Re: making a video (animated plot)

[Pantxo]

Andreas Weber-6 wrote
> Am 04.10.19 um 18:15 schrieb Pantxo:
>> Thanks. In the mean time I will open a bug report to track the first
>> obvious
>> issues in this preliminary implementation of VideoWriter so that the
>> discussion can take place there until the code is released.
> 
> Have you seen my email from 4.10.2019 18.25 (GMT+2)?
> 
> We can make a roadmap what features should be implemented to make a
> first release. Reading/Writing RGB24 frames into various containers with
> different codecs would be IMHO the most important parts.
> 
> I think a very important part would be testing on different distros with
> ffmpeg and libav. The API changes and different makros are a real pain
> in the ass. I'm thinking of a docker directory with tests for various
> combinations ffmpeg, libav, distros and perhaps also GNU Octave 4.4.1
> 
> -- Andy

Thanks Andy,

This looks very promising. I tested the updated code, for VideoWriter only,
and it now works well for non synthetic data.
As for the roadmap, here are in IMHO the missing features that should not be
hard to have before a first realase for the VideoWriter:
* most properties should be read-only (SetAccess = "private"): ColorChannels
(codec specific), Duration, FileFormat (codec specific), FileName/Path
(fixed at object instantiation), FrameCount, Height/Width (fixed by the
first provided frame), VideoBitsPerPixel/VideoCompressionMethod/VideoFormat
(codec specific), 
* increment FrameCount and Duration after each successful call to
writeVideo,
* allow passing frames or frame arrays  directly to writeVideo, without
having to extract the "cdata" field manually,
* allow passing arbitrary image data types even if we end up converting them
internally to whatever is prefered for the chosen codec, e.g uint8 for RGB
24bits video formats.

As for the available output formats, I am no expert so in this area, I am
generally happy with whatever the default is. So we just need to make a
sensible choice of 1 or 2 widespread formats that can be read with the
default viewer for the main platforms. 

I have reproduced this post in bug #57020 so that we can carry on the
discussion in a more suitable place:

https://savannah.gnu.org/bugs/index.php?57020

Many thanks for those updates.

Pantxo



  



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