[FFmpeg-devel] [PATCH v2 2/2] avcodec/v210dec: add the frame and slice threading support

Michael Niedermayer michael at niedermayer.cc
Fri Sep 20 20:57:10 EEST 2019


On Fri, Sep 06, 2019 at 11:28:29PM +0800, lance.lmwang at gmail.com wrote:
> From: Limin Wang <lance.lmwang at gmail.com>
> 
> The multithread is avoid one core cpu is full with other filter like scale etc.
> About the performance, the gain is very small, below is my testing for
> performance.
> In order to avoid the disk bottleneck, I'll use stream_loop mode for 10 frame
> only.
> 
> ./ffmpeg -y -i ~/Movies/4k_Rec709_ProResHQ.mov -c:v v210 -f rawvideo -frames 10
> ~/Movies/1.v210
> 
> master:
> ./ffmpeg -threads 1 -s 4096x3072 -stream_loop 100 -i ~/Movies/1.v210 -benchmark
> -f null -
> frame= 1010 fps= 42 q=-0.0 Lsize=N/A time=00:00:40.40 bitrate=N/A speed=1.69x
> video:529kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing
> overhead: unknown
> bench: utime=10.082s stime=13.784s rtime=23.889s
> bench: maxrss=147836928kB
> 
> patch applied:
> ./ffmpeg -threads 4 -thread_type frame+slice  -s 4096x3072 -stream_loop 100 -i
> ~/Movies/1.v210 -benchmark -f null -
> 
> frame= 1010 fps= 55 q=-0.0 Lsize=N/A time=00:00:40.40 bitrate=N/A speed=2.22x
> video:529kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing
> overhead: unknown
> bench: utime=11.407s stime=17.258s rtime=18.279s
> bench: maxrss=442884096kB
> 
> Signed-off-by: Limin Wang <lance.lmwang at gmail.com>
> ---
>  libavcodec/v210dec.c | 135 +++++++++++++++++++++++++++++++++------------------
>  libavcodec/v210dec.h |   1 +
>  2 files changed, 88 insertions(+), 48 deletions(-)
> 
> diff --git a/libavcodec/v210dec.c b/libavcodec/v210dec.c
> index 6ce18aa..2cdb99e 100644
> --- a/libavcodec/v210dec.c
> +++ b/libavcodec/v210dec.c
> @@ -28,6 +28,7 @@
>  #include "libavutil/internal.h"
>  #include "libavutil/mem.h"
>  #include "libavutil/intreadwrite.h"
> +#include "thread.h"
>  
>  #define READ_PIXELS(a, b, c)         \
>      do {                             \
> @@ -37,6 +38,13 @@
>          *c++ = (val >> 20) & 0x3FF;  \
>      } while (0)
>  
> +#define MAX_SLICES 32
> +typedef struct ThreadData {
> +    AVFrame *frame;
> +    uint8_t *buf;
> +    int stride;
> +} ThreadData;
> +
>  static void v210_planar_unpack_c(const uint32_t *src, uint16_t *y, uint16_t *u, uint16_t *v, int width)
>  {
>      uint32_t val;
> @@ -67,58 +75,32 @@ static av_cold int decode_init(AVCodecContext *avctx)
>      s->aligned_input = 0;
>      ff_v210dec_init(s);
>  
> +    s->slice_count = av_clip(avctx->thread_count, 1, MAX_SLICES);

why is there a MAX_SLICES ?


[...]
> @@ -193,6 +228,10 @@ AVCodec ff_v210_decoder = {
>      .priv_data_size = sizeof(V210DecContext),
>      .init           = decode_init,
>      .decode         = decode_frame,
> -    .capabilities   = AV_CODEC_CAP_DR1,
> +    .capabilities   = AV_CODEC_CAP_DR1 |
> +                      AV_CODEC_CAP_SLICE_THREADS |
> +                      AV_CODEC_CAP_FRAME_THREADS,
>      .priv_class     = &v210dec_class,

> +    .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE |
> +                      FF_CODEC_CAP_INIT_CLEANUP,

This appears unrelated and if so should be in a seperate patch

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

You can kill me, but you cannot change the truth.
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