Re: Why does flattening a movie (composed of same type segments) create multiple video tracks?

Subject: Re: Why does flattening a movie (composed of same type segments) create multiple video tracks?

From: Erik Hedenström <email@hidden>

Date: Sun, 6 Aug 2006 09:05:13 +0200

Delivered-to: email@hidden

Sorry Alex, I should have been a bit more clear.

The input clips are each composed of a video track and an audio track. In total there are 5 movies to be merged. In the first and last movie the audio track comes before the video track, In movies 2,3, and 4 the video track comes before the video track.

When the 5 movies are merged using the insertSegment method and the saved via flatten the resulting movie contains :

- 1 video track with the video from movies 1and 5

- 1 audio track of all the movies combined.

- 1 video track with the video from movies 2,3, and 4

If the 5 input movies have the video and audio track in the same order the merged and flattened movie contains only 1 video track and 1 audio track.

What seems a bit strange to me is that the video tracks don't get merged but the audio tracks do.

-Erik

On 5 aug 2006, at 14.41, Alex Shaykevich wrote:

Could you explain this a bit more? Aren't tracks automatically ordered since they have a timestamp? I'm not following.

--Alex

Erik Hedenström <email@hidden> wrote:
I think I've figured out why the export created multiple video tracks.

It seems that it depends on the order of the tracks in the input clips. Once all the clips had the tracks in the same order (first video, then audio) the flattened file only had two tracks.

--Erik

On 5 aug 2006, at 09.05, Alex Shaykevich wrote:

Oooh, I see the problem. I didn't know that was the case with exporter, though I can't say I'm surprised. The JNI portion of it has never seemed to me to be too robust. Probably worth flagging this as a bug for Apple.

Perhaps you can try a hack on it, by saving only the resource file for the movie, then spawning a separate JVM process(via exec()) to do the final export. I'm not sure, but I think I remember reading that the ffmpeg folks were working on QT resource file support, but maybe it's just wishful thinking on my part.

Sorry I can't be of actual help.

Good luck.

--Alex

Erik Hedenström <email@hidden> wrote:

Thanks for the tip Alex. I've already tried this and it does create a single video track but the problem is that the exporter does not play nice in a multithreaded scenario. If i start 2 exporters at the same time, each in it's own thread, the first exporter will block the second one until it's done. Any thoughts on why this happens and how to do exports in parallel would be greatly appreciated.

Thank, Erik

On 5 aug 2006, at 04.49, Alex Shaykevich wrote:

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References:
	>Re: Why does flattening a movie (composed of same type segments) create multiple video tracks? (From: Alex Shaykevich <email@hidden>)