On 11/8/2024 10:51 PM, Pavel Koshevoy wrote:
I ran into segfaults in zimg when I attempted to use zscale to convert a 512x538@yuv444p16le(tv) image from HLG to Bt.709 with this filter chain:buffer=width=512:height=538:pix_fmt=yuv444p16le:time_base=1/1:sar=1/1,zscale=min=2020_ncl:rin=limited:pin=2020:tin=arib-std-b67:cin=left:t=linear,format=gbrpf32le,tonemap=gamma:desat=0,zscale=tin=linear:npl=100:p=709:m=709:r=limited:t=709,format=pix_fmts=yuv444p16le,buffersink I found several issues: - realign_frame called av_pix_fmt_count_planes with incorrect parameter. - av_frame_get_buffer did not align data pointers to specified alignment.
Because it's not supposed to. The align parameter doxy states "buffer size alignment", which is the result of aligning the stride/linesizes, not the data pointers.
You may want to use ff_default_get_video_buffer2(), which will add align amount of bytes to the allocated buffers (On top of aligning the linesizes to it), and then align the pointers with FFALIGN().
- s->tmp[job_nr] pointer was also unaligned.
Please split this into one patch per issue fixed, to simplify future bisecting.
https://github.com/sekrit-twc/zimg/issues/212 --- libavfilter/vf_zscale.c | 17 ++++++++++++----- libavutil/frame.c | 8 +++++++- 2 files changed, 19 insertions(+), 6 deletions(-) diff --git a/libavfilter/vf_zscale.c b/libavfilter/vf_zscale.c index 4ba059064b..a74a3da8d9 100644 --- a/libavfilter/vf_zscale.c +++ b/libavfilter/vf_zscale.c @@ -112,6 +112,7 @@ typedef struct ZScaleContext { int force_original_aspect_ratio;void *tmp[MAX_THREADS]; //separate for each thread;+ void *tmp_aligned[MAX_THREADS]; int nb_threads; int jobs_ret[MAX_THREADS]; double in_slice_start[MAX_THREADS]; @@ -594,6 +595,7 @@ static int graphs_build(AVFrame *in, AVFrame *out, const AVPixFmtDescriptor *des { ZScaleContext *s = ctx->priv; int ret; + int misaligned_tmp; size_t size; zimg_image_format src_format; zimg_image_format dst_format; @@ -628,11 +630,15 @@ static int graphs_build(AVFrame *in, AVFrame *out, const AVPixFmtDescriptor *des if (ret) return print_zimg_error(ctx);- if (s->tmp[job_nr])+ if (s->tmp[job_nr]) { av_freep(&s->tmp[job_nr]); - s->tmp[job_nr] = av_calloc(size, 1); + s->tmp_aligned[job_nr] = NULL; + } + s->tmp[job_nr] = av_calloc(size + ZIMG_ALIGNMENT - 1, 1); if (!s->tmp[job_nr]) return AVERROR(ENOMEM); + misaligned_tmp = ((uintptr_t)(s->tmp[job_nr])) % ZIMG_ALIGNMENT;
Use FFALIGN() instead.
OpenPGP_signature.asc
Description: OpenPGP digital signature
_______________________________________________ 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".
