Encoding with MEncoder
For the complete list of available MEncoder options
and examples, please see the man page. For a series of hands-on examples and
detailed guides on using several encoding parameters, read the
encoding-tips that were
collected from several mailing list threads on mplayer-users. Search the
archives
for a wealth of discussions about all aspects of and problems related to
encoding with MEncoder.
Encoding 2 or 3-pass MPEG-4 ("DivX")2-pass encoding
The name comes from the fact that this method encodes the file twice.
The first encoding (dubbed pass) creates some temporary files
(*.log) with a size of few megabytes, do not delete
them yet (you can delete the AVI). In the second pass, the 2-pass output
file is created, using the bitrate data from the temporary files. The
resulting file will have much better image quality. If this is the first
time you heard about this, you should consult some guides available on the
Net.
This example shows how to encode a DVD to a 2-pass MPEG-4 ("DivX") AVI.
Just two commands are needed:
rm frameno.avi
remove this file, which can come from a previous 3-pass encoding (it interferes
with current one)
mencoder dvd://2 -ovc lavc -lavcopts vcodec=mpeg4:vpass=1 -oac copy -o movie.avi
mencoder dvd://2 -ovc lavc -lavcopts vcodec=mpeg4:vpass=2 -oac copy -o movie.avi3-pass encoding
This is an extension of 2-pass encoding, where the audio encoding takes
place in a separate pass. This method enables estimation of recommended
video bitrate in order to fit on a CD. Also, the audio is encoded only
once, unlike in 2-pass mode. The schematics:
Remove conflicting temporary file:
rm frameno.aviFirst pass:mencoder file/DVD -ovc frameno -oac mp3lame -lameopts vbr=3 -o frameno.avi
An audio-only avi file will be created, containing
only the requested audio stream. Don't forget
, if you need to set it. If you were encoding a
long movie, MEncoder prints the recommended
bitrate values for 650Mb, 700Mb, and 800Mb destination sizes, after this
pass finishes.
Second pass:
mencoder file/DVD -oac copy -ovc lavc -lavcopts vcodec=mpeg4:vpass=1:vbitrate=bitrate
This is the first pass of video encoding. Optionally specify the video
bitrate MEncoder printed at the end of the previous pass.
Third pass:
mencoder file/DVD -oac copy -pass 2 \
-ovc divx4 -divx4opts br=bitrate
This is the second pass of video encoding. Specify the same bitrate
as in the previous pass unless you really know what you are doing.
In this pass, audio from frameno.avi will be
inserted into the destination file...and it's all ready!
Example of 3-pass encodingrm frameno.avi
remove this file, which can come from a previous 3-pass encoding
(it interferes with current one)
mencoder dvd://2 -ovc frameno -o frameno.avi -oac mp3lame -lameopts vbr=3
mencoder dvd://2 -ovc lavc -lavcopts vcodec=mpeg4:vpass=1 -oac copy -o movie.avi
mencoder dvd://2 -ovc lavc -lavcopts vcodec=mpeg4:vpass=2 -oac copy -o movie.aviEncoding to MPEG formatMEncoder can create MPEG (MPEG-PS) format output
files. It's probably useful only with libavcodec's
mpeg1video codec, because players - except
MPlayer - expect MPEG1 video, and MPEG1 layer 2 (MP2)
audio streams in MPEG files.
This feature is not very useful right now, aside that it probably has many bugs,
but the more importantly because MEncoder currently
cannot encode MPEG1 layer 2 (MP2) audio, which all other players expect in MPEG files.
To change MEncoder's output file format,
use the option.
Example:
mencoder -of mpeg -ovc lavc -lavcopts vcodec=mpeg1video -oac copy other_optionsmedia.avi -o output.mpgRescaling movies
Often the need to resize movie images' size emerges. Its reasons can be
many: decreasing file size, network bandwidth,etc. Most people even do
rescaling when converting DVDs or SVCDs to DivX AVI. This is bad.
Instead of even you doing so, read the Preserving aspect ratio
section.
The scaling process is handled by the scale video filter:
.
Its quality can be set with the option.
If it's not specified, MEncoder will use 0: fast
bilinear.
Usage:
mencoder input.mpg -ovc lavc -lavcopts vcodec=mpeg4 -vf scale=640:480-o output.aviStream copyingMEncoder can handle input streams in two ways:
encode or copy
them. This section is about copying.
Video stream (option ):
nice stuff can be done :) Like, putting (not converting!) FLI or VIVO or
MPEG1 video into an AVI file! Of course only
MPlayer can play such files :) And it probably
has no real life value at all. Rationally: video stream copying can be
useful for example when only the audio stream has to be encoded (like,
uncompressed PCM to MP3).
