baseparse: Add missing gst_buffer_make_writable

When the subclass attempts to finish without an explicit `out_buffer`,
we take a buffer from our adapter. We need to make this buffer writable
before copying the metadata.

This led to data races such as in the following pipeline, which randomly
messed up the buffer PTS:

    gst-launch-1.0 -e audiotestsrc timestamp-offset=5555 num-buffers=100 \
      ! opusenc ! tee name=t ! queue ! opusparse ! fakesink silent=0 \
      t. ! queue ! opusparse ! fakesink silent=0 -v | grep '0000, dur'

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5720>

diff --git a/subprojects/gstreamer/libs/gst/base/gstbaseparse.c b/subprojects/gstreamer/libs/gst/base/gstbaseparse.c
index 4e7c46e4415d994c2043c30bf49ce2dbe7b176d2..8f3e1523317176af8694b6ee00a687593723518a 100644 (file)
--- a/subprojects/gstreamer/libs/gst/base/gstbaseparse.c
+++ b/subprojects/gstreamer/libs/gst/base/gstbaseparse.c
@@ -2728,6 +2728,7 @@ gst_base_parse_finish_frame (GstBaseParse * parse, GstBaseParseFrame * frame,
     GstBuffer *src, *dest;
 
     frame->out_buffer = gst_adapter_take_buffer (parse->priv->adapter, size);
+    frame->out_buffer = gst_buffer_make_writable (frame->out_buffer);
     dest = frame->out_buffer;
     src = frame->buffer;
     GST_BUFFER_PTS (dest) = GST_BUFFER_PTS (src);