[FFmpeg-user] Large Sized output files recieved while encoding the audio

Shubham Tiwari shubham.tiwari at observe.ai
Thu Apr 21 18:38:18 EEST 2022

Thanks for all the inputs, I have a better understanding of the problem
now. The input audio is highly compressed. While applying the filter,
ffmpeg is converting the audio based on the fileformat of the output file.
If the output file provided is wav format, the resulting file is 1536 kb/s
uncompressed cbr, hence the large file size. If the output file provided is
of mp3, mka or opus(same as the input file), then conversion of the
resulting file is taking longer.

Does ffmpeg always convert the audio file while running the filter? if not,
in what cases does it skip the conversion?

The things I tried based on the inputs:
1. ffmpeg -i call.wav -af "volume=enable='between(t,0,1)':volume=0"
-c:a copy output.mka - does not work, error: filtering and streamcopy
cannot be used together.
2. ffmpeg -i call.wav -af "volume=enable='between(t,0,1)':volume=0"
-c:a libopus output.mka - In this case conversion is happening. resulting
file size is 10mb(under expected range) but the execution time is high due
to conversion

PS: I am having discussions with the team about hiring a specialist. will
keep posted about it.


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