Jean-Mark sarkasm.
Jean-Markasm.
(Bonus points for providing an actual noisy WAV! ^_^)
On 30/10/2017 20:28, Jean-Marc Valin wrote:
Hi,
Before I comment on the graphics you posted to visualize the difference
between two audio signals, I'd like to ask for your help in evaluating
my JPEG encoder. I've encoded an image with JPEG and then computed the
difference with the original. I then converted the difference to sound.
You can listen to the image difference on this clip:
https://jmvalin.ca/misc_stuff/diff.wav
Can you hear how good the visual quality is? Do you think it could be
improved to make JPEG sound better? Personally, I think JPEG could do
better on my subwoofer.
Cheers,
Jean-Marc
On 10/18/2017 07:08 PM, encrupted anonymous wrote:
Good morning.
I've ran a test against MP3 format.
Code: (first convert tested audio file to 16 bit 48khz with sox.exe if
needed)
lame.exe -b 320 48khzfilein.wav -o fileout.mp3
lame --decode fileout.mp3 -o fileout.mp3.wav
opusenc.exe --bitrate 320 48khzfilein.wav fileout.opus
opusdec.exe fileout.opus fileout.opus.wav
wavdiff.exe 48khzfilein.wav fileout.mp3.wav -diff fileout.mp3.delta.wav
wavdiff.exe 48khzfilein.wav fileout.opus.wav -diff fileout.opus.delta.wav
Results: (compare two deltas with spek.exe - i've attached graphic file
from my test)
MP3 much better at 0-4 kHz, Opus little better at 12-20 kHz.
Plus I think 0-4 kHz is more important than 12-20.
Current Opus 1.2.1 is the best at 32 kbit/s for music.
But if you input 44100 Hz audio and give 96-512 kbit/s, Opus pretty badly
spends that much bitrate because of frame rate conversion.
That's all I wanted to say for now, good evening.
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Just to be clear, my goal here wasn't to make fun of anyone, but to drive the point that spectrograms should *never* be used to demonstrate quality. The only case where they can sometimes be useful is for diagnostic purposes. If you hear something and you're not sure what you're hearing exactly, then sometimes a spectrogram can help you figure out what it is. That's pretty much it. If you can't hear any artefact, who cares what the spectrogram looks like? Also, looking at the difference signal (either as a spectrogram or as actual audio) is particularly dangerous. There are many things you can do to an audio signal that are completely inaudible and yet will cause quite large differences (e.g. flip the sign or delay by X samples, but there's many more). Cheers, Jean-Marc On 10/30/2017 08:16 PM, Orestes Zoupanos wrote:> Jean-Mark sarkasm. > > Jean-Markasm. > > (Bonus points for providing an actual noisy WAV! ^_^) > > On 30/10/2017 20:28, Jean-Marc Valin wrote: >> Hi, >> >> Before I comment on the graphics you posted to visualize the difference >> between two audio signals, I'd like to ask for your help in evaluating >> my JPEG encoder. I've encoded an image with JPEG and then computed the >> difference with the original. I then converted the difference to sound. >> You can listen to the image difference on this clip: >> https://jmvalin.ca/misc_stuff/diff.wav >> >> Can you hear how good the visual quality is? Do you think it could be >> improved to make JPEG sound better? Personally, I think JPEG could do >> better on my subwoofer. >> >> Cheers, >> >> Jean-Marc >> >> On 10/18/2017 07:08 PM, encrupted anonymous wrote: >>> Good morning. >>> >>> I've ran a test against MP3 format. >>> >>> Code: (first convert tested audio file to 16 bit 48khz with sox.exe if >>> needed) >>> lame.exe -b 320 48khzfilein.wav -o fileout.mp3 >>> lame --decode fileout.mp3 -o fileout.mp3.wav >>> opusenc.exe --bitrate 320 48khzfilein.wav fileout.opus >>> opusdec.exe fileout.opus fileout.opus.wav >>> wavdiff.exe 48khzfilein.wav fileout.mp3.wav -diff fileout.mp3.delta.wav >>> wavdiff.exe 48khzfilein.wav fileout.opus.wav -diff fileout.opus.delta.wav >>> >>> Results: (compare two deltas with spek.exe - i've attached graphic file >>> from my test) >>> MP3 much better at 0-4 kHz, Opus little better at 12-20 kHz. >>> Plus I think 0-4 kHz is more important than 12-20. >>> >>> Current Opus 1.2.1 is the best at 32 kbit/s for music. >>> But if you input 44100 Hz audio and give 96-512 kbit/s, Opus pretty badly >>> spends that much bitrate because of frame rate