Created attachment 45472 [details]
dvdsubdec files

Created attachment 45473 [details] [review]
configure.ac changes

Basically, I've set it up so the element walks the commands in each subtitle
packet as time advances
time is advanced either by a new subtitle packet arriving, or a filler event
each frame is emitted with a timestamp and no duration, including blank frames
for turning each subtitle off.

dvdsubdec should connect to a videomixer that understands this method of
describing the stream, which doesn't exist yet I don't think

Created attachment 45488 [details]
updated version with clipping bug fixed

Created attachment 45514 [details]
version that generates definite durations

This version generates buffers with a duration, reemitting the 'current' buffer
with a new timestamp as it receives new filler events.

The element looks good now. Sending the same buffer is not ideal, but can be
worked around in muxers and is better than nothing.

I'd recommend to not apply it yet. Reason is that we cannot actually use it yet,
which will lead to users commenting "where are the DVD subtitles I saw in the
release notes?". I'd recommend merging this together with the imagemixer
element, which I'd like to use for subpicture merging.

Minor comment: I don't like the way in which you negotiate an output format, at
the very least, the missing of a fixation function here will cause major issues.

(of course, this comment was done before I noticed the fixed pad template... n/m.

Created attachment 47259 [details] [review]
update

Your version sets the alpha value using only 4 bits (0..15), which is the DVD
alpha depth. We need to <<4 it to make it useful in AYUV, so it displays fine
when  overlayed over DVD frames. This patch fixes that.

Created attachment 47605 [details] [review]
another update

* set rank so playbin recognizes it for autoplugging (see #306555 for the
playbin patch).

Created attachment 47985 [details] [review]
update

* swap U/V, seems to fix some color issues.

applied.