[FFmpeg-user] question about details in logging output

[Francois Visagie]

> -----Original Message-----
> From: ffmpeg-user-bounces at ffmpeg.org [mailto:ffmpeg-user-
> bounces at ffmpeg.org] On Behalf Of Michael Smithng
> Sent: 22 August 2012 17:42
> To: FFmpeg user questions and RTFMs
> Subject: [FFmpeg-user] question about details in logging output
> 
> What exactly is the 'q=' referencing in the logging output? I know this is
> quality, but I'm not finding any useful info on the web to put any kind of
key
> or legend to this value.
> 
> Thanks in advance!
> 
> Michael

It refers to the quantizer achieved for the current frame. From ffmpeg.html:
"
 . The parameter 'q' which is displayed while encoding is the current
quantizer. The value 1 indicates that a very good quality could be achieved.
The value 31 indicates the worst quality. If q=31 appears too often, it
means that the encoder cannot compress enough to meet your bitrate. You must
either increase the bitrate, decrease the frame rate or decrease the frame
size.
...
 . To have a constant quality (but a variable bitrate), use the option
'-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
quality).
"