On 2/21/2025 8:44 AM, Andreas Rheinhardt wrote:
James Almer:Signed-off-by: James Almer <jamr...@gmail.com> --- libavutil/frame.h | 19 +++++++++++++++++++ libavutil/side_data.c | 25 +++++++++++++++++++++++++ 2 files changed, 44 insertions(+)diff --git a/libavutil/frame.h b/libavutil/frame.h index 49260ae2dd..a707b35087 100644 --- a/libavutil/frame.h +++ b/libavutil/frame.h @@ -1211,6 +1211,25 @@ void av_frame_side_data_remove(AVFrameSideData ***sd, int *nb_sd, void av_frame_side_data_remove_by_props(AVFrameSideData ***sd, int *nb_sd, int props);+/**+ * Check whether the data described by a given AVFrameSideData can be + * written to. + * + * @return 1 if the caller may write to the data, 0 otherwise. + */ +int av_frame_side_data_is_writable(const AVFrameSideData *sd); + +/** + * Create a writable reference for the data described by a given + * AVFrameSideData, avoiding data copy if possible. + * + * @param sd Side data whose data should be made writable. + * + * @return 0 on success, a negative AVERROR on failure. On failure, the + * side data is unchanged. + */ +int av_frame_side_data_make_writable(AVFrameSideData *sd);I don't see the point of either of them: The former is just a wrapper around av_buffer_is_writable() and the latter is basically the same as av_buffer_make_writable() (and could actually use it). If this is designed with using something else but flat buffers in the future in mind, then av_frame_side_data_make_writable() is misdesigned, because making a non-flat object writable is ambiguous: It is not clear whether making something writable is meant in a shallow or a deep sense which may become an issue if future side-data contains references of its own.
In the previous iteration of this set, where i added RefCount as backing for the side data, av_frame_side_data_make_writable() included per type callbacks in the descriptors that would take care of any kind of refcounted buffer or object within the side data.
I can skip this patch in any case, since you were against adding the RefCount backing implementation right now, its usefulness is limited.
+ /** * @} */ diff --git a/libavutil/side_data.c b/libavutil/side_data.c index 8c57fd838a..beb8ea3212 100644 --- a/libavutil/side_data.c +++ b/libavutil/side_data.c @@ -315,3 +315,28 @@ const AVFrameSideData *av_frame_side_data_get_c(const AVFrameSideData * const *s } return NULL; } + +int av_frame_side_data_is_writable(const AVFrameSideData *sd) +{ + return !!av_buffer_is_writable(sd->buf);av_buffer_is_writable() is documented to only return 0 or 1, so the binarization is unnecessary.+} + +int av_frame_side_data_make_writable(AVFrameSideData *sd) +{ + AVBufferRef *buf = NULL; + + if (av_buffer_is_writable(sd->buf)) + return 0; + + buf = av_buffer_alloc(sd->size); + if (!buf) + return AVERROR(ENOMEM); + + if (sd->size) + memcpy(buf->data, sd->data, sd->size); + av_buffer_unref(&sd->buf); + sd->buf = buf; + sd->data = buf->data; + + return 0; +}_______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
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