec/parsers.c
index 7d75cea830..aab1d5e3e5 100644
--- a/libavcodec/parsers.c
+++ b/libavcodec/parsers.c
@@ -28,6 +28,7 @@  extern AVCodecParser ff_ac3_parser;
 extern AVCodecParser ff_adx_parser;
 extern AVCodecParser ff_av1_parser;
 extern AVCodecParser ff_avs2_parser;
+extern AVCodecParser ff_avs3_parser;
 extern AVCodecParser ff_bmp_parser;
 extern AVCodecParser ff_cavsvideo_parser;
 extern AVCodecParser ff_cook_parser;