OGMMERGE(1) User Commands OGMMERGE(1)NAMEogmmerge - Merge multimedia streams into an OGG/OGM file
SYNOPSISogmmerge [global options] -o out [options] <file1> [[options] <file2>
...]
DESCRIPTION
This program takes the input from several media files and joins their
streams (all of them or just a selection) into an OGM. It was formerly
known as 'oggmerge' and is based on the 'oggmerge' CVS module from
Xiph's repository (<http://www.xiph.org/>). ⟨http://www.xiph.org/⟩
Global options:
-v, --verbose
Increase verbosity.
-q, --quiet
Suppress status output.
-o, --output out
Write to the file 'out'.
Options that can be used for each input file:
-a, --astreams <n,m,...>
Copy the n'th audio stream, NOT the stream with the serial no.
n. Default: copy all audio streams.
-d, --vstreams <n,m,...>
Copy the n'th video stream, NOT the stream with the serial no.
n. Default: copy all video streams.
-t, --tstreams <n,m,...>
Copy the n'th text stream, NOT the stream with the serial no. n.
Default: copy all text streams.
-A, --noaudio
Don't copy any audio stream from this file.
-D, --novideo
Don't copy any video stream from this file.
-T, --notext
Don't copy any text stream from this file.
-s, --sync <d[,o[/p]]>
Synchronize manually, delay the audio stream by d ms.
d > 0: Pad with silent samples.
d < 0: Remove samples from the beginning.
o/p: adjust the timestamps by o/p to fix linear drifts. p
defaults to 1000 if omitted. Both o and p can be floating point
numbers.
Defaults: no manual synch correction (which is the same as d = 0
and o/p = 1.0).
-r, --range <start-end>
Only process from start to end. Both values take the form
'HH:MM:SS.mmm' or 'SS.mmm', e.g. '00:01:00.500' or '60.500'. If
one of start or end is omitted then it defaults to 0 or to end
of the file respectively.
If you want to split a file into smaller ones I strongly suggest
you use ogmsplit(1) as it can do a much better job than using
the -r option.
-c, --comment 'A=B#C=D' or '@filename'
Set additional comment fields for the streams. Sensitive values
would be 'LANGUAGE=English' or 'TITLE=Ally McBeal'. If the
parameter starts with '@' then the comments will be read from a
file with the same name without the leading '@'. -c can be spec‐
ified multiple times per file. The comments will all be concate‐
nated.
-f, --fourcc <FourCC>
Forces the FourCC to the specified value. Works only for video
streams. Note that you cannot simply use a hex editor and change
the FourCC by hand as the OGG file format uses checksums which
would be wrong after such a change.
--omit-empty-packets
Normally, when a subtitle entry should be removed, an empty
packet is created and inserted with the appropriate timestamp.
With this option these empty packets are omitted completely.
--old-headers
Assume that the input file has been created with an older ver‐
sion of ogmmerge ( < 1.1). This may be needed if ogmmerge cannot
read such a file correctly.
--nav-seek <filename>
Use an external AVI index file as generated by aviindex from the
transcode package. Can be used if an AVI file has a broken
index.
Other options:
-l, --list-types
List supported input file types.
-h, --help
Show usage information.
-V, --version
Show version information.
USAGE
For each file the user can select which tracks ogmmerge should take.
They are all put into the file specified with '-o'. A list of known
(and supported) source formats can be obtained with the '-l' option.
EXAMPLES
Let's assume you have a file called MyMovie.avi and the audio track in
a separate file, e.g. MyMovie.wav. First you want to encode the audio
to OGG:
$ oggenc -q4 -oMyMovie.ogg MyMovie.wav
After a couple of minutes you can join video and audio:
$ ogmmerge-o MyMovie-with-sound.ogm MyMovie.avi MyMovie.ogg
If your AVI already contains an audio track then it will be copied
aswell (if ogmmerge supports the audio format). To avoid that simply do
$ ogmmerge-o MyMovie-with-sound.ogm -A MyMovie.avi MyMovie.ogg
After some minutes of consideration you rip another audio track, e.g.
the director's comments or another language to MyMovie-add-audio.wav.
Encode it again and join it up with the other file:
$ oggenc -q4 -oMyMovie-add-audio.ogg MyMovie-add-audio.wav
$ ogmmerge-o MM-complete.ogm MyMovie-with-sound.ogm MyMovie-add-
audio.ogg
The same result can be achieved with
$ ogmmerge-o MM-complete.ogm -A MyMovie.avi MyMovie.ogg \
MyMovie-add-audio.ogg
Now fire up mplayer and enjoy. If you have multiple audio tracks (or
even video tracks) then you can tell mplayer which track to play with
the '-vid' and '-aid' parameters. These are 0-based and do not distin‐
guish between video and audio.
If you need an audio track synchronized you can do that easily with
$ ogmmerge-o goodsync.ogm -A source.avi -s 200 outofsync.ogg
This would add 200ms of silence at the beginning of the audio tracks
taken from outofsync.ogg. And -s always applies to all audio tracks in
a source file. If you want to apply -s only to a specific track then
take the same source file more than once and add -a and -s accordingly.
Some movies start synced correctly but slowly drift out of sync. For
these kind of movies you can specify a delay factor that is applied to
all timestamps - no data is added or removed. So if you make that fac‐
tor too big or too small you'll get bad results. An example is that an
episode I transcoded was 0.2 seconds out of sync at the end of the
movie which was 77340 frames long. At 29.97fps 0.2 seconds correspond
to approx. 6 frames. So I did
$ ogmmerge-o goodsync.ogm -s 0,77346/77340 outofsync.ogm
The result was fine.
