Problem converting MOV to WebM

<html> <head> <title>your title</title> <script type="text/javascript" src="http://www.your.site.com/jwplayer/jwplayer.js"></script> </head> <body> <h2>headline</h2> <div id="container"></div> <script type="text/javascript"> jwplayer("container").setup({ file: "www.your.site.com/video.mp4", primary: "flash", height: 360, width: 480 }); </script> </body> </html>

Originally Posted by poisondeathray

I'm not sure if that's the precise reason for your observations, but they add support to the hypothesis I have , put together from dozens of different experiences over the years, where I noticed sometimes a video didn't play or had problems (not necessarily all flash based, some applications, some devices).

Basically, there are slightly different mp4 muxers and slightly different MP4 specs . Some may cause compatibility issues

The "Codec ID" actually refers to the ftyp code. Here is an excerpt of commonly used ones:

"isom" MP4 Base Media v1 [IS0 14496-12:2003]
"mp41" MP4 v1 [ISO 14496-1:ch13]
"mp42" MP4 v2 [ISO 14496-14]
"qt" Apple QuickTime (.MOV/QT)

If you want a bigger listing
http://www.ftyps.com/

"mp42" is part of mpeg-4 part 14 . It's the most compatible for the most part I've noticed across the board, but some apple devices may prefer "qt" . It adds some extensions over "isom", which I'm guessing is the reason for the compatibility issues
http://en.wikipedia.org/wiki/MPEG-4_Part_14

For example ffmpeg uses "isom" , but ffmbc uses "mp42" when muxing mp4 by default . I've noticed that the mp4's created by ffmbc seem more compatible, despite using same encoding settings. If you look up the ISO documentation, you can see the exact details.

poisondeathray - Thank-you for the info and references.

I have used a number of programs to convert my videos to MP4. Some have very limited options, others have a bewildering number of options that I don't fully understand. Nonetheless, I adjusted some of them in an effort to get a compatible MP4. Interestingly, none of those programs had an option to explicitly select either the isom or mp42 codec.

In an effort to understand and prior to posting, I did read the Wikipedia article and several other references to MP4. Most were very technical and described the different "MP4" formats and the history and standardization of their development. They were interesting but I won't pretend to understand every detail.

I was looking for something that probably doesn't exist. i.e. A specification of the exact program and/or specifications (or options) that would produce an MP4 that would be compatible on all platforms.

The whole process has been very time consuming and frustrating but in the end it was rewarding because I now have a somewhat better understanding of the issue and have found a process that seems to work. (Handbreak)

Thank-you again to both you and _Al_ for all your help. I'm always amazed at the number of wonderful people who participate in forums like this one and freely give their time and assistance to others.

Problem converting MOV to WebM

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