From 8ca4b515e73079cda068e253853654db394b8171 Mon Sep 17 00:00:00 2001 From: Andreas Rheinhardt Date: Sat, 29 Jan 2022 22:39:15 +0100 Subject: [PATCH] avcodec/mpegvideo_enc: Allow slices only for slice-thread-able codecs One can use slices without slice-threading. The results for mpegvideo-encoders are abysmal: AMV, SpeedHQ, H.263, RV10, RV20, MSMPEG4v2, MSMPEG4v3 and WMV1 produce broken files. WMV2 meanwhile expects the MpegEncContext given to ff_wmv2_encode_mb() to be at the beginning of a Wmv2Context (a structure that this encoder shares with the WMV2 decoder), yet this is only true for the main context and not for the slice contexts, leading to segfaults. SpeedHQ additionally triggers an av_assert2, because it is not byte-aligned at a position where it ought to be byte-aligned. Given that no codec not supporting slice threading works this commit disallows using slices unless the encoder supports slice threading. Signed-off-by: Andreas Rheinhardt --- libavcodec/mpegvideo_enc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libavcodec/mpegvideo_enc.c b/libavcodec/mpegvideo_enc.c index 71c999fab0..5abd463430 100644 --- a/libavcodec/mpegvideo_enc.c +++ b/libavcodec/mpegvideo_enc.c @@ -603,7 +603,7 @@ av_cold int ff_mpv_encode_init(AVCodecContext *avctx) } if (avctx->slices > 1 && - (avctx->codec_id == AV_CODEC_ID_FLV1 || avctx->codec_id == AV_CODEC_ID_H261)) { + !(avctx->codec->capabilities & AV_CODEC_CAP_SLICE_THREADS)) { av_log(avctx, AV_LOG_ERROR, "Multiple slices are not supported by this codec\n"); return AVERROR(EINVAL); }