[FFmpeg-user] Stereoscopic hwaccel

[JackDesBwa]

> So I feel like the encoding part is the biggest bottleneck and it wouldn’t make much of a difference if the decoder and filter part are software. I don’t think the filter supports hw formats anyway, and for the second test only one of the decoders are vaapi. Setting the profile on the encoder might be what gets rid of the stereo frame packing settings, though I don’t know if the hw accelerated encoders configure those settings in the first place.

Thanks for your reply.
I also think that the encoding part is the main point to focus on, and
I am not familiar enough with this part of the cli to have caught that
I enabled hardware decoding as well (was based on an example as I was
not able to make it work by myself).
I tried to remove all custom options I could.

I tested with:
ffmpeg -i aligned/l_01.mp4 -i aligned/r_01.mp4 -filter_complex
[0][1]framepack=sbs,format=nv12|vaapi,hwupload -vaapi_device
/dev/dri/renderD128 -c:v h264_vaapi out_vaapi.mp4
It takes 6.9s wall time and produces a 40Mio output. (slower, bigger)
And there is no frame-packing information neither.

Similarly with nvenc:
ffmpeg -i aligned/l_01.mp4 -i aligned/r_01.mp4 -filter_complex
[0][1]framepack=sbs -c:v h264_nvenc out_nvenc.mp4
It takes 2.4s wall time and produces a 2.6Mio output. (faster, bigger,
still horrible compression)
And there is no frame-packing information neither.

It seems like they do not support the frame-packing although both
hardware is supposed to do (VAProfileH264StereoHigh listed by vainfo
for example)
(1) Which way could I be certain that it is not currently supported or
if there is some option to pass?
By the way, I use ffmpeg version 4.2.1 which seems to be the latest
release today.

Alternatively, I could create an accelerated regular video and then
add the frame-packing data in the video.
However, when I try this with -x264-params frame-packing=3, the video
is encoded again and I loose all the time I gained with the
acceleration.
(2) Is there a way to add the frame-packing information without a full encoding?

If my questions are too specific for this list, do not hesitate to
orient me toward better suited place.


JackDesBwa