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Subject: Re: MPEG Audio format

Re: MPEG Audio format

From: Bluechip <csbluechip_at_gmail.com>
Date: 2006-01-14

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

@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 @ 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% @ Joint Stereo [Xing index: 0]
| | 83 -> 27.3% @ JS (only)
| | 221 -> 72.7% @ JS +M/S
| |
| +-- Emphasis : 304 -> 100.0% @ 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 @ 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 Sat Jan 14 07:13:16 2006


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