PR #21537 opened by michaelni URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/21537 Patch URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/21537.patch
Fixes: out of array access Found-by: Zhenpeng (Leo) Lin from depthfirst Signed-off-by: Michael Niedermayer <[email protected]> >From 02b52593d6a6498cc967904c6faa6477c0682a16 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer <[email protected]> Date: Wed, 21 Jan 2026 02:31:51 +0100 Subject: [PATCH] avcodec/mpegvideo_enc: Restructure ff_h263_encode_gob_header() relation to update_mb_info() Fixes: out of array access Found-by: Zhenpeng (Leo) Lin from depthfirst Signed-off-by: Michael Niedermayer <[email protected]> --- libavcodec/mpegvideo_enc.c | 17 ++++++----------- 1 file changed, 6 insertions(+), 11 deletions(-) diff --git a/libavcodec/mpegvideo_enc.c b/libavcodec/mpegvideo_enc.c index a4f78c25db..1714d3b6db 100644 --- a/libavcodec/mpegvideo_enc.c +++ b/libavcodec/mpegvideo_enc.c @@ -2925,7 +2925,7 @@ static void write_mb_info(MPVEncContext *const s) bytestream_put_byte(&ptr, 0); /* vmv2 */ } -static void update_mb_info(MPVEncContext *const s, int startcode) +static void update_mb_info(MPVEncContext *const s) { if (!s->mb_info) return; @@ -2933,14 +2933,6 @@ static void update_mb_info(MPVEncContext *const s, int startcode) s->mb_info_size += 12; s->prev_mb_info = s->last_mb_info; } - if (startcode) { - s->prev_mb_info = put_bytes_count(&s->pb, 0); - /* This might have incremented mb_info_size above, and we return without - * actually writing any info into that slot yet. But in that case, - * this will be called again at the start of the after writing the - * start code, actually writing the mb info. */ - return; - } s->last_mb_info = put_bytes_count(&s->pb, 0); if (!s->mb_info_size) @@ -3154,8 +3146,11 @@ static int encode_thread(AVCodecContext *c, void *arg){ #endif case AV_CODEC_ID_H263: if (CONFIG_H263_ENCODER) { - update_mb_info(s, 1); + if (s->mb_info && put_bytes_count(&s->pb, 0) - s->prev_mb_info >= s->mb_info) + s->mb_info_size += 12; + ff_h263_encode_gob_header(s, mb_y); + s->prev_mb_info = put_bits_count(&s->pb)/8; } break; } @@ -3180,7 +3175,7 @@ static int encode_thread(AVCodecContext *c, void *arg){ s->c.mb_skipped = 0; s->dquant=0; //only for QP_RD - update_mb_info(s, 0); + update_mb_info(s); if (mb_type & (mb_type-1) || (s->mpv_flags & FF_MPV_FLAG_QP_RD)) { // more than 1 MB type possible or FF_MPV_FLAG_QP_RD int next_block=0; -- 2.52.0 _______________________________________________ ffmpeg-devel mailing list -- [email protected] To unsubscribe send an email to [email protected]
