[FFmpeg-user] Specifying input and output formats with pipes

Rhodri James rhodri at kynesim.co.uk
Tue Jul 19 19:38:15 CEST 2011

On Tue, 19 Jul 2011 17:08:03 +0100, Rhodri James <rhodri at kynesim.co.uk>  

> The docs keep leaving me thinking "-f" is forcing _input_ format,
> but that's a separate matter.  Unfortunately replacing "-f mpegts" with
> "-f mp4" fails for me.  Here's the (trimmed) log:
> ffmpeg version 0.7-rc1, Copyright (c) 2000-2011 the FFmpeg developers
> Could not write header for output file #0 (incorrect codec parameters ?)

To answer my own quesiton: Ah.  Would this be the mp4 writer not liking  
piped output because it wants to be able to seek?  IIRC mp4 has header  
fields that can't be filled in until you've done most of the work.

Rhodri James
Kynesim Ltd

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