From 4a376f45ab58f29045be6df1af8121702299c701 Mon Sep 17 00:00:00 2001 From: Anton Khirnov Date: Sat, 30 Sep 2023 16:32:05 +0200 Subject: [PATCH] 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 --- libavcodec/mpegvideo_parser.c | 31 ++++++++++++++++++++++++++++--- 1 file changed, 28 insertions(+), 3 deletions(-) diff --git a/libavcodec/mpegvideo_parser.c b/libavcodec/mpegvideo_parser.c index 76cd2a5131..2cd0348317 100644 --- a/libavcodec/mpegvideo_parser.c +++ b/libavcodec/mpegvideo_parser.c @@ -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,