[MPlayer-users] invalid VBR header. help, please
mc5686 at mclink.it
Sun Mar 13 13:12:20 CET 2005
I'm quite new to mencoder and I managed to make my first full-size
capture from tv.
This is the script I use to capture:
if [ -n "$2" ]
v4lctl setstation $2
amixer set Line 90% mute cap
mencoder tv:// \
-tv driver=v4l2:device=/dev/video0:width=768:height=576:alsa \
-ovc lavc -lavcopts
-oac mp3lame -lameopts abr:br=128 \
-vf crop=720:544:24:16,denoise3d,pp=lb \
-sws 6 -of avi -o $fn -endpos $1
amixer set Line 0% mute nocap
Quality is great (filesize is huge, but that was expected :) ), but I
have a few, not really blocking questions already:
How can I record directly from bt878 audio?
someone suggested using the btaudio kernel module, but that does not
look right, since that's an oss module, while I use (to be precise:
"debian sarge uses") alsa and I know the bt87x module is loaded. I can
also set for recording using "alsamixer -c1", but I have been unable to
divine what to pass to the "-tv ...:alsa:device=" parameter. The fine
manual says to look at the "-ao alsa" option, but I found that slightly
cryptic :-(. If it is of any use: my /proc/asound/devices contains:
0: [0- 0]: ctl
20: [0- 4]: digital audio playback
27: [0- 3]: digital audio capture
26: [0- 2]: digital audio capture
25: [0- 1]: digital audio capture
16: [0- 0]: digital audio playback
24: [0- 0]: digital audio capture
33: : timer
32: [1- 0]: ctl
57: [1- 1]: digital audio capture
56: [1- 0]: digital audio capture
Where is the format of the .mplayer/config file detailed? I tried to use
it to hold some static info (norm, channels, ...) but it complains, so I
must have done something wrong and so I resorted using "v4lctl
REAL PROBLEM STARTS HERE
I tried to remove the embedded commercials using avidemux.
So far so good.
I followed instructions (recompute vbr and enable "smart copy") and I
ended up with no errors and a file with the right video, but a huge
(>>10s!!) audio/video desynchronization.
I then opened the same (original) .avi with virtualDub and it
VBR audio stream detected.
VirtualDub has detected an improper VBR audio encoding in the source AVI
file and will rewrite the audio header with standard CBR values during
processing for better compatibility. This may introduce up to 12848 ms
of skew from the video source. If this is unacceptable, decompress the
*entire* audio stream to an uncompressed WAV file and recompress with a
consant bitrate encoder. (bitrate: 130.4 +- 14.6 kbps)
End results (after commercial removal) are almost as bad as avidemux ones.
What should I do?
I understand I have better to leave VBR alone when encoding (shouldn't
the manual warn against using VBR?), but how can I salvage this recording?
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