TRANSCODERS

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Project Overview

Codecs_Research

Project Workspace

Codecs_Workspace

Client side transcoder

Research Question:

What desktop tools currently exist that support encoding to open source codecs? 

What would be needed to implement it into current FOSS transcoding applications such as Media Coder, 
ffmpegx, Virtual Dub and Gtranscode.
  • note from Jaromil - i'd rather address development of clean encoder/decoder examples for software developers in various languages, in form of libraries maybe, as well direct support to the FFMpeg project.
  • from mick fuzz - investigate easy to use presets for encoders - asking popular encoder developers to package an easy preset for Ogg Theora/Vorbis with their applications


ffmpeg2theora Theora/Vorbis CLI - CROSS PLATFORM

Ogg Support? Yes

ffmpeg2theora cross platform encoder from J

Installed on Mac os x 10.3 on Anna's powerbook as part of frontend. Ran on bash terminal successfully and transcoded succesfully.

Consult this wiki page for some help on this area for other mac users ffmpeg2theora_mac

ffmpeg2theora GUI - MAC (currently)

Ogg Theora/Vorbis Support? Yes

In early stages of development. See this wiki page for more details:

http://wiki.transmission.cc/index.php/FFMPEG2THEORA

VLC - CROSS PLATFORM

Ogg Theora/Vorbis Support? Yes

VideoLanClient is a great FOSS cross-platform media player. However, according to the VLC website it is not an ideal file to file transcoder, but does the job.

It is hard to establish what is meant by "not ideal" - perhaps this is referring to efficiency, or to lack of transcoding options?

http://www.videolan.org/

Test 1 - 29 May 2007

Setup

  • Encoding computer - Mac Powerbook 1.33 GHz PowerPC G4, 1.25 GB DDR SDRAM, OS X 10.3.9
  • VLC Version - 0.8.6
  • Input File - Abstractor-Billboard.mp4 (H264 / AAC audio)
  • 7.9 MB
  • Duration 1 minute 53 seconds
  • Dimensions 550 x 366
  • Used preset - only selected "Theora", "Vorbis", "Ogg" in Wizard

Results

  • Encoding Time - Real time
  • Good quality
  • Incorrect frame-size... was vertically squished

Test 2 - 29 May 2007

Setup

  • Encoding computer - Mac Powerbook 1.33 GHz PowerPC G4, 1.25 GB DDR SDRAM, OS X 10.3.9
  • VLC Version - 0.8.6
  • Input File - bigtime.mov (Quicktime Sorenson 3, AAC Audio)
  • 7.9 MB
  • Duration 1 minute 40 seconds
  • Dimensions 320 x 240
  • Used preset - only selected "Theora", "Vorbis", "Ogg" in Wizard

Results

  • Encoding Time - Faster than real time
  • Good quality
  • Correct frame-size

Conclusion

A very small test, so hardly representative, but showed that good results are possible with VLC, though there may be some errors in transcoding.

Media Coder - WINDOWS

 Ogg Theora/Vorbis Support? Yes

MediaCoder is a much more user-friendly transcoder than Virtual Dub, authored primarily by Stanley Huang.

http://mediacoder.sourceforge.net/index.htm

From the website:

"MediaCoder is a free universal audio/video batch transcoder distributed under GPL license, which nicely integrates lots of excellent audio/video codecs and tools from the open source community into an all-in-one solution, capable of transcoding among different audio/video formats. With many extra features and a expandable architecture, MediaCoder is more than a GUI of a bunch of command line tools.

Features In Brief

  • Convert to and from many audio and video compression formats and re-multiplex into various container formats, on the fly, in batch
  • Give you the control over the transcoding process and all the parameters of the transcoded files, so you can learn about, compare among and play with various codecs
  • Specific user interfaces for specific devices with device plug-ins and extensions
  • Fully standalone, no dependent on any media player, filter or codec, no registration of any components into system
  • Extensions to expand custom features and user interfaces


Typical Applications

  • Improving compression / reducing file size
  • Converting for audio/video portable devices (digital audio player, MP4 player, mobile phone, PDA, PSP, VCD/DVD player etc.)
  • Extracting audio tracks from video files
  • Ripping audio/video discs"

Virtual Dub - WINDOWS

Ogg Theora/Vorbis Support? No

Virtual Dub is an older less user-friendly transcoder for Windows, primarily authored by Avery Lee. It does not currently have support for Ogg Theora/Vorbis transcoding.

http://virtualdub.sourceforge.net/

There were modifications with some support for Ogg, grouped into this program: http://virtualdubmod.sourceforge.net/

However Virtualdub Mod does not seem to have continued development - the last news entry if for 2003.

Conclusion - As Virtual Dub is somewhat superceded by MediaCoder, it is not as important to push for Ogg support, but direct people on Windows to Media Coder instead.

ffmpegX - MAC

Ogg Theora/Vorbis Support? No

FFmpegX does not currently support Ogg. Email to ask about possibility...

FFmpegX also has trouble encoding DV files created by Final Cut Pro, a problem for most videomakers using OS X. It has a discouraging number of bugs and errors when encoding to Xvid.

http://www.ffmpegx.com

http://forum.videohelp.com/ffmpegx-general-discussion-f35.html

Quicktime Component - MAC, WINDOWS

Ogg  Theora/Vorbis Support? Yes

The release of a new quicktime component for Xiph codecs means that many applications that use Quicktime will be able to transcode to Ogg Theora/Vorbis.

http://xiph.org/quicktime/

It is now possible to export directly from iMovie or Final Cut Pro to Ogg Theora/Vorbis.

This is distributed as a component for Quicktime, it would be better to provide this as an installer package for better usability.

Test 1 29 May 2007

Setup

  • Encoding computer - Mac Powerbook 1.33 GHz PowerPC G4, 1.25 GB DDR SDRAM, OS X 10.3.9
  • Quicktime Version - 7.0.1
  • Input File - bigtime.mov (Quicktime Sorenson 3, AAC Audio)
  • 7.9 MB
  • Duration 1 minute 40 seconds
  • Dimensions 320 x 240
  • Used preset - only selected Movie to Ogg, Stereo Audio

Results

  • Failed -108

Test 2 - 29 May 2007

Setup

  • Encoding computer - Mac Powerbook 1.33 GHz PowerPC G4, 1.25 GB DDR SDRAM, OS X 10.3.9
  • Quicktime Version - 7.0.1
  • Input File - Abstractor-Billboard.mp4 (H264 / AAC audio)
  • 7.9 MB
  • Duration 1 minute 53 seconds
  • Dimensions 550 x 366
  • Used preset - only selected Movie to Ogg, Stereo Audio

Results

  • Failed -108

Contact developers with bug report.

Bug tracker here: https://trac.xiph.org/report/16

Conclusion

We recommend that the following encoders are used on each platform:

  • Linux -
  • Windows - MediaCoder to create Ogg Theora/Vorbis
  • Mac OS X - Quicktime to create Ogg Theora/Vorbis using QT Component