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lavc/mpegvideo_parser: improve exporting field-coding information 

* export AVCodecParserContext.picture_structure.
* when there are two field pictures in the packet, set
  the interlacing parameters accordingly:
        * repeat_pict=1 and picture_structure=FRAME to indicate 2 fields
        * field_order to indicate the first field of the two
This commit is contained in:
Anton Khirnov 2023-09-30 16:32:05 +02:00
parent 2c9eb49122
commit 4a376f45ab
1 changed files with 28 additions and 3 deletions
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31
libavcodec/mpegvideo_parser.c
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@ -111,9 +111,15 @@ static void mpegvideo_extract_headers(AVCodecParserContext *s,
int bit_rate = 0;
int vbv_delay = 0;
enum AVPixelFormat pix_fmt = AV_PIX_FMT_NONE;
//FIXME replace the crap with get_bits()
s->repeat_pict = 0;
// number of picture coding extensions (i.e. MPEG2 pictures)
// in this packet - should be 1 or 2
int nb_pic_ext = 0;
// when there are two pictures in the packet this indicates
// which field is in the first of them
int first_field = AV_FIELD_UNKNOWN;
//FIXME replace the crap with get_bits()
while (buf < buf_end) {
uint32_t start_code = -1;
buf= avpriv_find_start_code(buf, buf_end, &start_code);
@ -124,7 +130,6 @@ static void mpegvideo_extract_headers(AVCodecParserContext *s,
s->pict_type = (buf[1] >> 3) & 7;
if (bytes_left >= 4)
vbv_delay = ((buf[1] & 0x07) << 13) | (buf[2] << 5) | (buf[3] >> 3);
s->repeat_pict = 1;
}
break;
case SEQ_START_CODE:
@ -190,6 +195,7 @@ FF_ENABLE_DEPRECATION_WARNINGS
int progressive_frame = buf[4] & (1 << 7);
/* check if we must repeat the frame */
s->repeat_pict = 1;
if (repeat_first_field) {
if (pc->progressive_sequence) {
if (top_field_first)
@ -208,6 +214,19 @@ FF_ENABLE_DEPRECATION_WARNINGS
s->field_order = AV_FIELD_BB;
} else
s->field_order = AV_FIELD_PROGRESSIVE;
s->picture_structure = buf[2] & 3;
if (!nb_pic_ext) {
// remember parity of the first field for the case
// when there are 2 fields in packet
switch (s->picture_structure) {
case AV_PICTURE_STRUCTURE_BOTTOM_FIELD: first_field = AV_FIELD_BB; break;
case AV_PICTURE_STRUCTURE_TOP_FIELD: first_field = AV_FIELD_TT; break;
}
}
nb_pic_ext++;
}
break;
}
@ -243,6 +262,12 @@ FF_ENABLE_DEPRECATION_WARNINGS
s->coded_width = FFALIGN(pc->width, 16);
s->coded_height = FFALIGN(pc->height, 16);
}
if (avctx->codec_id == AV_CODEC_ID_MPEG1VIDEO || nb_pic_ext > 1) {
s->repeat_pict = 1;
s->picture_structure = AV_PICTURE_STRUCTURE_FRAME;
s->field_order = nb_pic_ext > 1 ? first_field : AV_FIELD_PROGRESSIVE;
}
}
static int mpegvideo_parse(AVCodecParserContext *s,