Table of Contents
Mplayer and mencoder
Mplayer was also very useful in extracting audio (AC3) and video (MPEG2) from a badly encoded DVD, see Errori nella struttura di un DVD Video.
-dvd-device <path to device>
Specifica il device DVD, predefinito
/dev/dvd. Si può indicare anche una directory che contiene i file precedentemente copiati dal DVD (ad esempio con
dvdbackup o con
vobcopy). Di solito per copiare il contenuto di un DVD la via migliore è l'utilizzo dell'opzione
Selezione scheda ALSA per output audio
In questo esempio viene selezionata la seconda scheda audio (la prima ha il numero zero) per l'output:
mplayer -ao alsa:device=hw=1.0 file.avi
If you want to execute
mplayer as non-privileged user, set
/dev/rtc device to mode 0664. As far I know, this does not pose any security issuse. The usage of
/dev/rtc can help synchronizing audio/video. Mplayer needs the ability to use high resolution timers, run this command as root every time your machine boots:
echo 1024 > /proc/sys/dev/rtc/max-user-freq
You can achieve the same result adding to
/etc/sysctl.conf this line:
Check that you have the latest version of the file. With the Debian Marillat package you get it into
/usr/share/doc/mplayer-k6/examples/. The same apply for the
Converting audio file with mplayer
In this example we will convert a Microsoft ASF audio file into a more usable WAVE audio PCM:
mplayer sample.asf -vo null -ao pcm:file=sample.wav
How to extract subtitles from a DVD-Video into VobSub format
A better way to convert DVD-Video subtitles into VobSub format is to use transcode.
This is because mencoder seems to produce different image data into the
.sub file and slightly different timestamps into the index (
.idx) file depending on the used video codec (
-ovc option): strange enough, I got different outputs using copy and raw options. Transcode instead seems to be more deterministic.
We can use
mplayer to identify subtitle streams contained into the DVD, they are identified by an ID and a language:
mplayer -dvd-device $RIPDIR dvd://$TITLE -identify ... ID_SUBTITLE_ID=0 ID_SID_0_LANG=it ID_SUBTITLE_ID=1 ID_SID_1_LANG=en ID_SUBTITLE_ID=2 ID_SID_2_LANG=it ...
The following command will generate two files:
vobsubs-en.idx from the second subtitles stream (sid = 1).
mencoder -dvd-device $RIPDIR dvd://$TITLE \ -nosound -ovc copy -o /dev/null \ -ifo $RIPDIR/VIDEO_TS/VTS_01_0.IFO \ -sid 1 -vobsubout vobsubs-en
With vobsub2pgm you can convert VobSub subtitles into single .pgm images.
Ripping a DVD with mplayer
Sometimes trascoding a video DVD with
avidemux (my favourite transcoding program) does not give correct results. I transcode the VOB files directly from the DVD, but the resulting video gets the multi-angle scenes interlaced. I think that the problem aroses from
avidemux not being able to cope with DVD multi-angle scenes.
mplayer instead plays the video correctly, so I use
mplayer to extract a MPEG stream, and then I user
avidemux to transcode.
First of all, we can play a DVD track from an .iso image mounted with the loop option. In this example we play track #27, using audio track ID 130 and no subtitles:
mount -o loop,ro dvdimage.iso /media/cdrom mplayer dvd://27//media/cdrom -aid 130 -nosub
With this command we will dump track #27 to a raw compressed file, the file will contains all the audio tracks and subtitles:
mplayer dvd://27//media/cdrom -dumpstream -dumpfile dvd_track_27.vob
The dumped file can be played with
mplayer or opened (and transcoded in XviD/mp3) with