Audio stream (option ):
straightforward. It is possible to take an external audio file (MP3,
WAV) and mux it into the output stream. Use the
option
for this.
Fixing AVIs with broken index or interleaving
Easiest thing. We simply copy the video and audio streams, and
MEncoder generates the index. Of course this cannot fix possible bugs in
the video and/or audio streams. It also fixes files with broken interleaving,
thus the option won't be needed for them anymore.
Command:
mencoder -idx input.avi -ovc copy -oac copy -o output.aviAppending multiple AVI files
As a side-effect, the broken AVI fixer function enables MEncoder
to append 2 (or more) AVI files:
Command:
cat 1.avi 2.avi | mencoder -noidx -ovc copy -oac copy -o output.avi -
This expects 1.avi and 2.avi to use
the same codecs, resolution, stream rate etc, and at least 1.avi
must not be broken. You may need to fix your input AVI files first, as described
above.
Encoding with the libavcodec codec family
libavcodec provides simple encoding to a lot
of interesting video and audio formats.
You can encode to the following codecs (more or less up to date):
Codec nameDescriptionmjpeg
Motion JPEG
ljpeg
Lossless JPEG
h263
H263
h263p
H263 Plus
mpeg4
ISO standard MPEG-4 (DivX 5, XVID compatible)
msmpeg4
pre-standard MPEG-4 variant by MS, v3 (aka DivX3)
msmpeg4v2
pre-standard MPEG-4 by MS, v2 (used in old asf files)
wmv1
Windows Media Video, version 1 (aka WMV7)
wmv2
Windows Media Video, version 2 (aka WMV8)
rv10
an old RealVideo codec
mpeg1video
MPEG1 video
mpeg2video
MPEG2 video
huffyuv
lossless compression
asv1
ASUS Video v1
asv2
ASUS Video v2
ffv1
FFmpeg's lossless video codec
The first column contains the codec names that should be passed after the
vcodec config, like:
An example, with MJPEG compression:
mencoder dvd://2 -o title2.avi -ovc lavc -lavcopts vcodec=mjpeg -oac copyEncoding from multiple input image files (JPEGs,PNGs or TGAs)MEncoder is capable of creating movies from one
or more JPEG, PNG or TGA files. With simple framecopy it can create MJPEG
(Motion JPEG), MPNG (Motion PNG) or MTGA (Motion TGA) files.
Explanation of the process:MEncoderdecodes the input image(s) with
libjpeg (when decoding PNGs, it
will use libpng).
MEncoder then feeds the decoded image to the
chosen video compressor (DivX4, Xvid, ffmpeg msmpeg4, etc.).
Examples
The explanation of the option can be found below in
the man page.
Creating a DivX4 file from all the JPEG files in the current dir:
mencoder -mf on:w=800:h=600:fps=25 -ovc divx4 -o output.avi \*.jpg
Creating a DivX4 file from some JPEG files in the current dir:
mencoder -mf on:w=800:h=600:fps=25 -ovc divx4 -o output.aviframe001.jpg,frame002.jpg
Creating a Motion JPEG (MJPEG) file from all the JPEG files in the current
dir:
mencoder -mf on:w=800:h=600:fps=25 -ovc copy -o output.avi \*.jpg
Creating an uncompressed file from all the PNG files in the current dir:
mencoder -mf on:w=800:h=600:fps=25:type=png -ovc raw -o output.avi \*.png
Width must be integer multiple of 4, it's a limitation of the RAW RGB AVI format.
Creating a Motion PNG (MPNG) file from all the PNG files in the current
dir:
mencoder -mf on:w=800:h=600:fps=25:type=png -ovc copy -o output.avi \*.png
Creating a Motion TGA (MTGA) file from all the TGA files in the current
dir:
mencoder -mf on:w=800:h=600:fps=25:type=tga -ovc copy -o output.avi \*.tgaExtracting DVD subtitles to Vobsub fileMEncoder is capable of extracting subtitles from
a DVD into Vobsub formatted files. They consist of a pair of files ending in
.idx and .sub and are usually
packaged in a single .rar archive.
MPlayer can play these with the
and options.
You specify the basename (i.e without the .idx or
.sub extension) of the output files with
and the index for this subtitle in the
resulting files with .
If the input is not from a DVD you should use to
indicate the .ifo file needed to construct the
resulting .idx file.
If the input is not from a DVD and you do not have the
.ifo file you will need to use the
option to let it know what language id to put in
the .idx file.
