[gstreamer-bugs] [Bug 593647] ffdec_flashsv doesn't work

[GStreamer (bugzilla.gnome.org)]

http://bugzilla.gnome.org/show_bug.cgi?id=593647


Jarkko Palviainen <jarkko.palviainen> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jarkko.palviainen at sesca.com


--- Comment #1 from Jarkko Palviainen <jarkko.palviainen at sesca.com> 2009-09-07 06:42:12 UTC ---
Confirming. Mplayer even works when using the same ffmpeg/avcodec libraries as
gst-ffmpeg in git.

Here's a snippet from libavcodec/flashsv.c for the bitstream description of
Flash Screen Video decoder:

"Directly after the header are the compressed blocks. The blocks
have their compressed size represented with 16bits in the beginnig.
If the size = 0 then the block is unchanged from the previous frame.
All blocks are decompressed until the buffer is consumed."

This points out that previous frame should be preserved (and the codec
implementation is not doing that for us). On the other hand, the gst plugin
seems to only allocate an empty buffer for the next frame. The example video is
a desktop recording, which contains a lot of unchanged regions, thus major
parts of the frames show as black. 

I already wrote a quick hack to fix this, but it needs some checking to avoid
breaking stuff elsewhere, since the gst plugin handles all codecs in one place.

-- 
Configure bugmail: http://bugzilla.gnome.org/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are the QA contact for the bug.
You are the assignee for the bug.