Jean-Marc Valin <jean-marc.valin at usherbrooke.ca> writes:> Quality and bit-rate are different ways of specifying exactly the same > thing. Complexity is orthogonal.That clears it up - thanks. Is this in the manual? --Randy> > Jean-Marc > > On 2010-04-03 08:28, Randy Yates wrote: >> Jean-Marc: I know you're seeing these - how about a response? >> >> --Randy >> >> Randy Yates<yates at ieee.org> writes: >> >>> If I understand these terms correctly, you cannot specify simultaneously >>> all three, e.g., high quality, low bitrate, and low complexity. >>> >>> It seems that specifying any two implies the third. For example, >>> specifying a high quality and low bitrate will necessarily require a >>> high complexity. >>> >>> Am I correct? If not, can someone please explain how these parameters >>> interact? >> > _______________________________________________ > Speex-dev mailing list > Speex-dev at xiph.org > http://lists.xiph.org/mailman/listinfo/speex-dev >-- Randy Yates % "Remember the good old 1980's, when Digital Signal Labs % things were so uncomplicated?" mailto://yates at ieee.org % 'Ticket To The Moon' http://www.digitalsignallabs.com % *Time*, Electric Light Orchestra
On 2010-04-03 22:52, Randy Yates wrote:> Jean-Marc Valin<jean-marc.valin at usherbrooke.ca> writes: > >> Quality and bit-rate are different ways of specifying exactly the same >> thing. Complexity is orthogonal. > > That clears it up - thanks. Is this in the manual?Have a look and tell me. Jean-Marc> --Randy > >> >> Jean-Marc >> >> On 2010-04-03 08:28, Randy Yates wrote: >>> Jean-Marc: I know you're seeing these - how about a response? >>> >>> --Randy >>> >>> Randy Yates<yates at ieee.org> writes: >>> >>>> If I understand these terms correctly, you cannot specify simultaneously >>>> all three, e.g., high quality, low bitrate, and low complexity. >>>> >>>> It seems that specifying any two implies the third. For example, >>>> specifying a high quality and low bitrate will necessarily require a >>>> high complexity. >>>> >>>> Am I correct? If not, can someone please explain how these parameters >>>> interact? >>> >> _______________________________________________ >> Speex-dev mailing list >> Speex-dev at xiph.org >> http://lists.xiph.org/mailman/listinfo/speex-dev >> >
Jean-Marc Valin <jean-marc.valin at usherbrooke.ca> writes:> On 2010-04-03 22:52, Randy Yates wrote: >> Jean-Marc Valin<jean-marc.valin at usherbrooke.ca> writes: >> >>> Quality and bit-rate are different ways of specifying exactly the same >>> thing. Complexity is orthogonal. >> >> That clears it up - thanks. Is this in the manual? > > Have a look and tell me.Jean-Marc, In your 1.2 Beta 3 manual, on p. 7, you discuss quality: Quality (variable) Speex is a lossy codec, which means that it achives compression at the expense of fidelity of the input speech signal. Unlike some other speech codecs, it is possible to control the tradeoff made between quality and bit-rate. The Speex encoding process is controlled most of the time by a quality parameter that ranges from 0 to 10. In constant bit-rate (CBR) operation, the quality parameter is an integer, while for variable bit-rate (VBR), the parameter is a float. The sentence "Unlike some other speech codecs, it is possible to control the tradeoff made between quality and bit-rate" implies to me that they are NOT the same thing. So, while you do discuss these terms in your manual, what you state there seems to contradict what you've stated here in this mailing list. --Randy> > Jean-Marc > >> --Randy >> >>> >>> Jean-Marc >>> >>> On 2010-04-03 08:28, Randy Yates wrote: >>>> Jean-Marc: I know you're seeing these - how about a response? >>>> >>>> --Randy >>>> >>>> Randy Yates<yates at ieee.org> writes: >>>> >>>>> If I understand these terms correctly, you cannot specify simultaneously >>>>> all three, e.g., high quality, low bitrate, and low complexity. >>>>> >>>>> It seems that specifying any two implies the third. For example, >>>>> specifying a high quality and low bitrate will necessarily require a >>>>> high complexity. >>>>> >>>>> Am I correct? If not, can someone please explain how these parameters >>>>> interact? >>>> >>> _______________________________________________ >>> Speex-dev mailing list >>> Speex-dev at xiph.org >>> http://lists.xiph.org/mailman/listinfo/speex-dev >>> >>-- Randy Yates % "Bird, on the wing, Digital Signal Labs % goes floating by mailto://yates at ieee.org % but there's a teardrop in his eye..." http://www.digitalsignallabs.com % 'One Summer Dream', *Face The Music*, ELO
Randy Yates
2010-Apr-11 14:09 UTC
[Speex-dev] What establishes "average" bitrate in Variable Bitrate (VBR) Mode?
If I specify VBR mode via speex_encoder_ctl(pSpeexEncoder, SPEEX_SET_VBR, &isTrue); then what establishes the "average" bitrate? Is it the normal bitrate command, speex_encoder_ctl(pSpeexEncoder, SPEEX_SET_BITRATE, &vbrBitrate); or the associated quality command? -- Randy Yates % "And all you had to say Digital Signal Labs % was that you were mailto://yates at ieee.org % gonna stay." http://www.digitalsignallabs.com % Getting To The Point', *Balance of Power*, ELO
Jean-Marc Valin
2010-Apr-12 04:32 UTC
[Speex-dev] What establishes "average" bitrate in Variable Bitrate (VBR) Mode?
On 2010-04-11 10:09, Randy Yates wrote:> If I specify VBR mode via > > speex_encoder_ctl(pSpeexEncoder, SPEEX_SET_VBR,&isTrue);Try: speex_encoder_ctl(pSpeexEncoder, SPEEX_SET_ABR, &desiredRate);