[FFmpeg-devel] [PATCH] avutil/frame: add av_frame_replace

[Andreas Rheinhardt]

James Almer:
> Signed-off-by: James Almer <jamrial at gmail.com>
> ---
> Now taking into account the new channel layout API fields, supporting non
> refcouted src, plus changing the documentation to state that the dst frame
> properties will be replaced by those from src even if the data described
> by both frames is the same.
> 

Apparently, you didn't get my point last time: What happens if dst and
src coincide did not mean "what happpens if the data both frames refer
to already coincides"; it meant "what happens if src == dst?" (so that
there is only one AVFrame involved). You either disallow this altogether
or you support it. This patch (and the last one) does neither.

> Still missing APIChanges entry and version bump.
> 
>  libavutil/frame.c | 144 ++++++++++++++++++++++++++++++++++++++++++++++
>  libavutil/frame.h |  17 ++++++
>  2 files changed, 161 insertions(+)
> 
> diff --git a/libavutil/frame.c b/libavutil/frame.c
> index 4c16488c66..2a4a2c27ad 100644
> --- a/libavutil/frame.c
> +++ b/libavutil/frame.c
> @@ -461,6 +461,150 @@ fail:
>      return ret;
>  }
>  
> +int av_frame_replace(AVFrame *dst, const AVFrame *src)
> +{
> +    int i, ret = 0;

Why don't you use "for (int i = 0;" loop variables?

> +
> +    dst->format         = src->format;
> +    dst->width          = src->width;
> +    dst->height         = src->height;
> +    dst->nb_samples     = src->nb_samples;
> +#if FF_API_OLD_CHANNEL_LAYOUT
> +FF_DISABLE_DEPRECATION_WARNINGS
> +    dst->channels       = src->channels;
> +    dst->channel_layout = src->channel_layout;
> +    if (!av_channel_layout_check(&src->ch_layout)) {
> +        av_channel_layout_uninit(&dst->ch_layout);
> +        if (src->channel_layout)
> +            av_channel_layout_from_mask(&dst->ch_layout, src->channel_layout);
> +        else {
> +            dst->ch_layout.nb_channels = src->channels;
> +            dst->ch_layout.order       = AV_CHANNEL_ORDER_UNSPEC;
> +        }
> +    } else {
> +#endif
> +    ret = av_channel_layout_copy(&dst->ch_layout, &src->ch_layout);
> +    if (ret < 0)
> +        goto fail;
> +#if FF_API_OLD_CHANNEL_LAYOUT
> +    }
> +FF_ENABLE_DEPRECATION_WARNINGS
> +#endif
> +
> +    wipe_side_data(dst);
> +    av_dict_free(&dst->metadata);
> +    ret = frame_copy_props(dst, src, 0);
> +    if (ret < 0)
> +        goto fail;
> +
> +    /* duplicate the frame data if it's not refcounted */
> +    if (!src->buf[0]) {
> +        for (i = 0; i < FF_ARRAY_ELEMS(dst->buf); i++)
> +            av_buffer_unref(&dst->buf[i]);
> +        for (i = 0; i < dst->nb_extended_buf; i++)
> +            av_buffer_unref(&dst->extended_buf[i]);
> +        av_freep(&dst->extended_buf);
> +
> +        memset(dst->data, 0, sizeof(dst->data));
> +        if (dst->extended_data != dst->data)
> +            av_freep(&dst->extended_data);
> +
> +        ret = av_frame_get_buffer(dst, 0);
> +        if (ret < 0)
> +            goto fail;
> +
> +        ret = av_frame_copy(dst, src);
> +        if (ret < 0)
> +            goto fail;
> +
> +        ret = av_buffer_replace(&dst->hw_frames_ctx, src->hw_frames_ctx);
> +        if (ret < 0)
> +            goto fail;
> +
> +        return 0;
> +    }
> +
> +    /* replace the buffers */
> +    for (i = 0; i < FF_ARRAY_ELEMS(src->buf); i++) {
> +        ret = av_buffer_replace(&dst->buf[i], src->buf[i]);
> +        if (ret < 0)
> +            goto fail;
> +    }
> +
> +    if (src->extended_buf) {
> +        if (dst->nb_extended_buf != src->nb_extended_buf) {
> +            int nb_extended_buf = FFMIN(dst->nb_extended_buf, src->nb_extended_buf);
> +            void *tmp;
> +
> +            for (i = nb_extended_buf; i < dst->nb_extended_buf; i++)
> +                av_buffer_unref(&dst->extended_buf[i]);
> +
> +            tmp = av_realloc_array(dst->extended_buf, sizeof(*dst->extended_buf),
> +                                   src->nb_extended_buf);
> +            if (!tmp) {
> +                ret = AVERROR(ENOMEM);
> +                goto fail;
> +            }
> +            dst->extended_buf = tmp;
> +            dst->nb_extended_buf = src->nb_extended_buf;
> +
> +            memset(&dst->extended_buf[nb_extended_buf], 0,
> +                   (src->nb_extended_buf - nb_extended_buf) * sizeof(*dst->extended_buf));
> +        }
> +
> +        for (i = 0; i < src->nb_extended_buf; i++) {
> +            ret = av_buffer_replace(&dst->extended_buf[i], src->extended_buf[i]);
> +            if (ret < 0)
> +                goto fail;
> +        }
> +    } else if (dst->extended_buf) {
> +        for (i = 0; i < dst->nb_extended_buf; i++)
> +            av_buffer_unref(&dst->extended_buf[i]);
> +        av_freep(&dst->extended_buf);
> +    }
> +
> +    ret = av_buffer_replace(&dst->hw_frames_ctx, src->hw_frames_ctx);
> +    if (ret < 0)
> +        goto fail;
> +
> +    if (dst->extended_data != dst->data)
> +        av_freep(&dst->extended_data);
> +
> +    if (src->extended_data != src->data) {
> +        int ch = src->ch_layout.nb_channels;
> +
> +#if FF_API_OLD_CHANNEL_LAYOUT
> +FF_DISABLE_DEPRECATION_WARNINGS
> +        if (!ch) {
> +            ch = src->channels;
> +            CHECK_CHANNELS_CONSISTENCY(src);
> +        }
> +FF_ENABLE_DEPRECATION_WARNINGS
> +#endif
> +        if (!ch) {
> +            ret = AVERROR(EINVAL);
> +            goto fail;
> +        }
> +
> +        dst->extended_data = av_malloc_array(sizeof(*dst->extended_data), ch);
> +        if (!dst->extended_data) {
> +            ret = AVERROR(ENOMEM);
> +            goto fail;
> +        }
> +        memcpy(dst->extended_data, src->extended_data, sizeof(*src->extended_data) * ch);
> +    } else
> +        dst->extended_data = dst->data;
> +
> +    memcpy(dst->data,     src->data,     sizeof(src->data));
> +    memcpy(dst->linesize, src->linesize, sizeof(src->linesize));
> +
> +    return 0;
> +
> +fail:
> +    av_frame_unref(dst);
> +    return ret;
> +}
> +
>  AVFrame *av_frame_clone(const AVFrame *src)
>  {
>      AVFrame *ret = av_frame_alloc();
> diff --git a/libavutil/frame.h b/libavutil/frame.h
> index 33fac2054c..a971b1655e 100644
> --- a/libavutil/frame.h
> +++ b/libavutil/frame.h
> @@ -752,6 +752,23 @@ void av_frame_free(AVFrame **frame);
>   */
>  int av_frame_ref(AVFrame *dst, const AVFrame *src);
>  
> +/**
> + * Ensure the destination frame refers to the same data described by the source
> + * frame by creating a new reference for each AVBufferRef from src if they
> + * differ from those in dst, or if src is not reference counted, by allocating
> + * new buffers and copying data.
> + *
> + * Frame properties on dst will be replaced by those from src.
> + *
> + * @param src The source frame. If there's data described in it, it must be
> + *            reference counted.

The text above says "if src is not reference counted, by allocating new
buffers and copying data".

> + * @param dst The destination frame.
> + *
> + * @return 0 on success, a negative AVERROR on error. On error, dst is
> + *         unreferenced.
> + */
> +int av_frame_replace(AVFrame *dst, const AVFrame *src);
> +
>  /**
>   * Create a new frame that references the same data as src.
>   *