Bad transcoding performance under Vista SP1

[akramh]

Hi guys,

Am trying to transcode an MPEG4 RTSP stream to WMV using player 0.9.8a 'Grishenko'. I basically need to create WMV files that Windows media player can read without extra codecs.

I have used the command line: :sout=#transcode{vcodec=WMV2,vb=768,scale=1}:duplicate{dst=display,dst=std{access=file,mux=asf,dst=C:\Users\Akramh\Desktop\blah.wmv}}
And the file is recorded: however, the stream which plays back beautifully normally (i.e. when I do not transcode) has a grey overlay, numerous artefacts and what appear to be dropped frames. I can open the file in WMP and it plays back -- but the video quality is destroyed as it was in the display out.

Using this command: :sout=#transcode{vcodec=WMV2,vb=768,scale=1}:duplicate{dst=std{access=file,mux=asf,dst=C:\Users\Akramh\Desktop\blah.wmv}}
I get a file that I can open in WMP -- however it appears the header of the file has not been written correctly; I record for 10 seconds and 'stop' manually in the VLC UI -- but the file believes it is 26 minutes long -- and does not playback in WMP properly. I can playback the file in VLC -- where the quality is good, however VLC reports the same file length as WMP (though VLC at least plays it).

Ideas for how I can get this to work? Transcoding with a duplicate sout to display would be best, but if I cannot, then straight to file would be fine too.

Computer is a quad-core intel with 4gb of RAM, surely I have enough grunt to perform this simple transcoding task!!

For reference, I am not saving audio -- as it is not being transmitted in the RTSP stream.

[VLC_help]

has a grey overlay, numerous artefacts and what appear to be dropped frames

known issue http://trac.videolan.org/vlc/ticket/2453

[akramh]

Update:
This would appear to be an introduced issue. Issuing the commands above under 0.9.2 allows me to record WMV without any artefacts or dropped frames -- so I have reverted to that version. I wonder what has changed? 0.9.6 has the bug also, it seems.

EDIT: 0.9.2 only worked once; now retrying the command causes the same sort of image corruption

[VLC_help]

Compression artifacts might be libavcodec related, so increasing bitrate might help. But I don't know where the grey overlay comes.