Frequently
asked questions:
- No frames transcoded with
libdv-0.9. What happened?
I suspect you have hit the libdv-0.9 MMX run-time detection bug.
Please install libdv-0.9.5 or newer or downgrade to libdv-0.8. If you have avifile + DV codecs installed, you can also use
"-x af6".
- CSS keys were printed but ripping
stops immedatialy. Quoting Joern Reder:
Some users had problems with ripping DVDs since they
upgraded from transcode 0.5.3 to transcode 0.6.0.
One symptom was
that CSS keys were printed but ripping stops immedatialy after this. I
couldn't help with this issue, because I couldn't reproduce it on my
system, but now we know the solution (after a success report from Matt
Hutchinson): mixing transcode versions in different installation
directories (e.g. /usr and /usr/local) mostly doesn't work. transcode
dynamically loads modules and this easily fails, if several versions
are mixed on the system.
So delete transcode 0.5.3 before upgrading or make sure that the old
binaries are overwritten. Check for binaries named tc*, avi* and
transcode in /usr/bin (or /usr/local/bin - attention: not all binaries
called this way need to belong to transcode, so check twice) and also
for a library directory called transcode in /usr/lib (or /usr/local/lib).
- I get only weired colors, faces are blue?
Use the "-k" option to swap blue and red color
components of the internal RGB representation.
- Encoding to DivX/XviD picture color is somehow screwed by
colored shadows. What's wrong?
The video frame size (width and height) on export
must be a multiple of 16 due to internal encoder
restrictions. Also do not use cropping with odd parameters,
like "-j 45" in conjunction with internal Y'CbCr (YV12/I420)
color space representation
- I have strange colors artifact using recent divx codec
(divx4, ffmpeg) for playing my encoded movie. They are
not present using older codecs (divx3, opendivx).
Your movie dimensions are probably incorrect, try re-encoding it with 16
multiple height and width.
- I try to encode a DVD PCM audio stream, but the
resulting stream sounds like white noise?
In most cases, DVD PCM audio tracks require swapping
of audio bytes with option "-d".
- Do I need the avifile library to read and write AVI-files?
No. transcode comes with native AVI-file support. AVI-files
with multiple audio tracks are also supported by transcode.
- I have avifile v0.6 installed but transcode gives me errors
compiling the related modules. What can I do?
You can either disable avifile support by using the configure option
"--with-avifile-mods=no" or use a newer working official 0.6
snapshot. transcode is known to compile and work with CVS
snapshot of 2001-12-07.
- Will transcode work with latest avifile v0.7?
Maybe. Untested.
- I have liba52 v0.7.2 installed but transcode gives me errors
compiling the related modules. What can I do?
Please upgrade to liba52 v0.7.3 and make sure all static and
dynamic libs of the old package are removed. Older versions of
transcode (<0.6.0pre3) however require liba52 v0.7.2 but
do not work properly. Upgrading is recommended.
- SuSE Linux 7.3 & 8.0 - mp2enc/mpeg2enc not found.
Obwohl das mjpegtools-Paket installiert ist, findet transcode die
Befehle mp2enc und mpeg2enc nicht. SuSE hat bei der Erstellung des
RPM-Paketes diese beiden Programme "vergessen". Um diesen Fehler zu
beheben, einfach das vorhandene Paket deinstallieren (rpm -e paket) und
das Originalpaket (http://download.sourceforge.net/mjpeg/) installieren
(rpm -i paket). Wichtig ist, dass das vorhandene Paket deinstalliert
wird, da in diesem Fall das neuere Paket als aelter erkannt und nicht
installiert wird, obwohl es eindeutig das neuere ist.
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Audio and video synchronization issues: |
- My DivX/XviD movie encoded from a NTSC DVD is out of sync. What is wrong?
This is a very complex issue. I will devote this a separate
entry somewhere else.
- Audio-Video out of sync after merging encoded DV or VOB
clips?
There is a fundamental problem when merging files with MP3 sound, that
have been transcoded individually. As far as I know, it needs a certain
amount of raw PCM data to make a MP3 encoded frame. At the end of the
encoding process, this condition is almost never fullfilled. Therefore,
some audio data are simply not encoded, or, using option -O, PCM data
are padded to make a final full MP3 frame. In the former case,
sound is too short in time, whereas in the latter, the audio played
by a player exceeds the video playtime. This may be only a few milliseconds
but add up when merging the clips.
- What is the advantage using option "-t" in contrast to
DVD chapter mode "-U"?
With option "-t", the MP3 encoder is not switched off. Buffered audio data
never get lost. After merging, audio and video are OK (in theory).
This is also the reason, why the cluster mode must use this approach encoding
the audio in a separate step, unless you want to use raw
PCM audio data. The chapter mode, however, splits
logical movie units, which may be useful for other reasons.
- avisplit breaks AV synchronization. What happened?
aviplit is only able to correctly split transcode generates
AVI-files, i.e., interleaved files with video/audio frames paired.
- Why is transcode so slow? It sucks.
Most processor time is spent in the codec on the
export side. Video frame processing sometimes is slow
depending
on the complexity of the operation. However, the most
significant
speedup is achieved by switching to internal Y'CbCr (YV12/I420)
representation
by using "-V". Most modules support this color space
representation which speeds up everything from decoding to
processing and re-encoding. On the down-side, color
information gets lost but is barely notable. Decide for
yourself
if you need high-quality results or a quick backup copy.
- I have a couple of DV AVI-file clips I want to transcode as
a single movie without merging. How does it work?
The "directory mode" with option "-i" also works for DV AVI-files (hopefully).
Try to put all clips into a directory and use the directory name
to let transcode extract and merge the raw DV stream for further processing.
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