[CinCV TNG] [PATCH] Removed can_copy_from from file* sources

Einar R√ľnkaru einarrunkaru at gmail.com
Sat Jul 15 16:40:36 CEST 2017

On 07/15/2017 08:38 AM, igor_ubuntu wrote:
> 2017-07-14 23:48 GMT+03:00 Johannes Sixt <j6t at kdbg.org 
> <mailto:j6t at kdbg.org>>:
>     For example, when your *source is DV and you render DV*, then a DV
>     frame can be copied without decoding and encoding it (provided that
>     no changes, such as effects, are applied, of course).

Direct copy works when there is 1 video track, no effects, input and 
output have the same size, input and output media is all I-frames.

DV - DV, PNG - PNG, TIFF - TIFF work.

DV and PNG can be packed to MOV (according to current sources)

The possibility of direct copy is decided frame by frame.
> You mean the menu File->Render ? i.e. export from CV ? But cinelerra 
> does not have the option 'smart copy' as in Avidemux.

User has no control over the feature. The workaround to disable the 
feature is to apply an arbitary effect to the whole track.

> Einar says that there are noticeable differences between directly copied 
> and decoded/encoded areas.

These reports were sent a long time ago. Currently nobody wants to 
encode there video to dv or png lists. Everybody wants h264 or something 
more sophisticated - then direct copy is impossible.

The question is why it is bad to remove the feature that can be used 
only with obsoleted formats?

For me it means, that I need to have test cases and test direct copy 
after every major change. I am not interested in it. I do not see real 
usage of the feature as it is.


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