[FFmpeg-devel] [PATCH] add dumpwave filter

[Tobias Rapp]

On 12.01.2018 12:16, Дмитрий Гуменюк wrote:
> Hi
>> On 11 Jan 2018, at 09:20, Tobias Rapp <t.rapp at noa-archive.com> wrote:
>>
>> On 10.01.2018 18:18, Kyle Swanson wrote:
>>> Hi,
>>> For this to be a part of libavfilter the output needs to be more generic
>>> than the just the Soundcloud format. If we want this to be generally useful
>>> it should probably just output an array of floats between 0.0 and 1.0. The
>>> consumer of this data (JS library, or whatever) can use this in whatever
>>> way it wants.
>>
>> I agree. If the BWF Peak Envelope output which was suggested in the other thread does not match your demands and filter implementation is actually necessary I would prefer if the filter would attach the RMS value(s) as frame metadata instead of directly dumping to file. Frame metadata can then be re-
> RMS values may be counted for several frames or only for a half of a frame
>> used by other filters or dumped into file by using the existing "ametadata" filter.
>>
>> This would be similar to:
>>
>> ffmpeg -i input-file -f null -filter:a "asetnsamples=22050,astats=metadata=on,ametadata=print:file=stats-file.dat" /dev/null
> I like this idea, but won’t asetnsamples affect performance by creating fifo queue? And it may require some effort to parse long output

I added asetnsamples to define the audio frame size (interval of values 
from astats). You can reduce the number of lines printed by ametadata by 
using the "key=lavfi.astats.foo" option.

Regards,
Tobias