Commit: 6778ef4dcc6e8d92e3b2ec9b9ecaf1e54e5bf7b5 Author: Sergey Sharybin Date: Mon Jul 20 18:57:28 2020 +0200 Branches: master https://developer.blender.org/rB6778ef4dcc6e8d92e3b2ec9b9ecaf1e54e5bf7b5
Fix T78867: Crash related to viewing video files Any time FFmpeg was used to get a picture Blender would crash when FFmpeg 4.3 is used. This affects thumbnails, VSE, Clip Editor. Caused by a bug in FFmpeg which lead to crashes when unaligned buffer was passed to sws_scale(). It got fixed later on in FFmpeg, but for portability and compatibility reasons still nice to avoid crash, especially since it's not so difficult to do. FFmpeg ticked number is #8747 The FFmpeg Git hash with the fix: ba3e771a42c2 Differential Revision: https://developer.blender.org/D8355 =================================================================== M source/blender/imbuf/intern/anim_movie.c =================================================================== diff --git a/source/blender/imbuf/intern/anim_movie.c b/source/blender/imbuf/intern/anim_movie.c index 8361c43afc1..9fab450cc76 100644 --- a/source/blender/imbuf/intern/anim_movie.c +++ b/source/blender/imbuf/intern/anim_movie.c @@ -1205,7 +1205,29 @@ static ImBuf *ffmpeg_fetchibuf(struct anim *anim, int position, IMB_Timecode_Typ } 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); _______________________________________________ Bf-blender-cvs mailing list [email protected] https://lists.blender.org/mailman/listinfo/bf-blender-cvs
