When decoding a bitstream with weighted-bipred enabled, the results on ARM and x86 platforms may differ.
The reason for the inconsistency is that the value of STRIDE_ALIGN differs between platforms. And STRIDE_ALIGN is set to the buffer stride of temporary buffers for U and V components in mc_part_weighted. If the buffer stride is 32 or 64 (as on x86 platforms), the U and V pixels can be interleaved row by row without overlapping, resulting in correct output. However, on ARM platforms where the stride is 16, the V component will overwrite part of the U component's pixels, leading to incorrect predicted pixels. The bug can be reproduced by the following bitstream. https://trac.ffmpeg.org/attachment/ticket/11357/inter_weighted_bipred2.264 And the ref/fate file is also added in this patch. Fixes: ticket 11357 Signed-off-by: Bin Peng <peng...@visionular.com> --- libavcodec/utils.c | 4 ++- .../h264-conformance-weighted_bipred2.264 | 31 +++++++++++++++++++ 2 files changed, 34 insertions(+), 1 deletion(-) create mode 100644 tests/ref/fate/h264-conformance-weighted_bipred2.264 diff --git a/libavcodec/utils.c b/libavcodec/utils.c index 90867ed6b1..5d15f5c8fa 100644 --- a/libavcodec/utils.c +++ b/libavcodec/utils.c @@ -144,6 +144,7 @@ void avcodec_align_dimensions2(AVCodecContext *s, int *width, int *height, int i; int w_align = 1; int h_align = 1; + int stride_align = STRIDE_ALIGN; AVPixFmtDescriptor const *desc = av_pix_fmt_desc_get(s->pix_fmt); if (desc) { @@ -339,13 +340,14 @@ void avcodec_align_dimensions2(AVCodecContext *s, int *width, int *height, // increasing witdth ensure that the temporary area is large enough, // the next rounded up width is 32 *width = FFMAX(*width, 32); + stride_align = FFMAX(stride_align, 32); } if (s->codec_id == AV_CODEC_ID_SVQ3) { *width = FFMAX(*width, 32); } for (i = 0; i < 4; i++) - linesize_align[i] = STRIDE_ALIGN; + linesize_align[i] = stride_align; } void avcodec_align_dimensions(AVCodecContext *s, int *width, int *height) diff --git a/tests/ref/fate/h264-conformance-weighted_bipred2.264 b/tests/ref/fate/h264-conformance-weighted_bipred2.264 new file mode 100644 index 0000000000..1d9bf90d12 --- /dev/null +++ b/tests/ref/fate/h264-conformance-weighted_bipred2.264 @@ -0,0 +1,31 @@ +#software: Lavf61.1.100 +#tb 0: 1/24 +#media_type 0: video +#codec_id 0: rawvideo +#dimensions 0: 32x168 +#sar 0: 0/1 +0, 0, 0, 2, 8064, 0x836abac1 +0, 2, 2, 2, 8064, 0x836abac1 +0, 4, 4, 2, 8064, 0x836abac1 +0, 6, 6, 2, 8064, 0x836abac1 +0, 8, 8, 2, 8064, 0x836abac1 +0, 10, 10, 2, 8064, 0x5fc56e41 +0, 12, 12, 2, 8064, 0x5fc56e41 +0, 14, 14, 2, 8064, 0x5fc56e41 +0, 16, 16, 2, 8064, 0x5fc56e41 +0, 18, 18, 2, 8064, 0x5fc56e41 +0, 20, 20, 2, 8064, 0xbfbb8282 +0, 22, 22, 2, 8064, 0xbfbb8282 +0, 24, 24, 2, 8064, 0x4cbc7d64 +0, 26, 26, 2, 8064, 0x5eaf7bd3 +0, 28, 28, 2, 8064, 0x43956bb8 +0, 30, 30, 2, 8064, 0x047a0f2d +0, 32, 32, 2, 8064, 0x0d271111 +0, 34, 34, 2, 8064, 0xab421086 +0, 36, 36, 2, 8064, 0x00780fcb +0, 38, 38, 2, 8064, 0xfd2513c0 +0, 40, 40, 2, 8064, 0xa10b5ae7 +0, 42, 42, 2, 8064, 0xa10b5ae7 +0, 44, 44, 2, 8064, 0xa10b5ae7 +0, 46, 46, 2, 8064, 0xa10b5ae7 +0, 48, 48, 2, 8064, 0xa10b5ae7 -- 2.25.1 _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
