From a42a9c12dfbbb6f60d20c2d05ff87a0ce2cf7ebf Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?J=C3=A9r=C3=B4me=20Gorin?= Date: Mon, 10 Feb 2025 10:15:13 +0100 Subject: [PATCH] Fix h261 I frame detection --- libavcodec/h261dec.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/libavcodec/h261dec.c b/libavcodec/h261dec.c index cabca33c8d..3bc20ef900 100644 --- a/libavcodec/h261dec.c +++ b/libavcodec/h261dec.c @@ -457,7 +457,7 @@ intra: static int h261_decode_picture_header(H261DecContext *h) { MpegEncContext *const s = &h->s; - int format, i; + int format, i, intra_flag; uint32_t startcode = 0; for (i = get_bits_left(&s->gb); i > 24; i -= 1) { @@ -478,8 +478,14 @@ static int h261_decode_picture_header(H261DecContext *h) /* PTYPE starts here */ skip_bits1(&s->gb); /* split screen off */ skip_bits1(&s->gb); /* camera off */ - skip_bits1(&s->gb); /* freeze picture release off */ + intra_flag = get_bits1(&s->gb); /* Intra 1 = I-frame, 0 = P-frame */ + if (intra_flag){ + s->pict_type = AV_PICTURE_TYPE_I; + }else{ + s->pict_type = AV_PICTURE_TYPE_P; + } + format = get_bits1(&s->gb); // only 2 formats possible @@ -498,10 +504,8 @@ static int h261_decode_picture_header(H261DecContext *h) if (skip_1stop_8data_bits(&s->gb) < 0) return AVERROR_INVALIDDATA; - /* H.261 has no I-frames, but if we pass AV_PICTURE_TYPE_I for the first - * frame, the codec crashes if it does not contain all I-blocks - * (e.g. when a packet is lost). */ - s->pict_type = AV_PICTURE_TYPE_P; + + h->gob_number = 0; return 0; -- 2.39.5 (Apple Git-154)