conversion. >>> >>> That's all I wanted to say for now, good evening. >>> >>> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> >>> Без вирусов. www.avast.ru >>> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> >>> >>> >>> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> >>> >>> >>> _______________________________________________ >>> opus mailing list >>> opus at xiph.org >>> http://lists.xiph.org/mailman/listinfo/opus >>> >> _______________________________________________ >> opus mailing list >> opus at xiph.org >> http://lists.xiph.org/mailman/listinfo/opus > > > _______________________________________________ > opus mailing list > opus at xiph.org > http://lists.xiph.org/mailman/listinfo/opus >
Can such normally inaudible processing of the audio signal affect Ambisonics reproduction? -- Marc Le Lundi 30 Oct 2017 22:08:41 -0400 Jean-Marc Valin <jmvalin at jmvalin.ca> a écrit:> Just to be clear, my goal here wasn't to make fun of anyone, but to > drive the point that spectrograms should *never* be used to > demonstrate quality. The only case where they can sometimes be useful > is for diagnostic purposes. If you hear something and you're not sure > what you're hearing exactly, then sometimes a spectrogram can help > you figure out what it is. That's pretty much it. If you can't hear > any artefact, who cares what the spectrogram looks like? > > Also, looking at the difference signal (either as a spectrogram or as > actual audio) is particularly dangerous. There are many things you can > do to an audio signal that are completely inaudible and yet will cause > quite large differences (e.g. flip the sign or delay by X samples, but > there's many more). > > Cheers, > > Jean-Marc > > On 10/30/2017 08:16 PM, Orestes Zoupanos wrote: > > Jean-Mark sarkasm. > > > > Jean-Markasm. > > > > (Bonus points for providing an actual noisy WAV! ^_^) > > > > On 30/10/2017 20:28, Jean-Marc Valin wrote: > >> Hi, > >> > >> Before I comment on the graphics you posted to visualize the > >> difference between two audio signals, I'd like to ask for your > >> help in evaluating my JPEG encoder. I've encoded an image with > >> JPEG and then computed the difference with the original. I then > >> converted the difference to sound. You can listen to the image > >> difference on this clip: https://jmvalin.ca/misc_stuff/diff.wav > >> > >> Can you hear how good the visual quality is? Do you think it could > >> be improved to make JPEG sound better? Personally, I think JPEG > >> could do better on my subwoofer. > >> > >> Cheers, > >> > >> Jean-Marc > >> > >> On 10/18/2017 07:08 PM, encrupted anonymous wrote: > >>> Good morning. > >>> > >>> I've ran a test against MP3 format. > >>> > >>> Code: (first convert tested audio file to 16 bit 48khz with > >>> sox.exe if needed) > >>> lame.exe -b 320 48khzfilein.wav -o fileout.mp3 > >>> lame --decode fileout.mp3 -o fileout.mp3.wav > >>> opusenc.exe --bitrate 320 48khzfilein.wav fileout.opus > >>> opusdec.exe fileout.opus fileout.opus.wav > >>> wavdiff.exe 48khzfilein.wav fileout.mp3.wav -diff > >>> fileout.mp3.delta.wav wavdiff.exe 48khzfilein.wav > >>> fileout.opus.wav -diff fileout.opus.delta.wav > >>> > >>> Results: (compare two deltas with spek.exe - i've attached > >>> graphic file from my test) > >>> MP3 much better at 0-4 kHz, Opus little better at 12-20 kHz. > >>> Plus I think 0-4 kHz is more important than 12-20. > >>> > >>> Current Opus 1.2.1 is the best at 32 kbit/s for music. > >>> But if you input 44100 Hz audio and give 96-512 kbit/s, Opus > >>> pretty badly spends that much bitrate because of frame rate > >>> conversion. > >>> > >>> That's all I wanted to say for now, good evening. > >>> > >>> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> > >>> Без вирусов. www.avast.ru > >>> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> > >>> > >>> > >>> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> > >>> > >>> > >>> _______________________________________________ > >>> opus mailing list > >>> opus at xiph.org > >>> http://lists.xiph.org/mailman/listinfo/opus > >>> > >> _______________________________________________ > >> opus mailing list > >> opus at xiph.org > >> http://lists.xiph.org/mailman/listinfo/opus > > > > > > _______________________________________________ > > opus mailing list > > opus at xiph.org > > http://lists.xiph.org/mailman/listinfo/opus > > > _______________________________________________ > opus mailing list > opus at xiph.org > http://lists.xiph.org/mailman/listinfo/opus
