On Thu, Jan 5, 2023 at 6:42 PM Dmitrii Ovchinnikov
<ovchinnikov.dmit...@gmail.com> wrote:
>
> From: Dmitrii Ovchinnikov <ovchinnikov.dmit...@gmail.com>
>
> This change improves the performance and multicore
> scalability of the vp9 codec for streaming single-pass encoded videos. The
> current thread limit for ffmpeg codecs is 16 (MAX_AUTO_THREADS in
> pthread_internal.h) due to a limitation in H.264 codec that prevents more
> than 16 threads being used.
>
> Increasing the thread limit to 64 for vp9 improves
> the performance for encoding 4K raw videos for streaming by up to 47%
> compared to 16 threads, and from 20-30% for 32 threads, with the same quality
> as measured by the VMAF score.
>
> Did not need to add a check for limit in libvpx as it is already present
> in libvpx/vp9/vp9_cx_iface.c:
> RANGE_CHECK_HI(cfg, g_threads, 64);
> As demonstrated by following message when -threads is set to anything more
> than 64
> [libvpx-vp9 @ 0x30ed380] Additional information: g_threads out of range
> [..64]
>
> ---
> libavcodec/libvpxdec.c | 2 +-
> libavcodec/libvpxenc.c | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/libavcodec/libvpxdec.c b/libavcodec/libvpxdec.c
> index 9cd2c56caf..19407092d0 100644
> --- a/libavcodec/libvpxdec.c
> +++ b/libavcodec/libvpxdec.c
> @@ -88,7 +88,7 @@ static av_cold int vpx_init(AVCodecContext *avctx,
> const struct vpx_codec_iface *iface)
> {
> struct vpx_codec_dec_cfg deccfg = {
> - .threads = FFMIN(avctx->thread_count ? avctx->thread_count :
> av_cpu_count(), 16)
> + .threads = avctx->thread_count ? avctx->thread_count : av_cpu_count()
> };
>
> av_log(avctx, AV_LOG_INFO, "%s\n", vpx_codec_version_str());
> diff --git a/libavcodec/libvpxenc.c b/libavcodec/libvpxenc.c
> index 9aa5510c28..0627e13973 100644
> --- a/libavcodec/libvpxenc.c
> +++ b/libavcodec/libvpxenc.c
> @@ -942,7 +942,7 @@ static av_cold int vpx_init(AVCodecContext *avctx,
> enccfg.g_timebase.num = avctx->time_base.num;
> enccfg.g_timebase.den = avctx->time_base.den;
> enccfg.g_threads =
> - FFMIN(avctx->thread_count ? avctx->thread_count : av_cpu_count(),
> 16);
> + avctx->thread_count ? avctx->thread_count : av_cpu_count();
> enccfg.g_lag_in_frames= ctx->lag_in_frames;
>
Do you check the change with the old version libvpx? as I know, older
versions libvpx setting the number of threads higher than 16 will
cause a crash, so I think at least a version check needs to be added
> if (avctx->flags & AV_CODEC_FLAG_PASS1)
> --
> 2.38.1.windows.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".
