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IDProjectCategoryView StatusLast Update
0002623gnunet-gtkgnunet-fs-gtkpublic2017-06-17 09:59
ReporterLRN Assigned To 
Status confirmedResolutionopen 
Product VersionGit master 
Summary0002623: Audio previews in KBlocks
DescriptionBratao proposes to use Opus to encode small bits (up to 10 seconds?) of audio at extremely low bitrate, and embed these as previews in KBlocks.
TagsNo tags attached.



2012-11-06 20:28

developer   ~0006534

Things to consider:

1) How to choose which piece of audio to encode? The simplest way is to take the audio, trim silence at the beginning, encode first N seconds. More complex technique - analyze the audio, find the juiciest piece of it (what's the definition of "juicy", and which metric should be used?) and encode N seconds of that.

2) How to choose N? Size restriction on KBlocks is somewhat floating, and it is metadata serializer that eventually gets to keep a piece of metadata or throw it away. The most optimal way would be, IMO, to first serialize all metadata normally, then see how much space is left and encode just enough audio to fill it, and then either serialize everything again (with a preview), or maybe just concatenate audio to the metadata?

3) Who will do all that? Metadata is normally extracted by LE, but logic described above doesn't look like it's suitable for LE (i.e. metadata serializer interaction). Can Opus-encoded file be cut at arbitrary position without distorting audio? I think it should be, since it has ultra-low delay...


2012-11-06 20:40

reporter   ~0006535

Last edited: 2012-11-06 20:40

What if we use a "Fixed" size. Something like 30K ? This could simplify the "silence" detector as like you said, silence compress well.


2012-11-06 21:00

developer   ~0006536

I don't see how that simplifies silence detector.

I expect silence to compress well, but how well - that remains to be measured.

Christian Grothoff

2012-11-06 21:04

manager   ~0006537

Before this can be implemented in gnunet-fs-gtk, we need a plugin doing the actual opus work in GNU libextractor.

Issue History

Date Modified Username Field Change
2012-11-06 20:21 LRN New Issue
2012-11-06 20:28 LRN Note Added: 0006534
2012-11-06 20:40 bratao Note Added: 0006535
2012-11-06 20:40 bratao Note Edited: 0006535
2012-11-06 21:00 LRN Note Added: 0006536
2012-11-06 21:03 Christian Grothoff Project GNUnet => gnunet-gtk
2012-11-06 21:03 Christian Grothoff Category file-sharing service => General
2012-11-06 21:03 Christian Grothoff Category General => gnunet-fs-gtk
2012-11-06 21:04 Christian Grothoff Note Added: 0006537
2013-09-15 21:48 Christian Grothoff Status new => confirmed
2013-09-15 21:48 Christian Grothoff Product Version => Git master
2013-09-15 21:48 Christian Grothoff Target Version => 0.11.0pre66
2014-04-11 15:18 Christian Grothoff Target Version 0.11.0pre66 => 0.11.0
2015-03-21 00:41 Christian Grothoff Target Version 0.11.0 =>