Each run will append the running subtitle if the .idx
and .sub files already exist. So you should remove any
before starting.
Copying two subtitles from a DVD while doing 3-pass encoding
rm subtitles.idx subtitles.sub
mencoder dvd://1 -vobsubout subtitles -vobsuboutindex 0 -sid 2 -o frameno.avi -ovc frameno
mencoder dvd://1 -oac copy -ovc divx4 -pass 1
mencoder dvd://1 -oac copy -ovc divx4 -pass 2 -vobsubout subtitles -vobsuboutindex 1 -sid 5Copying a french subtitle from an MPEG file
rm subtitles.idx subtitles.sub
mencoder movie.mpg -ifo movie.ifo -vobsubout subtitles -vobsuboutindex 0 -vobsuboutid fr -sid 1Preserving aspect ratio
DVDs and SVCDs (i.e. MPEG1/2) files contain an aspect ratio value, which
describes how the player should scale the video stream, so humans won't
have egg heads (ex.: 480x480 + 4:3 = 640x480). However when encoding to AVI
(DivX) files, you have be aware that AVI headers don't store this value.
Rescaling the movie is disgusting and time consuming, there has to be a better
way!
There is
MPEG4 has an unique feature: the video stream can contain its needed aspect
ratio. Yes, just like MPEG1/2 (DVD, SVCD) and H263 files. Regretfully, there are
no video players outside which support this
attribute of MPEG4, except MPlayer.
This feature can be used only with libavcodec's
mpeg4 codec. Keep in mind: although
MPlayer will correctly play the created file,
other players will use the wrong aspect ratio.
You seriously should crop the black bands over and below the movie image.
See the man page for the usage of the cropdetect and
crop filters.
Usage
mencoder sample-svcd.mpg -ovc lavc -lavcopts vcodec=mpeg4:autoaspect -vf crop=714:548:0:14 -oac copy -o output.aviCustom inter/intra matrices
With this feature of libavcodec you are
able to set custom inter (I-frames/key frames) and intra (P-frames/predicted
frames) matrices. It is supported by many of the codecs:
mpeg1video and mpeg2video
are reported as working.
A typical usage of this feature is to set the matrices preferred by the
KVCD specifications.
The KVCD "Notch" Quantization Matrix:
Intra:
8 9 12 22 26 27 29 34
9 10 14 26 27 29 34 37
12 14 18 27 29 34 37 38
22 26 27 31 36 37 38 40
26 27 29 36 39 38 40 48
27 29 34 37 38 40 48 58
29 34 37 38 40 48 58 69
34 37 38 40 48 58 69 79
Inter:
16 18 20 22 24 26 28 30
18 20 22 24 26 28 30 32
20 22 24 26 28 30 32 34
22 24 26 30 32 32 34 36
24 26 28 32 34 34 36 38
26 28 30 32 34 36 38 40
28 30 32 34 36 38 42 42
30 32 34 36 38 40 42 44
Usage:
$ mencoder input.avi -o output.avi -oac copy -ovc lavc -lavcopts inter_matrix=...:intra_matrix=...
$ mencoder input.avi -ovc lavc -lavcopts
vcodec=mpeg2video:intra_matrix=8,9,12,22,26,27,29,34,9,10,14,26,27,29,34,37,
12,14,18,27,29,34,37,38,22,26,27,31,36,37,38,40,26,27,29,36,39,38,40,48,27,
29,34,37,38,40,48,58,29,34,37,38,40,48,58,69,34,37,38,40,48,58,69,79
:inter_matrix=16,18,20,22,24,26,28,30,18,20,22,24,26,28,30,32,20,22,24,26,
28,30,32,34,22,24,26,30,32,32,34,36,24,26,28,32,34,34,36,38,26,28,30,32,34,
36,38,40,28,30,32,34,36,38,42,42,30,32,34,36,38,40,42,44 -oac copy -o svcd.mpg
Making a high quality MPEG4 ("DivX") rip of a DVD movie
Ripping a DVD title into a maximally high quality MPEG4 (DivX) file
involves many considerations. Below is an example of the process when
there is no file size goal (other than perhaps fitting the result into 2GB).
libavcodec will be used for the video,
and the audio will be copied as is without any changes.
Cropping
Play the DVD and run the crop detection filter
() on it. This gives you a crop rectangle
to use for encoding. The reason for cropping is that many movies are
not shot in a standard DVD aspect ratio (16/9 or 4/3), or, for whatever
reason, the picture does not properly fill the frame. So you want to crop
out the pointless black bars when you rip. It also improves the quality
of the rip since the sharp edge of the black bars wastes a lot of bits.
