[FFmpeg-user] Generating bloated videos

Cecil Westerhof Cecil at decebal.nl
Sat Jun 3 13:37:04 EEST 2023

I am not knowledgeable in the fine points of video processing, so it
is possible that I ask for something that is not realistic.

Sometimes the output stream becomes bigger as the input stream and I
find this strange.
In the past I used:
    -vcodec libx264 -crf 26

and this gave videos that I saw no difference in and where often
1/14th of the original size.

But sometimes they become bigger.

For example I have an input file of 117.5 MB.
If I use:
    ffmpeg -i ${inputfile}           \
           -vcodec libx264           \
           -crf 28                   \
           -af "volume=${volumeCmd}" \
           -y ${outputfile}

the output file becomes 129.4 MB.

Well that could be because of the audio filter.
But when I do:
    ffmpeg -i ${inputfile}           \
           -vcodec copy              \
           -af "volume=${volumeCmd}" \
           -y ${outputfile}

the output file becomes 110.7 MB. Almost 2/13 smaller.

This seems strange to me, or am I missing something?

Cecil Westerhof
Senior Software Engineer
LinkedIn: http://www.linkedin.com/in/cecilwesterhof

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