[FFmpeg-trac] #6570(avfilter:closed): loudnorm filter changes sample rate

FFmpeg trac at avcodec.org
Tue Aug 15 22:21:49 EEST 2017

#6570: loudnorm filter changes sample rate
             Reporter:  slhck       |                    Owner:
                 Type:  defect      |                   Status:  closed
             Priority:  normal      |                Component:  avfilter
              Version:  git-master  |               Resolution:  invalid
             Keywords:  loudnorm    |               Blocked By:
             Blocking:              |  Reproduced by developer:  0
Analyzed by developer:  0           |

Comment (by slhck):

 Okay, I understand now, thanks. Of course it makes sense to avoid
 unnecessary resampling. But seeing that multiple users are confused by
 this, and that it leads to unplayable files, there should be at least a
 sentence in the documentation saying:

 “To accurately detect true peaks, the audio stream will be upsampled to
 192 kHz.”

 One might even consider printing a warning, since no other filter that I
 know of will adjust the sample format or stream properties without
 explcitly informing the user (e.g., frame rate, pixel size, …):

 “Warning: Audio sample rate was automatically changed to 192 kHz.”

Ticket URL: <https://trac.ffmpeg.org/ticket/6570#comment:2>
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