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Converting to Opus: 44.1 kHz resampled to 48 kHz
gurkburk
post Sep 17 2012, 18:40
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So i have a bunch of regular 44100 flac files that i'de like to convert to OPUS file so i have something to listen to when i run, that's not very hard to setup following this guide.
http://www.saunalahti.fi/~cse/Opus/

What does concern me is that opusenc.exe seems to default to a samplingrate of 48000 when you feed it a raw stream (the '-' option as seen in the guide seems to do that) it's easy to see that the .opus files do indeed become converted/upsampled to 48000hz using this method.
So my question is, should i override this behavior by adding --raw-rate 44100 to the encoder?
Does it matter at all that the files get upsampled? Could it introduce noise or other unwanted side effects?

Thanks smile.gif

(yes i know that there aren't many android players yet avail for playback of opus, but the question still remains) smile.gif
Also i think this post belongs to this forums, at least it seemed like it was a good fit, but if i'm wrong please move it :\


This post has been edited by gurkburk: Sep 17 2012, 18:41
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Dynamic
post Sep 19 2012, 09:00
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Thanks again for the corrections, NullC. You know your stuff. I'll rein myself in! I guess that means that if anyone has opus (or Vorbis) files that don't playback gaplessly and glitchlessly, they should provide examples with ABX logs against the join in the lossless originals.

The sample-accurate lengths for CD-sourced material resampled to 48kHz does mean however that it doesn't matter in the slightest whether the decoder plays back at 48kHz or resamples back to the original 44.1 kHz - it's still precise.
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Brand
post Sep 19 2012, 09:55
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QUOTE (Dynamic @ Sep 19 2012, 10:00) *
I guess that means that if anyone has opus (or Vorbis) files that don't playback gaplessly and glitchlessly, they should provide examples with ABX logs against the join in the lossless originals.

I linked to an example a few posts above. You should easily hear a glitch with the transition from m1 to m2 when encoded to Opus (or MP3/AAC). Well, it helps if you listen with headphones and raise the volume.
I also posted about this same problem in the other Opus thread and I uploaded the recordings of the transition. There was an Opus build that reduced the loudness of the glitch, but it didn't eliminate it.
I haven't heard much from others, but I'd be very surprised if I'm the only one who can hear this.

EDIT2: The only time I don't get a glitch is when I decode the opus files to 44.1k wav and then play them in foobar.

