[FFmpeg-user] Generating bloated videos

[Bouke / edit 'B]

> On 3 Jun 2023, at 12:37, Cecil Westerhof via ffmpeg-user <ffmpeg-user at ffmpeg.org> wrote:
> 
> 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

26 is bad quality, 23 is default, stick to that. (Good quality / small size)


> 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}

Perhaps input file has compressed audio and output file uncompressed?


> 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?

The size also has to do with the encoding speed
You can gain some bits if you give FFmpeg more time.
Try ‘-preset slower’ in your line.

Bouke


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