On 1/4/2019 7:07 PM, Michael Niedermayer wrote:
> Fixes: Timeout
> Fixes:
> 10709/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_H264_fuzzer-5630617975259136
>
> Before change: Executed
> clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_H264_fuzzer-5630617975259136
> in 28285 ms
> After change: Executed
> clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_H264_fuzzer-5630617975259136
> in 9395 ms
>
> Found-by: continuous fuzzing process
> https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc>
> ---
> libavcodec/utils.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/libavcodec/utils.c b/libavcodec/utils.c
> index d519b16092..963924a9ca 100644
> --- a/libavcodec/utils.c
> +++ b/libavcodec/utils.c
> @@ -423,8 +423,12 @@ void ff_color_frame(AVFrame *frame, const int c[4])
> int height = is_chroma ? AV_CEIL_RSHIFT(frame->height,
> desc->log2_chroma_h) : frame->height;
> for (y = 0; y < height; y++) {
> if (desc->comp[0].depth >= 9) {
> - for (x = 0; x<bytes; x++)
> - ((uint16_t*)dst)[x] = c[p];
> + if (!y) {
> + for (x = 0; x<bytes; x++)
> + ((uint16_t*)dst)[x] = c[p];
> + } else {
> + memcpy(dst, frame->data[p], 2*bytes);
I think it would be cleaner if you instead rewrite the loop. Something like:
> for (p = 0; p<desc->nb_components; p++) {
> uint8_t *dst = frame->data[p];
> int is_chroma = p == 1 || p == 2;
> int hbd = desc->comp[0].depth >= 9;
> int bytes = is_chroma ? AV_CEIL_RSHIFT(frame->width,
> desc->log2_chroma_w) : frame->width;
> int height = is_chroma ? AV_CEIL_RSHIFT(frame->height,
> desc->log2_chroma_h) : frame->height;
> if (hbd) {
> for (x = 0; x < bytes; x++)
> ((uint16_t*)dst)[x] = c[p];
> } else
> memset(dst, c[p], bytes);
> bytes <<= hbd;
> for (y = 1; y < height; y++) {
> memcpy(dst, frame->data[p], bytes);
> dst += frame->linesize[p];
> }
> }
Not sure if replacing the memset with memcpy for the 8bit case is faster
or not, but the removal of the branch should help in any case.
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