The existing code attempts to clear the frame by painting in OVER mode with transparent black - which is, of course, a no-op. As a result if you have many input frames (e.g. you're using a sequence of svg files), you'll start to see new frames drawn over old frames as memory gets re-used.
Fix that by clearing the frame using the SOURCE blend mode, which will replace whatever is in the buffer with transparent black. Referencing the cairo FAQ, https://www.cairographics.org/FAQ/#clear_a_surface --- libavcodec/librsvgdec.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) It would probably be nice to get this into 3.4 branch as well? diff --git a/libavcodec/librsvgdec.c b/libavcodec/librsvgdec.c index e57070f8e4..e16cb6247d 100644 --- a/libavcodec/librsvgdec.c +++ b/libavcodec/librsvgdec.c @@ -82,8 +82,11 @@ static int librsvg_decode_frame(AVCodecContext *avctx, void *data, int *got_fram crender = cairo_create(image); - cairo_set_source_rgba(crender, 0.0, 0.0, 0.0, 1.0f); - cairo_paint_with_alpha(crender, 0.0f); + cairo_save(crender); + cairo_set_source_rgba(crender, 0.0, 0.0, 0.0, 0.0f); + cairo_set_operator(crender, CAIRO_OPERATOR_SOURCE); + cairo_paint(crender); + cairo_restore(crender); cairo_scale(crender, dimensions.width / (double)unscaled_dimensions.width, dimensions.height / (double)unscaled_dimensions.height); _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel