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How do I export a video with audio from separated stream? #794
Description
Overview
I want to make modification on the images only on a video. I am using pyav to load and save it.
Expected behavior
The output video must be a video with both video and audio stream.
Actual behavior
I only manage to output either an audio or a video (without audio) file.
My code look like this:
container = av.open("my_input_video.mp4")
frames = [some_transformation(img.to_ndarray(format="rgb24")) for img in container.decode(container.streams.video[0])]
output = av.open("my_output_video.mp4", "w")
audio_stream = output.add_stream("aac", 44100)
video_stream = output.add_stream("h264", 25)
video_stream.bit_rate = 1081899
video_stream.height = 1500
video_stream.width = 844
for frame in frames:
av_frame = av.VideoFrame.from_ndarray(frame, format="rgb24")
packet = video_stream.encode(av_frame)
output.mux(packet)
for audio_frame in container.decode(container.streams.audio[0]):
packet = audio_stream.encode(audio_frame)
output.mux(packet)
output.close()With the previous code, the output is a video without audio and I got the following traceback:
Traceback (most recent call last):
File "/Users/XXX/export.py", line 30, in save_reframed_video
packet = audio_stream.encode(audio_frame)
File "av/stream.pyx", line 152, in av.stream.Stream.encode
File "av/codec/context.pyx", line 466, in av.codec.context.CodecContext.encode
File "av/audio/codeccontext.pyx", line 49, in av.audio.codeccontext.AudioCodecContext._prepare_frames_for_encode
File "av/audio/fifo.pyx", line 88, in av.audio.fifo.AudioFifo.write
ValueError: Frame.pts (1934336) != expected (0); fix or set to None.
Traceback (most recent call last):
File "av/container/output.pyx", line 25, in av.container.output.close_output
TypeError: 'NoneType' object is not iterable
Exception ignored in: 'av.container.output.OutputContainer.__dealloc__'
Traceback (most recent call last):
File "av/container/output.pyx", line 25, in av.container.output.close_output
TypeError: 'NoneType' object is not iterable
Process finished with exit code 1
Now I've tried to change the order of stream (starting with the audio) and I only got an audio file without video. In this order there is no error displayed, and I can see 2 streams in the output when I'm in debug mode.
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