[PD] [GEM] output gemwin to video file workaround using ffmpeg on macos

[Johnny Mauser]

For me on OSX syphon + syphon recorder works best.

Antoine Villeret <antoine.villeret at gmail.com> schrieb am Fr., 29. Mai 2020,
10:54:

> Hi,
>
> what about using a screen casting tool ? they are usually made for gaming
> and thus optimized for real time performance.
> On macos, quicktime player is a pretty simple solution for that.
> The only drawback I saw is that you're stuck with the rendering window
> size since the tool grab a part of the screen, you can't render at a bigger
> resolution than the display's one.
>
> My 2 cents
>
> A
>
> Le ven. 29 mai 2020 à 10:05, cyrille henry <ch at chnry.net> a écrit :
>
>> hello,
>> The open GL rendering is made in the GPU. grabbing the images by the CPU
>> in order to compress them and to record them in the HDD is a slow operation.
>> I think some software are able to compress the image in the GPU in order
>> to grab a smaller file, but Gem don't.
>> So, there is not a lot's of solution, and you already found them.
>>
>> I use pix_record when I need a correct quality of a small video. I use
>> mjpa with good result.
>>
>> When I need better quality, I use pix_writer. Usually this can not be
>> made in real time. I.E : I create a process that render exactly what I
>> want, without human interaction. (For live performance, I record all human
>> interaction in tables or texts file during the performance, then I use this
>> data to play again the same performance)
>> Then, It's possible to record both image annd sound in the same time.
>> Even if pd will not be sync with real (external) time, the time inside pd
>> will still stay consistent. I.E : even if there are lot's of audio dropout
>> and the recording fps is 1/2 of the real fps, pd will still record a
>> perfect audio file that will be perfectly sync with the video. You just
>> need to start the audio and video recording with the same "bang".
>>
>>
>> cheers
>> Cyrille
>>
>> Le 28/05/2020 à 22:33, ffdd cchh a écrit :
>> > Hi everyone,
>> >
>> > Is it possible to grab the OpenGL stream with ffmpeg and save to a
>> video file? If so, could anyone point in the right direction as to how to
>> capture the stream opened by Gem?
>> >
>> > The reason I ask this is that I am looking for ways to render video
>> frames to a file and I have not managed a good result using neither
>> [pix_record] nor [pix_writer].
>> >
>> > With [pix_record] I have systematically tried all codecs and
>> colorspaces and I had no luck.
>> >
>> > With [pix_writer], I did manage high quality frames with the correct
>> colorspace which I then concatenated into a video (with ffmpeg). The
>> drawback I have with [pix_writer] is the time it takes to write, which
>> really complicates audio and video synching.
>> >
>> > Thanks!!
>> >
>> > Fede
>> > --
>> > fdch.github.io <http://fdch.github.io>
>> >
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