[FFmpeg-user] problem with audio/video sync after conversion

[Christian Ebert]

* Arlo Leach on Wednesday, June 27, 2012 at 09:52:01 -0700
> Oh, yes -- I just viewed this converted video...
> 
> http://www.arlomedia.com/projects/tests/ffmpeg/sculpture_converted.php

That file is deployed with content-type: text/plain - setting it
to video/mp4 might help.

> ...on in iPad 3 running the latest iOS 5.1.1, and saw the sync
> problem there. So, not limited to Flash after all. However, I
> don't see sync problems viewing the same URL in Safari's HTML5
> playback on my Mac.

Yes, iPad seems to have problems with mp4 files - not iPhone and
iPod though - your sample file will not play on older small iOS
devices though because of the high profile.

> Here's another wrinkle that I didn't mention because I was
> focused on the Flash incompatibility. Before delivering to the
> browser, I want to pass my video files through an
> authentication script, basically like this:
> 
> <?php
> header("Content-Type: video/mp4");
> header("Content-Transfer-Encoding: Binary");
> header("Content-Length: ".filesize($filename));
> passthru("cat $filename");
> ?>
> 
> When I do this, I see the sync problem in Safari with HTML5,
> but only with the same videos that produced the sync problem in
> Flash, and only with converted videos where I changed the frame
> rate. In other words, viewing a video through this script
> produces the same behavior as viewing a video in a Flash
> player. I have no idea what this means, but I'll throw it out
> there.

The needed php incantations might vary from server to server.
Deploying video via php will put a lot of straing on your server,
don't do it unless you absolutely have to.

c
-- 
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