The sync options can also be used for subtitles in the same manner.
For text subtitles you can either use some Windows software (like Sub‐
Ripper) or the subrip package found in transcode(1)'s sources (in con‐
trib/subrip). The general process is:
1. extract a raw subtitle stream from the source:
$ tccat -i /path/to/copied/dvd/ -T 1 -L | \
tcextract -x ps1 -t vob -a 0x20 | \
subtitle2pgm -o mymovie
2. convert the resulting PGM images to text with gocr:
$ pgm2txt mymovie
3. spell-check the resulting text files:
$ ispell -d american *txt
4. convert the text files to a SRT file:
$ srttool -s -w -i mymovie.srtx -o mymovie.srt
The resulting file can be used as another input file for ogmmerge:
$ ogmmerge-o mymovie.ogm -c 'TITLE=My Movie' mymovie.avi \
-c LANGUAGE=English mymovie.ogg -c LANGUAGE=English mymovie.srt
FILE SIZE
Using OGG as the container format introduces overhead - each OGG packet
has a header, and each OGG packet can span one or more OGG pages, which
itself again contain headers. Several tests show that the overhead is
bigger than the overhead introduced by AVI (comparing video only files
and files with video and MP3 audio).
The overhead is defined as file size - raw stream size. mencoder
prints the raw stream size after encoding, so you'll be able to get
that information rather easily.
Most of the times you want to calculate the overhead prior to encoding
in order to adjust the bitrate accordingly. Unfortunately the overhead
per frame is not constant - only the percentage is constant. This per‐
centage is calculated as 100 * (OGG size - raw size) / raw size and
seems to be somewhere between 1.1% and 1.2%. This depends on the number
of streams and the stream types used.
The raw size itself can be approximated by
frames * vbitrate
raw size = ( ----------------- + length * abitrate ) / 8 * 1000 * 1024
frames per sec
assuming that vbitrate and abitrate are given in kbit/s = 1000 bit/s,
and length is given in seconds.
NOTES
What works:
* AVI as the video and audio source (currently only raw PCM, MP3
and AC3 audio tracks)
* OGG as the source for video, audio (Vorbis, raw PCM, MP3 and AC3
audio) and text streams (subtitles).
* WAV as the audio source
* MP3 audio files
* AC3 audio files
* Track selection
* Manual audio synchronization by adding silence/removing packets
for Vorbis audio and for text streams by adjusting the starting
point and duration.
* Manual audio synchronization for AC3 and MP3 audio by duplicat‐
ing/removing packets at the beginning.
* Adding user comments to the mandatory comment headers (only the
headers are mandatory. Comments themselves are not mandatory.)
* Text subtitles can be read from SRT (SubRipper / subrip) and
MicroDVD files or taken from other OGM files.
* PCM, AC3 and MP3 audio work well under Windows and with MPlayer
now.
* Chapter information as generated by dvdxchap are supported.
What not works:
* Manual audio synchronization for PCM sound (who needs it any‐
way?)
Planned functionality:
* support for other subtitle formats
CHAPTERSogmmerge supports chapter information as generated by dvdxchap(1). The
format is very simple:
CHAPTER01=HH:MM:SS.sss
CHAPTER01NAME=the first chapter
CHAPTER02=HH:MM:SS.sss
CHAPTER02NAME=another chapter
with HH = hour, MM = minute, SS = seconds, sss = milliseconds.
The chapter information is stored in the video stream's comments.
Therefore you could also specify the chapters with -c CHAPTER01=...
Using a chapter file has an advantage: If the video stream's comments
already contain chapter information and the command line contains a
chapter information file then the existing chapter information will be
completely replaced.
TECHNICAL ASPECTS
This section is not needed by the average user.
ogmmerge consists of three parts:
* Demultiplexers (called readers) open and read input files speci‐
fied on the command line and extract specific tracks.
* Packetizers (or output modules) take data from a demultiplexer
and encapsulate them into OGG pages. These are stored in queues.
* The main program requests from every known demultiplexer that it
should read some data. It then gets the OGG page with the small‐
est timestamp from all the packetizer queues. This page is writ‐
ten to the output file.
The general class definitions for the readers and the packetizers can
be found in ogmmerge.h.
The main loop expects that the queues managed by the demuxer's packe‐
tizers are filled with at least one page after a call to the demuxer's
read() function. The demuxer must make sure that enough data is passed
to each of its associated packetizers. Have a look at r_ogm.cpp.
A possible setup might look like this:
+-> p_video
+-> r_avi -+
| +-> p_pcm
|
ogmmerge -+-> r_ogm ---> p_vorbis
|
| +-> p_video
| |
+-> r_ogm -+-> p_vorbis
|
+-> p_vorbis
One AVI source with a video and an audio track, one OGG/OGM source with
only one Vorbis track, another OGG/OGM source with a video and two Vor‐
bis tracks.
AUTHORogmmerge was written by Moritz Bunkus <moritz@bunkus.org>.
SEE ALSOogmdemux(1), ogmsplit(1), ogminfo(1), ogmcat(1), dvdxchap(1)WWW
The newest version can always be found at
<http://www.bunkus.org/videotools/ogmtools/>
⟨http://www.bunkus.org/videotools/ogmtools/⟩
ogmmerge v1.5 November 2004 OGMMERGE(1)