This post has been edited by Brand: Sep 19 2012, 10:32
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Posts in this topic
- gurkburk   Converting to Opus: 44.1 kHz resampled to 48 kHz   Sep 17 2012, 18:40
- - [JAZ]   Opus does not natively support 44Khz. The idea is ...   Sep 17 2012, 19:03
- - LithosZA   QUOTE So my question is, should i override this be...   Sep 17 2012, 19:07
- - Kohlrabi   QUOTE (gurkburk @ Sep 17 2012, 19:40) tha...   Sep 17 2012, 19:08
- - lvqcl   QUOTE (gurkburk @ Sep 17 2012, 21:40) whe...   Sep 17 2012, 19:14
- - benski   how does the internal resampling effect gapless pl...   Sep 17 2012, 19:17
|- - Kohlrabi   QUOTE (benski @ Sep 17 2012, 20:17) how d...   Sep 17 2012, 19:28
|- - benski   QUOTE (Kohlrabi @ Sep 17 2012, 14:28) QUO...   Sep 17 2012, 20:22
|- - Brand   QUOTE (Kohlrabi @ Sep 17 2012, 20:28) Opu...   Sep 17 2012, 20:23
- - Kohlrabi   Apparently I might be wrong, it was deeply rooted ...   Sep 17 2012, 20:26
- - eahm   QUOTE (gurkburk @ Sep 17 2012, 10:40) So ...   Sep 17 2012, 21:12
- - yourlord   I believe I read in another thread that opus can...   Sep 17 2012, 21:27
- - Dynamic   To the OP's question, the resampler in Opus is...   Sep 19 2012, 01:15
|- - NullC   QUOTE (Dynamic @ Sep 18 2012, 17:15) Also...   Sep 19 2012, 05:50
|- - pdq   QUOTE (Dynamic @ Sep 18 2012, 20:15) In a...   Sep 19 2012, 15:26
- - Dynamic   Thanks again for the corrections, NullC. You know ...   Sep 19 2012, 09:00
|- - Brand   QUOTE (Dynamic @ Sep 19 2012, 10:00) I gu...   Sep 19 2012, 09:55
|- - NullC   QUOTE (Brand @ Sep 19 2012, 01:55) EDIT2:...   Sep 19 2012, 14:19
- - Brand   I can reproduce with opusenc+opusdec. In fact opus...   Sep 19 2012, 15:25
- - Case   I'm usually very sensitive to glitches, but I ...   Sep 19 2012, 16:10
- - punkrockdude   Hehe. Gurkburk, du kan inte vara något annat än sv...   Oct 8 2012, 13:25
- - C.R.Helmrich   I have a similar question as the OP. In my case th...   Jan 20 2013, 12:45
|- - nu774   I'm not an "expert" but from what I ...   Jan 20 2013, 16:35
|- - nu774   It might have not been enough explanation... ...   Jan 20 2013, 16:47
|- - C.R.Helmrich   Yes, I expected Opus to resample to 48 kHz interna...   Jan 20 2013, 22:35
|- - nu774   QUOTE (C.R.Helmrich @ Jan 21 2013, 06:35)...   Jan 21 2013, 02:19
|- - jmvalin   QUOTE (C.R.Helmrich @ Jan 20 2013, 16:35)...   Jan 21 2013, 03:55
|- - C.R.Helmrich   Thanks, guys. I'll wait for the 1.1 beta then....   Jan 21 2013, 18:40
- - IgorC   Chris, feel free to submit problematic samples for...   Jan 21 2013, 18:44
- - mzso   Why 48kHz? If the lowpass frequency is 20kHz why ...   Mar 14 2013, 15:55
|- - lvqcl   QUOTE (mzso @ Mar 14 2013, 18:55) why not...   Mar 14 2013, 16:05
- - wswartzendruber   Doesn't the CELT layer work strictly at 48 kHz...   Mar 14 2013, 21:58
- - Dynamic   I think the CELT layer in Opus (possibly not in th...   Mar 15 2013, 18:28
|- - jmvalin   QUOTE (Dynamic @ Mar 15 2013, 13:28) I th...   Mar 15 2013, 18:51
- - Brazil2   Something is still not clear to me: is the interna...   May 29 2013, 08:59
- - saratoga   No, a resampler changes the sampling rate. If the ...   May 29 2013, 14:42
- - Brazil2   That's the theory, but does it *really* behave...   May 29 2013, 16:30
|- - saratoga   QUOTE (Brazil2 @ May 29 2013, 11:30) That...   May 29 2013, 16:53
|- - greynol   QUOTE (Brazil2 @ May 29 2013, 08:30) That...   May 29 2013, 18:01
- - NullC   Thats the problem with these totally opaque closed...   May 29 2013, 19:44
|- - Banned   QUOTE (NullC @ May 29 2013, 20:44) Thats ...   Jun 2 2013, 10:29
|- - skamp   QUOTE (NullC @ May 29 2013, 20:44) Thats ...   Jun 2 2013, 10:54
- - db1989   Yes, I think we can safely deduce that sarcasm was...   Jun 2 2013, 10:58
- - Mardel   For listening test (wav file). If I resample to 44...   Sep 14 2013, 13:08
|- - bandpass   QUOTE (Mardel @ Sep 14 2013, 13:08) For l...   Sep 14 2013, 14:47
- - db1989   You tell us. You even mentioned listening tests. Q...   Sep 14 2013, 14:03
|- - Mardel   QUOTE (db1989 @ Sep 14 2013, 15:03) You t...   Sep 14 2013, 14:13
- - db1989   An assumed condition of double-blind tests is that...   Sep 14 2013, 14:19
- - Mardel   Ok. Thx!   Sep 14 2013, 18:51
- - IgorC   Here is my experience with Opus and handling of a ...   Sep 15 2013, 19:19


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