====== Appunti Avidemux ======
* [[http://avidemux.berlios.de/]]
* [[http://www.vcdhelp.com/]]
* [[http://www.doom9.net/]]
===== Precompiled binariers =====
I suggest to download and install the Debian package from this deb repository:
deb ftp://ftp.nerim.net/debian-marillat etch main
===== Compiling Avidemux =====
To get the source tree from CVS, configure and compile the program:
cvs -d:pserver:anonymous@cvs.berlios.de:/cvsroot/avidemux login
cvs -d:pserver:anonymous@cvs.berlios.de:/cvsroot/avidemux co avidemux
cd avidemux
make -f Makefile.dist
./configure
make
To build the ''Makefile'' you need at least these Debian packages:
* cvs
* autoconf
* libxml2-dev
Several packages are needed to compile support for various video and audio formats into Avidemux. Most of this packages are provided for Debian by Marillat at [[ftp://ftp.nerim.net/debian-marillat/]].
^ Package ^ Reported by Avidemux as ^ Function ^ Provided by ^
| | Xvid 0.9 Codec | Video Codec XviD (obsolete) | |
| *libxvidcore4-dev* | Xvid 1.0 Codec | Video Codec XviD | Marillat |
| *libvorbis-dev* | Ogg Vorbis | Audio Codec Ogg Vorbis | Debian |
| *liblame-dev* | Lame | Audio Codec MP3 | Marillat |
| *libfaac-dev* | Faac (encoder) | Audio Encoder AAC | Marillat |
| *libfaad2-dev* | Faad2(decoder) | Audio Decoder AAC | Marillat |
| *libmad0-dev* | Mad decoder | Audio Decoder MPEG | Debian |
| *liba52-0.7.4-dev* | A52/AC3 | Audio Decoder A52/AC3 | Debian |
| | Xvideo | | |
| | SDL | | |
| | ALSA | | |
| | ARTS | | |
===== Video Codecs Availables in Avidemux =====
For creating **.avi** files, my suggestion is to use the **XviD** video encoder. It is based on Free Software and it gives amazing quality also at low bitrates. Movies encoded with the //two pass// method can fit in a single CD with minimal quality loss respect a VHS tape. Support by players seems rather good, but beware of some advanced options like Q-PEL.
== Xvid4 ==
It produces [[glossary#xvid|XviD]] (ISO MPEG-4 compliant) video files. Requires ''**libxvidcore.so.4**'' provided by the ''libxvidcore4'' package by [[ftp://ftp.nerim.net/debian-marillat/|Marillat]]. The code is Free Software released under the GPL license, see [[http://www.videocoding.de/]]. Patent issues on some XviD features, prevent the package to be included in Debian.
== Mjpeg ==
== VCD ==
== SVCD ==
== DVD ==
== XVCD ==
== XSVCD ==
== SVCD (lavc) ==
== DVD (lavc) ==
== Lav Mpeg4 ==
It produces ISO MPEG-4 compliant video files. Requires the ''**libavcodec**'' library provided by the ''libavcodec2'' or the ''libavcodeccvs'' packages by [[ftp://ftp.nerim.net/debian-marillat/|Marillat]]. Also known as **lavc**, it is another Open Source MPEG4 compliant video codec which is superior in performance and quality to DivX 5 and even to XviD. This codec starts to support b-frames*. It is part of the ffmpeg project.
== H263 ==
== H263+ ==
== Huffyuv ==
== FFV1 ==
== Snow ==
===== Audio Codecs Availables in Avidemux =====
After installing Avidemux on my Debian GNU/Linux system, several audio codecs were availables. For creating **.avi** files, my suggestion is to use the **Lame encoder**; for its quality and the wide support by players. If you are concerned about patent issues on mp3 format, choose **Ogg Vorbis** instead.
A brief summary to help choose one.
== Lame ==
It produces MPEG-1 Layer 3 ([[glossary#mp3|mp3]]) files. Requires ''**libmp3lame.so**'', provided by the ''liblame0'' package by [[ftp://ftp.nerim.net/debian-marillat/|Marillat]]. The program can also pipe to an external lame program (menu Misc, Preferences, LAME). The source code is from the ''lame'' package, released under the GPL license, see [[http://www.mp3dev.org/]]. It seems that there are some patent issues that prevent the package to be included into the Debian distribution. See a [[http://www.debian.org/devel/wnpp/unable-to-package|discussion]] about including Lame into Debian.
