[theora] Ogv file only plays in VLC / Can't be used by most tools.

[Mark Pope]

Thank you all for your helpful responses.

I got the latest ffmepg (from http://ffmpeg.arrozcru.org/autobuilds/) and it converts my file to mpeg fine. This gives me the workaround I needed. Thanks!


I used VLC to convert to 264 format and mpeg4 format. (To do so, choose 'Media -> Convert / Save'.)  Perhaps it uses a different decoder for playback than conversion?

Also my usage case is more complicated than encoding bitmaps, I was just using that as an intermediate step.

Thanks again,
Mark.

-----Original Message-----
From: xiphmont at gmail.com [mailto:xiphmont at gmail.com] On Behalf Of xiphmont at xiph.org
Sent: Friday, April 30, 2010 2:57 PM
To: Mark Pope
Subject: Re: [theora] Ogv file only plays in VLC / Can't be used by most tools.

> I downloaded the Theora encoder sample (ver 1.1.1), modified it to encode a
> sequence of bitmaps, and created an OGV file.
>
> The OGV file plays fine in the latest VLC (1.0.5), but I can't do much else
> with it:

Unfortunately, the summary to all the problems you're having below is
probably 'ffmpeg'...

> I tried uploading to YouTube, and the video just comes out really corrupt:
> http://www.youtube.com/watch?v=sHaMG6mcWu0

YouTube uses an older, buggy version of ffmpeg to handle video, and it
can't read Theora properly.  Until recently, ffmpeg just treated
Theora as if it was still VP3, so it can't actually handle real Theora
files.

This was just fixed a few months ago, but Google/Youtube are still
using the broken version.

> I tried using ffmpeg to convert to another format, but it gives errors
> (listed below).

Probably the same problem unless you're sure you have a recent build.

> I tried using MEncoder264 and it failed too. The log is below the FFmpeg
> log. A potentially useful line of the log is: "Theora header parsing failed:
> -23"

THis also uses ffmpeg to decode theora.

> I also tried using VLC to convert, but it created a zero sized file too.

That's more interesting.  What did you try to convert it to?

> It seems like the OGV file is bad in some way, but VLC is somehow 'luckily'
> able to play it.

You could send a snippet of the file and I'll inspect it.  it's
possible something did go wrong with the modifications to
encoder_example.

BTW, png2theora will make an OGV out of a directory of .PNG files.

Monty