[FFmpeg-user] Converted file size is bigger than source.

Reindl Harald h.reindl at thelounge.net
Fri May 13 17:03:12 CEST 2011

Am 13.05.2011 16:35, schrieb Anil Jangam:
> Team,
> We have observed a scenario in which the size of the output transcoded file (~500kb) is greater than the size of the original video file (~140kb). Upon checking with media info tool (and with ffmpeg), we found that the video codec is h263 and audio codec used is amr (see below).
> Duration: 00:00:13.20, start: 0.000000, bitrate: 86 kb/s
> Stream #0.0(und): Video: h263, yuv420p, 176x144 [PAR 12:11 DAR 4:3], 29.97 tbr, 30k tbn, 29.97 tbc
> Stream #0.1(und): Audio: libopencore_amrnb, 8000 Hz, mono, s16
> Upon checking the properties of the output file, it shows that video codec is 'mpeg4_sp' and audio codec is 'aac_lc'.
> I am not sure if 'mpeg4_sp' is a low compression ratio codec as compare to the 'h263'. In that case, conversion of 'h263' coded video into 'mpeg4_sp' codec video will obviously result in the higher size of the transcoded output.
> Can you please confirm this?

Depends on codec and bitrates

86 kb/s input file is a very low bitrate
if your output is higher there is no other option as getting bigger
with H264/AAC-Audio and a low bitrate it should get even smaller

but anyways: post your full cli-call, without it is impossible to say anything away from guessing

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