From 5cdce56a79510284271f6b2eeb2231ff6a2bc7fd Mon Sep 17 00:00:00 2001 From: Andreas Rheinhardt Date: Sat, 14 Jun 2025 01:48:55 +0200 Subject: [PATCH] avcodec/mpegvideo: Reduce stack usage when copying MpegEncContext (GCC did not perform this on its own; Clang did.) Signed-off-by: Andreas Rheinhardt --- libavcodec/mpegvideo.c | 29 +++++++++++++---------------- 1 file changed, 13 insertions(+), 16 deletions(-) diff --git a/libavcodec/mpegvideo.c b/libavcodec/mpegvideo.c index 4701267d81..ff2703f487 100644 --- a/libavcodec/mpegvideo.c +++ b/libavcodec/mpegvideo.c @@ -171,27 +171,24 @@ static av_cold void free_duplicate_contexts(MpegEncContext *s) free_duplicate_context(s); } -static void backup_duplicate_context(MpegEncContext *bak, MpegEncContext *src) -{ -#define COPY(a) bak->a = src->a - COPY(sc); - COPY(blocks); - COPY(block); - COPY(start_mb_y); - COPY(end_mb_y); - COPY(dc_val); - COPY(ac_val); -#undef COPY -} - int ff_update_duplicate_context(MpegEncContext *dst, const MpegEncContext *src) { - MpegEncContext bak; +#define COPY(M) \ + M(ScratchpadContext, sc) \ + M(void*, blocks) \ + M(void*, block) \ + M(int, start_mb_y) \ + M(int, end_mb_y) \ + M(int16_t*, dc_val) \ + M(void*, ac_val) + int ret; // FIXME copy only needed parts - backup_duplicate_context(&bak, dst); +#define BACKUP(T, member) T member = dst->member; + COPY(BACKUP) memcpy(dst, src, sizeof(MpegEncContext)); - backup_duplicate_context(dst, &bak); +#define RESTORE(T, member) dst->member = member; + COPY(RESTORE) ret = ff_mpv_framesize_alloc(dst->avctx, &dst->sc, dst->linesize); if (ret < 0) {