Improved seeking for mpc files - Page 2

snowgoon · 13 August 2006, 12:52 am

There are a couple of bugs/improvements that I should fix that could help get it approved for rb integration, eg. seeking backwards (a problem with rb core, which I can solve), and static seektable (rather than malloc, pending). Once finished I'm happy to upload a mpc.codec...

R.A.F. · 13 August 2006, 04:01 am

Okay, snowgoon. We are curiously expecting these fixes quite soon.

... and thx for the fast reply!

ilikedirt · 31 August 2006, 07:46 pm

Now in Rockbox cvs

Quote:

31 Aug 18:18: FS patch #5172 by Andrew Cupper. Musepack seeking support. Decoder should also be faster.

xmixahlx · 01 September 2006, 06:41 pm

great!

and today...

* Put Musepack output data array back in IRAM for faster DSP processing.
* Support for Musepack SV4-6 stream files. Patch by Andrew Cupper.

later

R.A.F. · 02 September 2006, 12:23 pm

Great work, snowgoon! - Works like a charm.

Lefungus · 22 September 2006, 07:53 pm

http://trac.musepack.net/trac/timeline

* Patched mppenc
* Patched libmpcdec
* Patched xmms-musepack

Credits goes to Snowgoon and R2D. Thanks !

Fast seeking will be enabled in all apps using the upcoming libmpcdec-1.2.3. mppenc-1.15w is being tested too. Already available in trunk svn for the brave souls.

Seeking will be fast, sample accurate and bit-perfect for mppenc-1.15w files.
It won't be bit-perfect for pre-1.15w files, however no audible artifacts should be heard. As it's possible to fix old files, some tool may pop-up later to convert those. Xmms make fast-seeking optional for those who want strict accuracy.

Enjoy !

[Edit] More explanations added...

Shy · 25 September 2006, 10:52 pm

notes/explanations

The next encoder release will be 1.15w. The bit stream's version number will be incremented to 7.2 (current is 7.1). The updated bitstream will be fully compatible with previous SV7 decoders/decoder libraries.

The new changes in the bitstream and the decoder library allow fast, sample and bit accurate seeking in MPC files encoded with the new encoder.

Existing MPC files, made with 1.15v and below, can also take advantage of fast seeking. The difference is that decoding accuracy after seeking, for a period of a few miliseconds and in rare cases up to a few seconds, may not be perfect (bit-accurate). A very high frequency, often unused subband may not be used during that time. The difference would most likely not be audible, and in a case where it is audible, it would pose no major issue (clicking, screeching, etc). A tool to losslessly convert existing files' bitstream (no reencoding involved) will be offered.

The release date is not set. It could take about a week or few.

Developers are welcome to test the current changes and feedback is appreciated.

01 September 2006, 06:41 pm	#24
xmixahlx Musepack developer Join Date: Nov 2004 Location: seattle, washington usa Posts: 111	great! and today... * Put Musepack output data array back in IRAM for faster DSP processing. * Support for Musepack SV4-6 stream files. Patch by Andrew Cupper. later __________________ -xmixahlx, the one they call "mike" http://xmixahlx.com -\|- http://rarewares.org

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13 August 2006, 12:52 am	#21
snowgoon Member Join Date: Mar 2006 Posts: 12	There are a couple of bugs/improvements that I should fix that could help get it approved for rb integration, eg. seeking backwards (a problem with rb core, which I can solve), and static seektable (rather than malloc, pending). Once finished I'm happy to upload a mpc.codec...

13 August 2006, 04:01 am	#22
R.A.F. Member Join Date: Feb 2005 Location: Nuremberg / Germany Posts: 7	Okay, snowgoon. We are curiously expecting these fixes quite soon. ... and thx for the fast reply!

02 September 2006, 12:23 pm	#25
R.A.F. Member Join Date: Feb 2005 Location: Nuremberg / Germany Posts: 7	Great work, snowgoon! - Works like a charm.

22 September 2006, 07:53 pm	#26
Lefungus Procrastinator Join Date: Jul 2004 Posts: 131	http://trac.musepack.net/trac/timeline * Patched mppenc * Patched libmpcdec * Patched xmms-musepack Credits goes to Snowgoon and R2D. Thanks ! Fast seeking will be enabled in all apps using the upcoming libmpcdec-1.2.3. mppenc-1.15w is being tested too. Already available in trunk svn for the brave souls. Seeking will be fast, sample accurate and bit-perfect for mppenc-1.15w files. It won't be bit-perfect for pre-1.15w files, however no audible artifacts should be heard. As it's possible to fix old files, some tool may pop-up later to convert those. Xmms make fast-seeking optional for those who want strict accuracy. Enjoy ! [Edit] More explanations added...

25 September 2006, 10:52 pm	#27
Shy Admin Join Date: Jul 2004 Posts: 372	notes/explanations The next encoder release will be 1.15w. The bit stream's version number will be incremented to 7.2 (current is 7.1). The updated bitstream will be fully compatible with previous SV7 decoders/decoder libraries. The new changes in the bitstream and the decoder library allow fast, sample and bit accurate seeking in MPC files encoded with the new encoder. Existing MPC files, made with 1.15v and below, can also take advantage of fast seeking. The difference is that decoding accuracy after seeking, for a period of a few miliseconds and in rare cases up to a few seconds, may not be perfect (bit-accurate). A very high frequency, often unused subband may not be used during that time. The difference would most likely not be audible, and in a case where it is audible, it would pose no major issue (clicking, screeching, etc). A tool to losslessly convert existing files' bitstream (no reencoding involved) will be offered. The release date is not set. It could take about a week or few. Developers are welcome to test the current changes and feedback is appreciated.