Hi guys, as MP3 and Opus have very similar objectives, I think the original poster's question was a valid one: Why does Opus have more artefacts in the lower frequency ranges than MP3 has? The spontaneous suspect that lower frequency artefacts may be more noticeably than higher frequency artefacts seems plausible, also. Is it a matter of energy (which is higher for higher frequencies)? When your own ears are no longer in their best possible condition, you may try a spectrogram, just to make sure you don't miss anything. Regards, Ulrich>>> Jean-Marc Valin <jmvalin at jmvalin.ca> 31.10.17 3.09 Uhr >>>Just to be clear, my goal here wasn't to make fun of anyone, but to drive the point that spectrograms should *never* be used to demonstrate quality. The only case where they can sometimes be useful is for diagnostic purposes. If you hear something and you're not sure what you're hearing exactly, then sometimes a spectrogram can help you figure out what it is. That's pretty much it. If you can't hear any artefact, who cares what the spectrogram looks like? Also, looking at the difference signal (either as a spectrogram or as actual audio) is particularly dangerous. There are many things you can do to an audio signal that are completely inaudible and yet will cause quite large differences (e.g. flip the sign or delay by X samples, but there's many more). Cheers, Jean-Marc On 10/30/2017 08:16 PM, Orestes Zoupanos wrote:> Jean-Mark sarkasm. > > Jean-Markasm. > > (Bonus points for providing an actual noisy WAV! ^_^) > > On 30/10/2017 20:28, Jean-Marc Valin wrote: >> Hi, >> >> Before I comment on the graphics you posted to visualize the difference >> between two audio signals, I'd like to ask for your help in evaluating >> my JPEG encoder. I've encoded an image with JPEG and then computed the >> difference with the original. I then converted the difference to sound. >> You can listen to the image difference on this clip: >> https://jmvalin.ca/misc_stuff/diff.wav >> >> Can you hear how good the visual quality is? Do you think it could be >> improved to make JPEG sound better? Personally, I think JPEG could do >> better on my subwoofer. >> >> Cheers, >> >> Jean-Marc >> >> On 10/18/2017 07:08 PM, encrupted anonymous wrote: >>> Good morning. >>> >>> I've ran a test against MP3 format. >>> >>> Code: (first convert tested audio file to 16 bit 48khz with sox.exe if >>> needed) >>> lame.exe -b 320 48khzfilein.wav -o fileout.mp3 >>> lame --decode fileout.mp3 -o fileout.mp3.wav >>> opusenc.exe --bitrate 320 48khzfilein.wav fileout.opus >>> opusdec.exe fileout.opus fileout.opus.wav >>> wavdiff.exe 48khzfilein.wav fileout.mp3.wav -diff fileout.mp3.delta.wav >>> wavdiff.exe 48khzfilein.wav fileout.opus.wav -diff fileout.opus.delta.wav >>> >>> Results: (compare two deltas with spek.exe - i've attached graphic file >>> from my test) >>> MP3 much better at 0-4 kHz, Opus little better at 12-20 kHz. >>> Plus I think 0-4 kHz is more important than 12-20. >>> >>> Current Opus 1.2.1 is the best at 32 kbit/s for music. >>> But if you input 44100 Hz audio and give 96-512 kbit/s, Opus pretty badly >>> spends that much bitrate because of frame rate conversion. >>> >>> That's all I wanted to say for now, good evening. >>> >>><https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail>>>> Без вирусов. www.avast.ru >>><https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail>>>> >>> >>> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> >>> >>> >>> _______________________________________________ >>> opus mailing list >>> opus at xiph.org >>> http://lists.xiph.org/mailman/listinfo/opus >>> >> _______________________________________________ >> opus mailing list >> opus at xiph.org >> http://lists.xiph.org/mailman/listinfo/opus > > > _______________________________________________ > opus mailing list > opus at xiph.org > http://lists.xiph.org/mailma_______________________________________________opus mailing list opus at xiph.org http://lists.xiph.org/mailman/listinfo/opus