|
Rockbox mail archiveSubject: Re: MPEG Audio formatRe: MPEG Audio format
From: Bluechip <csbluechip_at_gmail.com>
Date: Sat, 14 Jan 2006 06:12:02 +0000 Whoops ...hit send a bit quick Nice of LAME to not update the frame counter when it completes. Meant to append this: D:\x>c:lame themic~1.wav LAME version 3.96.1 (http://lame.sourceforge.net/) CPU features: MMX (ASM used), 3DNow! (ASM used) Using polyphase lowpass filter, transition band: 10758 Hz - 11025 Hz Encoding The Microsoft Sound.wav to The Microsoft Sound.wav.mp3 Encoding as 22.05 kHz 64 kbps j-stereo MPEG-2 Layer III (11x) qval=3 Frame | CPU time/estim | REAL time/estim | play/CPU | ETA 300/302 (99%)| 0:01/ 0:01| 0:02/ 0:02| 4.0816x| 0:00 average: 64.0 kbps LR: 83 (27.30%) MS: 221 (72.70%) Writing LAME Tag...done ReplayGain: -2.6dB _at_0x000000D0+0.0, 63529 - 304 MPEG audio frames | ,-- | | MPEG Version : MPEG Version 2 (ISO/IEC 13818-3) | | MPEG Layer : Layer III | | Samplerate : 22050 Hz | | Bitrate : CBR _at_ 64 KbpS | | Samples/Frame : 576 | | Frame Time : 26.122449 mS | | | | Frame Count : 304 -> 100.0% (of ALL frames) | | Frame Time : 0:00:07.941 | `-v | | (%'s below are for this block only) | | | +-- Channels : 304 -> 100.0% _at_ Joint Stereo [Xing index: 0] | | 83 -> 27.3% _at_ JS (only) | | 221 -> 72.7% _at_ JS +M/S | | | +-- Emphasis : 304 -> 100.0% _at_ No Emphasis | | | | --- Enabled ---- -+- --- Disabled --- | +-- Original : 304 -> 100.0% | 0 -> 0.0% | +-- Copyright : 0 -> 0.0% | 304 -> 100.0% | +-- Private : 0 -> 0.0% | 304 -> 100.0% | | | | +-- Protected : 0 -> 0.0% | 304 -> 100.0% | +-- Padding : 297 -> 97.7% | 7 -> 2.3% | | ^ | `-- Bitrate : CBR _at_ 64 KbpS `--------------------------------------------------------------------- >>I just ran lame with no options on the first file I found and got the >>following output: >>--------------- >>LAME version 3.96.1 (http://lame.sourceforge.net/) >>CPU features: MMX (ASM used), SSE, SSE2 >>Using polyphase lowpass filter, transition band: 17249 Hz - 17782 Hz >>Encoding concat.wav to concat.mp3 >>Encoding as 44.1 kHz 128 kbps j-stereo MPEG-1 Layer III (11x) qval=3 >> Frame | CPU time/estim | REAL time/estim | play/CPU | ETA >> 2379/2381 (100%)| 0:09/ 0:09| 0:10/ 0:10| 6.2245x| 0:00 >>average: 128.0 kbps LR: 849 (35.64%) MS: 1533 (64.36%) >> >>Writing LAME Tag...done >>ReplayGain: -0.8dB >>----------------- >>As you can see on the line starting with "average" this particular sample >>used joint-stereo on 64% of the frames. >> >>If you don't have lame installed or can't find a track that produces both >>kind of frames, I can easily put this file somewhere. > >LR: 849 (35.64%) MS: 1533 (64.36%) > >Means that 64.36% of the Joint Stereo frames utilise the "+MS" thing ...I >have no idea what it is, but I do know it is a Joint Stereo enhancement >held in the MODE bits of the header - which are only relevant if the >CHANNEL bits are set to Joint Stereo. There is also a "+IS" (intentsity >stereo) and the combo "+M/S +IS" > >BC > > >>David >> >> > >> > >When it comes to sample rate, layer and version switching, I think you're >> > >reasonably safe, though it is probably legal. Stereo mode I think you >>will >> > >find encoders may switch from frame to frame. >> > >> > Is anyone in a position to send me an example file please? Or seond-best, >> > name an encoder with a required set of options. >> > >> > Difficult to test my app without test data - and quite a chore to >> > manufacture such a file by hand. (...and that bit of the app is not yet >> > written) >> > >> > BC >> > >> > Received on 2006-01-14 Page template was last modified "Tue Sep 7 00:00:02 2021" The Rockbox Crew -- Privacy Policy |