A common aspect is 2.35, which is cinescope. Most big blockbuster
movies have this aspect ratio.
Quality level
Next you need to choose the desired quality level. When there is no
need to fit the resulting file on CDs or the like, using constant
quantizing AKA constant quality is a good choice. That way each frame
is given as much bits as its needs to keep the quality at the desired
level, but multiple encoding passes are not needed. With
libavcodec, you get constant
quality by using
.
should give you a file below 2GB in size,
depending mainly on the movie length and video noisiness (the more
noise, the harder it is to compress.)
Files over 2GB
If the file resulting from constant quality encoding is over 2GB big,
you will have to create an index to be able to view it properly.
Either
play the file with to create an index
on the fly or
use to write an index to a file once and
to use it when playing the file.
If this bothers you, you may want to keep the file size below 2GB.
There are three ways to avoid this. You can try encoding again using
and see if both the resulting file size
and picture quality are acceptable. You can also use
2 pass encoding.
As you will be copying the audio track as is and hence know its
bitrate, and you know the running time of the movie, you can
compute the required bitrate to give to the
option without using
3 pass encoding.
The third and possibly the best option may be to slightly scale down
the resolution. The uniform slight softening and loss of detail is
visually more appealing than the blockiness and other artifacts
caused by MPEG compression. Scaling down also effectively reduces the
noise of the picture, which is good, as noise is hard to compress.
Deinterlacing
If the movie is interlaced, you may want to deinterlace it as part of
the ripping. It is debatable whether deinterlacing should be done at
this stage. The benefit is that deinterlacing when converting to
MPEG4 makes compression better, and viewing easier and less CPU
intensive on computer monitors as no deinterlacing is required at
that stage.
If deinterlacing at the ripping stage is a good idea depends on
the DVD. If the DVD is made from film, which was shot at 24 fps, you
can as well deinterlace while ripping. If, however, the original was
50/60 fps video, converting into deinterlaced 23.976/25 fps video
will lose information. If you do decide to interlace, you can further
experiment with different deinterlacing filters. See
http://www.wieser-web.de/MPlayer/
for examples. A good starting point is .
If you are both cropping and deinterlacing, deinterlace
before cropping. Actually, this is not necessary
if the crop offset is vertically a multiple of 2 pixels. However with
some other filters like dering you should always crop last, so it's a
good habit to put the crop filter last.
Inverse telecine
If you are ripping a PAL DVD, which is 25 fps, you do not need to
think about the fps. Just use 25 fps. NTSC DVDs on the other hand are
29.97 fps (often rounded to 30 fps, but that is not what they are).
If the movie was shot for TV, you again do not need to touch the fps.
But if the movie was shot on film, and hence at (exactly) 24 fps,
it has been converted to 29.97 fps when making the DVD. That
conversion where 12 fields are added to each 24 frames of film is
called telecine. For more info about telecine, see a
Google search for "telecine field 23.976".
In case you have such a telecined DVD, you will want to do inverse
telecine, that is convert the movie to 23.976 fps (29.97*4/5).
Otherwise camera panning will look jerky and awful. You can use
for this. Anything that is shown in
theatres is shot on film and needs inverse telecine, TV shows do not.
Scaling and aspect ratio
For best quality, do not scale the movie while ripping. Scaling down
obviously loses detail, and scaling up causes artifacts and obviously
makes the file larger. Pixels in DVD movies
are not square, so DVD movies include info about the correct aspect
ratio. It is possible to store the aspect ratio in the MPEG4 header
of the output file. Most video players ignore this info, but
MPlayer honors it. So if you are only
going to use MPlayer for viewing the
ripped file, you do not need to scale the movie, just pass
to
MEncoder and things will
automagically work right. If you must scale the movie, be
careful about getting the size right especially if you do cropping.
Summing it up
With all of the above mentioned in mind, a suitable encoding command
might be
mencoder dvd://1 -aid 128 -oac copy -ovc lavc -lavcopts vcodec=mpeg4:vqscale=3:vhq:v4mv:trell:autoaspect \
-ofps 23.976 -vf crop=720:364:0:56 -o Harry_Potter_2.avi
Here gives the DVD title to rip. Option
says to use audio track 128, and
to copy it as is. You'll have to use
MPlayer to find out the right values for
these options.
Options for
improve quality versus bitrate, but make
encoding take longer. Especially slows
encoding down but also increases quality visibly. If you want to
deinterlace, add a filter to
, for example
(in that order). If you don't need
inverse telecine, leave out the .