[FFmpeg-devel] [PATCH 2/2] avcodec/libdav1d: use a custom picture allocator

[Vittorio Giovara]

On Mon, Mar 4, 2019 at 4:08 PM James Almer <jamrial at gmail.com> wrote:

> Replaces the libdav1d internal allocator. It uses an AVBufferPool to
> reduce the
> amount of allocated buffers.
> About 5% speed up when decoding 720p or higher streams.
>
> Signed-off-by: James Almer <jamrial at gmail.com>
> ---
> get_buffer2() can't be used for this decoder, as there's no guarantee the
> buffers
> it returns will respect the constrains specified by libdav1d.
>
>  libavcodec/libdav1d.c | 72 ++++++++++++++++++++++++++++++++++++++-----
>  1 file changed, 65 insertions(+), 7 deletions(-)
>
> diff --git a/libavcodec/libdav1d.c b/libavcodec/libdav1d.c
> index 459bbae687..855c27db7f 100644
> --- a/libavcodec/libdav1d.c
> +++ b/libavcodec/libdav1d.c
> @@ -22,6 +22,7 @@
>  #include <dav1d/dav1d.h>
>
>  #include "libavutil/avassert.h"
> +#include "libavutil/imgutils.h"
>  #include "libavutil/opt.h"
>
>  #include "avcodec.h"
> @@ -31,12 +32,21 @@
>  typedef struct Libdav1dContext {
>      AVClass *class;
>      Dav1dContext *c;
> +    AVBufferPool *pool;
> +    int pool_size;
>
>      Dav1dData data;
>      int tile_threads;
>      int apply_grain;
>  } Libdav1dContext;
>
> +static const enum AVPixelFormat pix_fmt[][3] = {
> +    [DAV1D_PIXEL_LAYOUT_I400] = { AV_PIX_FMT_GRAY8,   AV_PIX_FMT_GRAY10,
>   AV_PIX_FMT_GRAY12 },
> +    [DAV1D_PIXEL_LAYOUT_I420] = { AV_PIX_FMT_YUV420P,
> AV_PIX_FMT_YUV420P10, AV_PIX_FMT_YUV420P12 },
> +    [DAV1D_PIXEL_LAYOUT_I422] = { AV_PIX_FMT_YUV422P,
> AV_PIX_FMT_YUV422P10, AV_PIX_FMT_YUV422P12 },
> +    [DAV1D_PIXEL_LAYOUT_I444] = { AV_PIX_FMT_YUV444P,
> AV_PIX_FMT_YUV444P10, AV_PIX_FMT_YUV444P12 },
> +};
> +
>  static void libdav1d_log_callback(void *opaque, const char *fmt, va_list
> vl)
>  {
>      AVCodecContext *c = opaque;
> @@ -44,6 +54,57 @@ static void libdav1d_log_callback(void *opaque, const
> char *fmt, va_list vl)
>      av_vlog(c, AV_LOG_ERROR, fmt, vl);
>  }
>
> +static int libdav1d_picture_allocator(Dav1dPicture *p, void *cookie) {
> +    Libdav1dContext *dav1d = cookie;
> +    enum AVPixelFormat format = pix_fmt[p->p.layout][p->seq_hdr->hbd];
> +    int ret, linesize[4], h = FFALIGN(p->p.h, 128);
> +    uint8_t *aligned_ptr, *data[4];
> +    AVBufferRef *buf;
> +
> +    ret = av_image_fill_arrays(data, linesize, NULL, format,
> FFALIGN(p->p.w, 128),
> +                               h, DAV1D_PICTURE_ALIGNMENT);
> +    if (ret < 0)
> +        return ret;
> +
> +    if (ret != dav1d->pool_size) {
> +        av_buffer_pool_uninit(&dav1d->pool);
> +        // Use twice the amount of required padding bytes for aligned_ptr
> below.
> +        dav1d->pool = av_buffer_pool_init(ret + DAV1D_PICTURE_ALIGNMENT *
> 2, NULL);
> +        if (!dav1d->pool)
> +            return -ENOMEM;
>

AVERROR(ENOMEM) ?

+        dav1d->pool_size = ret;
> +    }
> +    buf = av_buffer_pool_get(dav1d->pool);
> +    if (!buf)
> +        return -ENOMEM;
> +
> +    // libdav1d requires DAV1D_PICTURE_ALIGNMENT aligned buffers, which
> av_malloc()
> +    // doesn't guarantee for example when AVX is disabled at configure
> time.
> +    // Use the extra DAV1D_PICTURE_ALIGNMENT padding bytes in the buffer
> to align it
> +    // if required.
> +    aligned_ptr = (uint8_t *)FFALIGN((uintptr_t)buf->data,
> DAV1D_PICTURE_ALIGNMENT);
> +    ret = av_image_fill_pointers(data, format, h, aligned_ptr, linesize);
> +    if (ret < 0) {
> +        av_buffer_unref(&buf);
> +        return ret;
> +    }
> +
> +    p->data[0] = data[0];
> +    p->data[1] = data[1];
> +    p->data[2] = data[2];
> +    p->stride[0] = linesize[0];
> +    p->stride[1] = linesize[1];
> +    p->allocator_data = buf;
> +
> +    return 0;
> +}
> +
> +static void libdav1d_picture_release(Dav1dPicture *p, void *cookie) {
> +    AVBufferRef *buf = p->allocator_data;
> +
> +    av_buffer_unref(&buf);
> +}
>

nit: keep { on a new line for functions

-- 
Vittorio