diff --git a/source/blender/imbuf/intern/anim_movie.c b/source/blender/imbuf/intern/anim_movie.c --- a/source/blender/imbuf/intern/anim_movie.c +++ b/source/blender/imbuf/intern/anim_movie.c @@ -1205,7 +1205,29 @@ } IMB_freeImBuf(anim->last_frame); - anim->last_frame = IMB_allocImBuf(anim->x, anim->y, 32, IB_rect); + + /* Certain versions of FFmpeg have a bug in libswscale which ends up in crash + * when destination buffer is not properly aligned. For example, this happens + * in FFmpeg 4.3.1. It got fixed later on, but for compatibility reasons is + * still best to avoid crash. + * + * This is achieved by using own allocation call rather than relying on + * IMB_allocImBuf() to do so since the IMB_allocImBuf() is not guaranteed + * to perform aligned allocation. + * + * In theory this could give better performance, since SIMD operations on + * aligned data are usually faster. + * + * Note that even though sometimes vertical flip is required it does not + * affect on alignment of data passed to sws_scale because if the X dimension + * is not 32 byte aligned special intermediate buffer is allocated. + * + * The issue was reported to FFmpeg under ticket #8747 in the FFmpeg tracker + * and is fixed in the newer versions than 4.3.1. */ + anim->last_frame = IMB_allocImBuf(anim->x, anim->y, 32, 0); + anim->last_frame->rect = MEM_mallocN_aligned((size_t)4 * anim->x * anim->y, 32, "ffmpeg ibuf"); + anim->last_frame->mall |= IB_rect; + anim->last_frame->rect_colorspace = colormanage_colorspace_get_named(anim->colorspace); ffmpeg_postprocess(anim);