Using mp4mux with faststart option produces empty file

[Florian Zwoch]

> no, I am not sending yet EOS because this is a live content... I expected to get data into the output sink while the pipeline is running...
> I need this because I would like to be able to play the video while the pipeline is still running ?
> Is it possible ?

'faststart' will just make sure that the headers will be written to the beginning of the file. This allows to start playback while the file is partly loaded (HTTP streaming as an example). It does require a completed file though.

What you are looking for must be 'fragment-duration‘. This will write chunks of defined lengths (in time units) to the file. This file should already be playable while the pipeline continues to run. However note that some players do not support fragmented MP4 files. Afaik for example VLC does play it while QuickTime does not.