[vlc-devel] How to resize video when render to custom are in memory

Łukasz Korbel korbel85 at gmail.com
Wed May 23 22:30:25 CEST 2012

Thank you. This should push me further.

2012/5/23 Rémi Denis-Courmont <remi at remlab.net>:
> Le mercredi 23 mai 2012 22:46:03 Łukasz Korbel, vous avez écrit :
>> Im using vlc to render video frames directly to some memory buffer.
>> I need to be able to resize video while media is playing. Function
>> libvlc_video_set_scale doesn't work for this (i assume its working
>> when vlc is connected to os native window).
> Setting the scale makes absolutely no sense when using custom buffers. The
> scale is intrinsically fixed to the ratio of the source format resolution to
> the output format resolution.
> If you want to preserve the input resolution, or more generally select the
> output resolution based on the input resolution, you need
> libvlc_video_set_format_callbacks() instead of libvlc_video_set_format().
>> The only other function I've found that allows resizing is
>> libvlc_video_set_format, which is used when initializing decoding. The
>> problem is it will take no effect until media is playing so its not
>> enough (It "works" when i stop, set format and play but its really
>> stupid;))
> The video output pipeline must be reset to change the output buffers. Also
> filters will need to be reinitialized, if only the scaling filter.
> A crash would be almos certain if changing format on the fly was permitted.
>> In the end i want to add that connecting to window of any window
>> system is not an option for me.
>> Please give me some clues. Maybe there
>> is another way or this is limitation of API. If the second then maybe
>> it can be improved?
> Basically, you need to write your own video output plugin.
> --
> Rémi Denis-Courmont
> http://www.remlab.net/
> http://fi.linkedin.com/in/remidenis
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