[FFmpeg-user] Generating bloated videos

[DEF]

On Sat, 3 Jun 2023 at 11:54, Bouke / edit 'B <bouke at editb.nl> wrote:
>
>
>
> > 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?

A complete uncut console output of the command  would have given us a
change to comment on the video type and easily give directions.

>
>
> > 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
>