Supported modes: Mono, Stereo and [[glossary#jointstereo|Joint Stereo]]. Supported rates: 48-384 kbits [[glossary#cbr|CBR]], [[glossary#abr|ABR]] and Extreme (aggressive [[glossary#vbr|VBR]]).
== Vorbis ==
It produces [[glossary#ogg_vorbis|Ogg Vorbis]] audio files. Requires ''**libvorbisenc.so.2**'', provided by the ''libvorbisenc2'' Debian package. This audio format was developed as a Free Software replacement for mp3, where some patent issues perist. Sound quality is comparable (if not better) than mp3, support from players is less ubiquitous, but increasing.
Supported modes: Stereo and [[glossary#jointstereo|Joint Stereo]]. Supported rates: 48-384 kbits. [[glossary#cbr|CBR]]? [[glossary#abr|ABR]]?
== FAAC ==
It produces [[glossary#aac|AAC]] audio files. Requires ''**libfaac.so.0**'' and ''**libfaad.so.0**'' (encoder and decoder), provided by the ''libfaac0'' and ''libfaad2-0'' packages by [[ftp://ftp.nerim.net/debian-marillat/|Marillat]]. The site is [[http://www.audiocoding.com/]] .Source code is available under the GPL or LGPL license so it is Free Software, but some patent issues exist on this audio format.
Supported modes: Stereo and [[glossary#joint_stereo|Joint Stereo]]. Supported rates: 48-384 kbits. [[glossary#cbr|CBR]].
== FFm MP2 ==
It produces MPEG-1 layer 2 ([[glossary#mp2|mp2]]) files. The support is statically compiled-in using the **libavcodec** library. The source code of this codec is from the ffmpeg project ([[http://ffmpeg.sourceforge.net/]]), licensed under the LGPL license. Some patent issues concern this software, as other MPEG related software. See [[http://ffmpeg.sourceforge.net/legal.php]].
Most ffmpeg codecs were developped from scratch to ensure best performances and high code reusability. Don't know how it compares with TooLAME. Supported modes: Stereo and Joint Stereo. Supported rates: 48-384 kbits. CBR Only?
== FFm AC3 ==
It produces [[glossary#ac-3|AC-3]] audio streams. Most DVD have the audio encoded in some AC-3 variant. The support is statically compiled-in using the **libavcodec** library, see FFm MP2 for some notes about the ffmpeg project.
== Toolame ==
It produces MPEG-1 layer 2 ([[glossary#mp2|mp2]]) files. The support is statically compiled in, or the program can pipe to an external toolame program (menu Misc, Preferences, tooLAME). Because of patent issues surrounding the layer 3 encoder and the ability of most mpeg audio players to play layer 2 files, toolame makes a very good drop-in replacement for lame or other layer 3 encoders under most circumstances. Don't know how it compares with FFm MP2.
Supported modes: Stereo and [[glossary#joint_stereo|Joint Stereo]]. Supported rates: 48-384 kbits [[glossary#cbr|CBR]].
== Wav PCM ==
It produces uncompressed Microsoft RIFF Wav PCM audio files.
===== Video filters =====
== Mplayer resize ==
== Resize ==
Works great. Many DVD movies have rectangular pixels, I use this filter to resize to the proper aspect ratio. It is common practice to have width and height exact multiples of 16.
* **Bilinear**: Tends to smooth the picture, but makes the video easier to encode. Appropriate for downsizing.
* **Bicubic**: Keeps sharpness and thus makes the video harder to encode (leads more easily to blocking-artifacts). Recommended for enlarging.
* **Lanczos**: Produces a very sharp picture and keeps a lot of details. Use it for HQ encodings at high bitrates.
== Deinterlace ==
== Lavcodec PP deinterlacer ==
Works great. Many DVD originating from a PAL video source need to be deinterlaced. Apply the deinterlace filter before the resize one. **Cubic Interpolation** seems to be the best, Median Deinterlacer also works well.
