[FFmpeg-devel] [PATCH] avdevice/xcbgrab: Improve non-shm performance

[Kusanagi Kouichi]

On 2019-11-19 22:59:56 +0900, Kusanagi Kouichi wrote:
> Use AVBufferPool.
> 
> before:
> $ ffmpeg -benchmark -f x11grab -video_size 1920x1200 -r 200 -t 3 -i +0,0 -f null -
> ...
> frame=  600 fps=102 q=-0.0 Lsize=N/A time=00:00:03.00 bitrate=N/A speed=0.51x
> video:314kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
> bench: utime=1.551s stime=3.428s rtime=5.884s
> bench: maxrss=40132kB
> 
> after:
> $ ffmpeg -benchmark -f x11grab -video_size 1920x1200 -r 200 -t 3 -i +0,0 -f null -
> ...
> frame=  600 fps=138 q=-0.0 Lsize=N/A time=00:00:03.00 bitrate=N/A speed=0.69x
> video:314kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
> bench: utime=1.231s stime=2.407s rtime=4.349s
> bench: maxrss=40096kB
> 
> Signed-off-by: Kusanagi Kouichi <slash at ac.auone-net.jp>
> ---
>  libavdevice/xcbgrab.c | 38 +++++++++++++++++++++++++++++++-------
>  1 file changed, 31 insertions(+), 7 deletions(-)
> 
> diff --git a/libavdevice/xcbgrab.c b/libavdevice/xcbgrab.c
> index b7e689343e..fde9c534cd 100644
> --- a/libavdevice/xcbgrab.c
> +++ b/libavdevice/xcbgrab.c
> @@ -42,6 +42,7 @@
>  #include "libavutil/opt.h"
>  #include "libavutil/parseutils.h"
>  #include "libavutil/time.h"
> +#include "libavutil/buffer.h"
>  
>  #include "libavformat/avformat.h"
>  #include "libavformat/internal.h"
> @@ -71,6 +72,8 @@ typedef struct XCBGrabContext {
>      int region_border;
>      int centered;
>  
> +    AVBufferPool *buf_pool;
> +
>      const char *video_size;
>      const char *framerate;
>  
> @@ -146,6 +149,16 @@ static int xcbgrab_reposition(AVFormatContext *s,
>      return 0;
>  }
>  
> +static AVBufferRef *xcbgrab_allocate_buffer(const int size)
> +{
> +    AVPacket pkt;
> +
> +    if (av_new_packet(&pkt, size))
> +        return NULL;
> +
> +    return pkt.buf;
> +}
> +
>  static int xcbgrab_frame(AVFormatContext *s, AVPacket *pkt)
>  {
>      XCBGrabContext *c = s->priv_data;
> @@ -154,7 +167,7 @@ static int xcbgrab_frame(AVFormatContext *s, AVPacket *pkt)
>      xcb_drawable_t drawable = c->screen->root;
>      xcb_generic_error_t *e = NULL;
>      uint8_t *data;
> -    int length, ret;
> +    int length;
>  
>      iq  = xcb_get_image(c->conn, XCB_IMAGE_FORMAT_Z_PIXMAP, drawable,
>                          c->x, c->y, c->width, c->height, ~0);
> @@ -174,17 +187,21 @@ static int xcbgrab_frame(AVFormatContext *s, AVPacket *pkt)
>      if (!img)
>          return AVERROR(EAGAIN);
>  
> +    pkt->buf = av_buffer_pool_get(c->buf_pool);
> +    if (!pkt->buf) {
> +        free(img);
> +        return AVERROR(ENOMEM);
> +    }
> +
>      data   = xcb_get_image_data(img);
>      length = xcb_get_image_data_length(img);
>  
> -    ret = av_new_packet(pkt, length);
> -
> -    if (!ret)
> -        memcpy(pkt->data, data, length);
> -
> +    memcpy(pkt->buf->data, data, length);
>      free(img);
> +    pkt->data = pkt->buf->data;
> +    pkt->size = pkt->buf->size;
>  
> -    return ret;
> +    return 0;
>  }
>  
>  static void wait_frame(AVFormatContext *s, AVPacket *pkt)
> @@ -442,6 +459,7 @@ static av_cold int xcbgrab_read_close(AVFormatContext *s)
>  #endif
>  
>      xcb_disconnect(ctx->conn);
> +    av_buffer_pool_uninit(&ctx->buf_pool);
>  
>      return 0;
>  }
> @@ -665,6 +683,12 @@ static av_cold int xcbgrab_read_header(AVFormatContext *s)
>          return ret;
>      }
>  
> +    c->buf_pool = av_buffer_pool_init(c->frame_size, xcbgrab_allocate_buffer);
> +    if (ret < 0) {
> +        xcbgrab_read_close(s);
> +        return AVERROR(ENOMEM);
> +    }
> +
>  #if CONFIG_LIBXCB_SHM
>      if ((c->has_shm = check_shm(c->conn)))
>          c->segment = xcb_generate_id(c->conn);
> -- 
> 2.24.0
> 

ping