Creating compatible Mpeg-4 audio/video files with DivX 5, Virtualdub, Apple QuickTime6 and Mpeg4IP:

It is possible to create Mpeg-4 compliant audio/video files using DivX 5 and other useful tools, following these steps:

1. Create the audio/video file using the current version 5.02 of DivX.

   Two versions are available for Windows users: DivX basic, which is available for free and DivXPro, which offers more options, but it comes with advertisement software enclosed in the same package or if you don't want ads, you have to pay 30 Us Dollars.

   The DivXPro version has three more Mpeg-4 Tools, compared to the simple DivX codec.
   In addition to that, the pro version is able to write .mp4 files directly, but this feature is not very useful if you want to get fully mpeg-4 compliant files.

   DivX created mpeg-4 files cannot be played by Apple QuickTime6 or the Envivio plugin. Only Dicas Mpegable player and Mp4Player seem to be able to play them.

   In addition, Divx does not create audio in the AAC format. The only audio format permitted is MP3.

   It is recommended not to use the extra Mpeg-4 tools of the Pro version of DivX (leaving the three corresponding boxes unchecked) to keep the maximum compatibility of the video files with Mp4player, QuickTime6 and Envivio plugin. These options causes colored shades to appear in the picture whenever files are played by a non-Divx player.

   Thus, the DivX basic version performs well enough for our purpose.

2. Once you have an avi DivX file we can use Virtualdub (I use the current version 4.10), a powerful video editor and video capture program to edit an avi or mpeg-1 video file without the need of recompression, so that you avoid signal impairment during the editing process. Virtualdub is also capable of saving avi video and wav audio separately. To do that, load the video/audio file from open video file in the file menu. In order to save video, in the audio menu, select no audio, while in the video menu, select direct stream copy. Finally in the File menu, select save as avi typing the new video-only file name. For extracting audio, just load the original file again and choose save Wav from the file menu. You must choose a name for the wav file.

3. The next step now, is the creation of a mp4 file from the wav audio. If you have the Pro version of QuickTime6Pro, you can open the wav audio file that you have previously extracted from file\open movie, Inside the dialog box displayed, select audio file for file of type and choosing Export in the file menu again, select options to adjust bitrate mono/stereo and other settings of the mp4 aac audio file, finally press save and you should get an audio only mp4 file.

   If you don't have the Pro version of QuickTime6 which costs 29.99 Us Dollars unlike the free QuickTime6 player, you can use Faac encoder, which is available for free, to convert uncompressed pcm wav files to .aac audio.

   Another option is to use the avi2raw to extract the raw audio data, use a tool to translate the mp3 to raw PCM, then feed that raw PCM to faac.

   It has been discovered that files created with QuickTime6Pro, are not played correctly by Dicas Mpegable Player, which fails to play audio.

   If the second procedure described below is adopted, mp4 files are played smoothly by almost any of the Mpeg-4 players considered in my trial, except Philips CinePlayer.

   While converting wav to aac, make sure that Faac is set to low complexity profile and Mpeg-4 file version (not Mpeg-2) is selected. This eliminates some incompatibility problems with Quicktime6 and Envivio players.

   This is an example of Faac command-line usage:
   faac -m 4 -o lc -c 18000 -b 64 original.wav output.aac

   In the example above Faac encoder is set to create an Mpeg-4 type file header, low complexity profile, a cutoff frequency of 18000 Hz and a bitrate of 64 Kbit/s per channel aac audio file from the original wav file.

   A GUI interface to the faac encoder package is also available (this interface is not included with mpeg4ip)

   Once an .aac file is created, you can use mp4creator to insert the audio into an mp4 file. The following command line is used: mp4creator -create

   Using the Mp4UI Windows user interface for Mp4Creator is also possible.

4. Once you have an audio mp4 file you need to add the video. Just use Mp4creator to add the avi video-only Divx video track. It is very easy to use the Mp4UI Windows user interface for Mp4Creator to open the mp4 file, add the video track and optimize it, without the need of typing in the command-line commands like this:
   <mp4creator60 video.avi audio.mp4 optimize>
   The mp4 A/V file should now be playable by QuickTime6, Envivio pluin for Windows Media Player and RealOne, Dicas Mpegable player and by Mp4Player of course.

   You can use XviD encoder instead of DivX with the same result, but only versions released on September 19, 2002 or later works properly.

5. Hinting.
   To stream a file that has audio and video using a streaming server like the Darwin streaming server, you will need to hint the file.

   You can use the mp4creator's hint option. With this option, you need to specify a track number. Use the mp4info utility to get this information.

   Track	Type	Info
   1	od	Object Descriptors
   2	scene	BIFS
   201	video	MPEG-4, 166.633 secs, 262 kbps, 320x240 @ 14.16 fps
   101	audio	MPEG-4, 166.528 secs, 49 kbps, 32000 Hz

   Then use the mp4creator command line options to add the hint tracks:
   mp4creator -hint=201 file.mp4
   mp4creator -hint=101 file.mp4
   

Software Websites:

DivX video codec: www.divx.com
Virtualdub: www.virtualdub.org
QuickTime6 www.apple.com/quicktime
Mp4Creator www.mpeg4ip.net
Faac aac audio encoder www.audiocoding.com
Mp4 User Interface www.mediacruiser.de/mp4UI

Authors:

Enrico Palmeri	October 6, 2002
	revised October 7, 2002
	October 9, 2002
Bill May	edited November 18, 2002