^ Filter ^^
^ Linear Blend | Deinterlaces the given block by filtering all lines with a (1 2 1) filter. |
^ Linear interpolation | Deinterlaces the given block by linearly interpolating every second line. |
^ Cubic interpolation | Deinterlaces the given block by cubically interpolating every second line. |
^ Median Deinterlacer | Deinterlaces the given block by applying a median filter to every second line. |
^ FFmpeg Deinterlacer | Deinterlaces the given block by filtering every second line with a (-1 4 2 4 -1) filter. |
Changing **Autolevel** setting in Avidemux 2.0.40 may crash, you have to apply this patch: [[http://www.avidemux.org/phpBB2/viewtopic.php?t=1220]].
== VobSub ==
VobSub is a well known subtitle format that saves subtitles nearly in the same format as it appears in DVD subtitle streams. From a technical point of view, VobSub saves subtitles as little images.
This filter overlays subtitles to the video, it takes the subtitles from two files, one ''**.sub**'' and one ''**.idx**''. Useful when ripping a DVD and you want to get the subtitles overlayed statically. Is otherwise generally preferable to keep subtitles in a separate file, in text or bitmap format, and let the player to overlay them at play time.
See the [[transcode]] page on howto extract VobSub subtitles from a DVD-Video. You can also use [[mplayer#mencoder|mencoder]] to accomplish the same operation.
===== Audio filters =====
== Time shift ==
Playing a video with **mplayer** you can find that audio and video are not in sync, then you can adjust sync with the ''**+**'' and the ''**-**'' keys.
To fix the sync permanently open the file with Avidemux and apply this filter, this is the only filter to work also in copy mode. This filter shifts the audio by removing the beginning or duplicating to create new sound.
Shift is expressed in ms, note that a negative delay in Mplayer must be expressed as a positive value in Avidemux, and viceversa.
See also [[transcode#avisync|avisync]] for a command line tool to adjust audio/video syncronization.
== Resampling ==
Sometimes resampling the audio is necessary beacuse the destination codec has some restrictions. This is the case of AVI files produced by some cameras, which encode audio in PCM 8 bits, mono, 11024 Hz. Trying to re-encode the audio with Lame into mp3, produces the error message **Encoder initialization failed**, **Not activated**. It is necessary to resample the audio to 48000 or 44100 Hz.
===== Modifica Audio con programmi esterni =====
Si può usare un programma esterno come Audacity per editare l'audio, bisogna però "estrarlo" dal filmato originale.
Avidemux avrebbe questa funzione dal menu //Audio//, //Save//, ma il file salvato è in formato raw e quindi per aprirlo in Audacity bisogna specificare tutti i parametri e soprattutto **viene tagliato male alla fine, perdendo alcuni decimi di secondo** (Avidemux v. 2.5.4). Per questo motivo è meglio utilizzare **''mplayer''** che sembra molto più adatto allo scopo:
mplayer -ao pcm:file=audio.wav -vo null file.avi
Una volta aperto il file con Audacity ricordarsi di impostare il //Project Rate// (in basso a sinistra) ad una frequenza compatibile con il codec che si vorrà usare, ad esempio per lame mp3 una frequenza compatibile è 44100 Hz. Alla fine esportare il file audio in formato accettato da Avidemux, ad esempio WAV PCM.
Una volta ottenuto il file audio, si provvede a fare il mux con il video e l'encoding nel formato finale con Avidemux:
- Aprire il filmato
- Dal menu Audio, Main Track caricare la traccia audio elaborata
- Impostare il codec video e gli eventuali filtri
- Impostare il codec audio
- Salvare il nuovo filmato
===== Frame types =====
^ Type ^ What is it ^
^ I | Intra-coded frames, average 7:1 reduction. Like JPEG, every video frame is broken into blocks of 8x8 pixels of Y, R-Y, and B-Y |
^ P | P frames are predicted based on prior I or P frames plus the addition of data for changed macroblocks. Average about 20:1 reduction, or about half the size of I frames. |
^ B | Bidirectionally predicted frames based on appearance and positions of past and future frames macroblocks. B frames require less data than P frames, averaging about 50:1 reduction. B frames require more decoder buffer memory because 2 frames are compared during the reconstruction process. B frames also require manipulation of the coding order: frames moving from the coder to the decoder are NOT in presentation sequence. |