Multiple MPEG
program stream chunks (VOB) ---> DivX
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Here is a 3 step guide to rip a DVD and convert the multiple VOB
chunks, or only a single file, using transcode:
- We rip the DVD and put all VOB chunks, that make up the
actual movie into a subdirectory, denoted
here as
"my_movie/". For an encrypted DVD, we will need
libdvdcss under linux to do this, but this may
not be legal.
If you do not need DVD navigation or multiple angle
features,
the ripping is done by:
tccat -i /dev/dvd -T 1,-1 | split -b 1024m - my_movie/movie-
I assume, "/dev/dvd" is a link to the DVD
device and the main title is 1.
The DVD does not have to be mounted, just
put it in the drive. After some time,
we chunks named: movie-aa, movie-ab, ...,
which are, but the last, exactly 1GB.
The following is also valid, if we have used other
programs to copy the DVD title VOBs onto the
harddisk.
It's a good idea, to let tcprobe take a look
at the files you want to encode. This is done
by typing:
tcprobe -i my_movie/
assuming that "my_movie/" is a directory in your
present work directory.
The output may look like
[tcprobe] MPEG program stream
[tcprobe] summary for my_movie/, (*) = not default, 0 = not detected
import frame size: -g 720x480 [720x576] (*)
aspect ratio: 16:9 (*)
frame rate: -f 23.976 [25.000] frc=1 (*)
audio track: -a 0 [0] -e 48000,16,2 [48000,16,2] -n 0x2000 [0x2000]
detected (6) subtitle(s)
As you can see, the auto-probing feature has
detected a NTSC program stream with a single AC3
audio track. In the following, we only need to take
care of the aspect ratio 16:9, but that has already been
explained in the previous section.
- Now we can invoke transcode with the directory
mode, that internally concatenates all VOB
chunks. If
you need more bitrate or audio renormalization
information,
check the DVD section. The default is for MP3 audio
encoding:
AC3->MP3
transcode |
-i my_movie/ -V |
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-j 0,8 -B 3,1 |
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-t 10000,movie -y divx4 |
To enable AC3 pass-through,
use "-A" and use "-N 0x2000"
to set the proper codec
in the AVI file and the player. The default audio
track
is 0, which is in most cases the original language. If you
want to have AC3 sound in your AVI-file, use:
AC3->AC3
transcode |
-i my_movie/ -V -A |
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-j 0,8 -B 3,1 |
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-t 10000,movie -y divx4 -N 0x2000 |
If you own a DVD with uncompressed PCM audio, e.g., audio track 1,
and
want to keep the quality, i.e., pass-through the sound, use:
PCM->PCM
transcode |
-i my_movie/ -V -a 1 |
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-j 0,8 -B 3,1 |
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-t 10000,movie -y divx4 -N 0x1 |
If your DVD has MPEG audio, it's usually MP2 format. This is
automatically
detected and recompression to MP3 audio is performed with the
default settings. However, if you need to resample your sound, here
is an example, using audio track 2:
MP2->MP3
transcode |
-i my_movie/ -V -a 2 |
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-j 0,8 -B 3,1 -E 44100 |
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-t 10000,movie -y divx4 |
The "-t" option
splits the output into separate files labeled movie000.avi,
movie001.avi,..., with exactly
10000 frames per file.
On my CII 533@800 MHz, I get around 11 fps for the
encoding, using the "-V" mode, which saves alot of
bandwidth.
This will take some hours, but since we work with linux,
we don't need to care, just wait.
-
If you want to play around with other codecs, use
the avifile "-y af6" export module and the option
"-F". To learn about available codecs, just use "-F foo"
and a list with tons of codecs is displayed.
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If you have to interrupt your session
for some reason, you can always restart with the
help of the "-c" option. You only need to count the
valid files, i.e., with 10000 frames,
already encoded to find out the first
parameter for this option. Drop the last AVI file
for it may be broken, but this is not the case if
you use ^C. Also use some other
basename for the "-t", like "-t 10000,movie1" to make
sure, not to overwrite your old files. Ok, the
braindead seeking implementation takes some time, but this is
rarely used anyway.
- Take a look at the DVD section to learn how to avimerge
the AVI-files. After merging,
try to play the big files with
mplayer
and seek around. The audio/video synchronization
should be acceptable. If everything seems fine, go ahead
and burn your CDs. Note, that AC3 AVI files tend to
be up to 25% larger compared to MP3 audio, which is the
default for transcode.
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