[FFmpeg-devel] [PATCH 2/2] avutil: make AVFrameSideData buffers ref-counted.

[wm4]

On Mon, 23 Mar 2015 11:11:19 -0400
"Ronald S. Bultje" <rsbultje at gmail.com> wrote:

> ---
>  libavutil/frame.c | 53 ++++++++++++++++++++++++++++++++++++++---------------
>  libavutil/frame.h |  1 +
>  2 files changed, 39 insertions(+), 15 deletions(-)
> 
> diff --git a/libavutil/frame.c b/libavutil/frame.c
> index 85f5637..4596927 100644
> --- a/libavutil/frame.c
> +++ b/libavutil/frame.c
> @@ -115,7 +115,7 @@ static void free_side_data(AVFrameSideData **ptr_sd)
>  {
>      AVFrameSideData *sd = *ptr_sd;
>  
> -    av_freep(&sd->data);
> +    av_buffer_unref(&sd->buf);
>      av_dict_free(&sd->metadata);
>      av_freep(ptr_sd);
>  }
> @@ -275,7 +275,7 @@ int av_frame_get_buffer(AVFrame *frame, int align)
>      return AVERROR(EINVAL);
>  }
>  
> -int av_frame_copy_props(AVFrame *dst, const AVFrame *src)
> +static int frame_copy_props(AVFrame *dst, const AVFrame *src, int force_copy)
>  {
>      int i;
>  
> @@ -320,13 +320,28 @@ int av_frame_copy_props(AVFrame *dst, const AVFrame *src)
>          if (   sd_src->type == AV_FRAME_DATA_PANSCAN
>              && (src->width != dst->width || src->height != dst->height))
>              continue;
> -        sd_dst = av_frame_new_side_data(dst, sd_src->type,
> -                                        sd_src->size);
> -        if (!sd_dst) {
> -            wipe_side_data(dst);
> -            return AVERROR(ENOMEM);
> +        if (force_copy) {
> +            sd_dst = av_frame_new_side_data(dst, sd_src->type,
> +                                            sd_src->size);
> +            if (!sd_dst) {
> +                wipe_side_data(dst);
> +                return AVERROR(ENOMEM);
> +            }
> +            memcpy(sd_dst->data, sd_src->data, sd_src->size);
> +        } else {
> +            sd_dst = av_frame_new_side_data(dst, sd_src->type, 0);
> +            if (!sd_dst) {
> +                wipe_side_data(dst);
> +                return AVERROR(ENOMEM);
> +            }
> +            sd_dst->buf = av_buffer_ref(sd_src->buf);
> +            if (!sd_dst->buf) {
> +                wipe_side_data(dst);
> +                return AVERROR(ENOMEM);
> +            }
> +            sd_dst->data = sd_dst->buf->data;
> +            sd_dst->size = sd_dst->buf->size;
>          }
> -        memcpy(sd_dst->data, sd_src->data, sd_src->size);
>          av_dict_copy(&sd_dst->metadata, sd_src->metadata, 0);
>      }
>  
> @@ -356,7 +371,7 @@ int av_frame_ref(AVFrame *dst, const AVFrame *src)
>      dst->channel_layout = src->channel_layout;
>      dst->nb_samples     = src->nb_samples;
>  
> -    ret = av_frame_copy_props(dst, src);
> +    ret = frame_copy_props(dst, src, 0);
>      if (ret < 0)
>          return ret;
>  
> @@ -530,6 +545,11 @@ int av_frame_make_writable(AVFrame *frame)
>      return 0;
>  }
>  
> +int av_frame_copy_props(AVFrame *dst, const AVFrame *src)
> +{
> +    return frame_copy_props(dst, src, 1);
> +}
> +
>  AVBufferRef *av_frame_get_plane_buffer(AVFrame *frame, int plane)
>  {
>      uint8_t *data;
> @@ -580,13 +600,16 @@ AVFrameSideData *av_frame_new_side_data(AVFrame *frame,
>      if (!ret)
>          return NULL;
>  
> -    ret->data = av_malloc(size);
> -    if (!ret->data) {
> -        av_freep(&ret);
> -        return NULL;
> -    }
> +    if (size > 0) {
> +        ret->buf = av_buffer_alloc(size);
> +        if (!ret->buf) {
> +            av_freep(&ret);
> +            return NULL;
> +        }
>  
> -    ret->size = size;
> +        ret->data = ret->buf->data;
> +        ret->size = size;
> +    }
>      ret->type = type;
>  
>      frame->side_data[frame->nb_side_data++] = ret;
> diff --git a/libavutil/frame.h b/libavutil/frame.h
> index 6b9ac6a..e65ad79 100644
> --- a/libavutil/frame.h
> +++ b/libavutil/frame.h
> @@ -129,6 +129,7 @@ typedef struct AVFrameSideData {
>      uint8_t *data;
>      int      size;
>      AVDictionary *metadata;
> +    AVBufferRef *buf;
>  } AVFrameSideData;
>  
>  /**

What if someone wants to do write-accesses to the side-data? I don't
think this patch handles this case.  av_frame_make_writable() should be
extended.