How do I write to webp?

[FredHappyface]

Thanks for the awesome project, I was kindly informed about this when investigating performance when converting tgs/lottie using python-rlottie + pillow

Overview

I've been able to use pyav to write to 'gif' and 'apng' sucessfully, however, I cannot work out if webp is supported, the errors suggest not but I just wanted to clarify as I'm pretty new to using this library

from typing import cast 

import av
import numpy as np
from av.video.stream import VideoStream
from rlottie_python import LottieAnimation

anim = LottieAnimation.from_tgs("sample.tgs")

frames = anim.lottie_animation_get_totalframe()
fps = anim.lottie_animation_get_framerate()
width, height = anim.lottie_animation_get_size()
options = {
    "loop": "0"
}

with av.open(f"sample.webp", "w", format="webp") as output:
    out_stream = output.add_stream("webp", rate=fps, options=options)
    out_stream = cast(VideoStream, out_stream)
    out_stream.width = width
    out_stream.height = height
    out_stream.pix_fmt = "rgb8"

    for i in range(frames):
        buffer = anim.lottie_animation_render(i)
        frame = np.frombuffer(buffer, dtype=np.uint8).reshape((width, height, 4))
        av_frame = av.VideoFrame.from_ndarray(frame, format="bgra")
        output.mux(out_stream.encode(av_frame))
    output.mux(out_stream.encode())

anim.lottie_animation_destroy()

Expected behavior

A list of supported codecs somewhere would be really useful as I've not been able to find these

Actual behavior

'webp' codec is not available, same behaviour when using 'libwebp'

Traceback:

    out_stream = output.add_stream("webp", rate=fps, options=options)
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "av\\container\\output.pyx", line 67, in av.container.output.OutputContainer.add_stream  
  File "av\\codec\\codec.pyx", line 185, in av.codec.codec.Codec.__cinit__
  File "av\\codec\\codec.pyx", line 194, in av.codec.codec.Codec._init
av.codec.codec.UnknownCodecError: webp

Investigation

Tried searching the docs for supported codecs, tried looking through the code and searching the repo for 'gif' 'webp' etc and have found no results. Searching webp and ffmpeg suggests it is supported

Research

I have done the following:

• [x] Checked the PyAV documentation
• [x] Searched on Google
• [x] Searched on Stack Overflow
• [x] Looked through old GitHub issues
• [ ] Asked on PyAV Gitter
• [ ] ... and waited 72 hours for a response.

Additional context

{{ Add any other context about the problem here. }}

[WyattBlue]

Right now, we don't currently build wheels with webp support.

[laggykiller]

@WyattBlue Why not though? I have successfully built ffmpeg with libwebp then build pyav with libwebp-enabled ffmpeg without problem.

My fork of pyav-ffmpeg that can build libwebp-enabled ffmpeg: https://github.com/laggykiller/pyav-ffmpeg/tree/enable-libwebp

The built pyav wheels could be downloaded from here: https://github.com/laggykiller/PyAV/releases/tag/6.1.0-libwebp-1

I can open PR for this: https://github.com/PyAV-Org/pyav-ffmpeg/compare/main...laggykiller:pyav-ffmpeg:enable-libwebp

If you don't want to enable libwebp in pyav, I can just maintain my fork and upload to pypi.

[WyattBlue]

@laggykiller You should make a PR for https://github.com/PyAV-Org/pyav-ffmpeg

[laggykiller]

@WyattBlue Opened PR https://github.com/PyAV-Org/pyav-ffmpeg/pull/96

[jlaine]

I have merged @laggykiller, once CI completes I will point PyAV's build to the new binaries.