[clug] problem with 'lame'?

[Eyal Lebedinsky]

On 17/09/14 13:41, Bob Edwards wrote:
> On 17/09/14 10:21, Eyal Lebedinsky wrote:
>> I wonder if anyone can explain the problem I had. I now do not use this
>> method (I do ffmpeg) but still
>> want to understand why it was failing.
>
> Hi Eyal,
>
> I haven't done this sort of stuff for some years, but I notice your
> script is invoking mplayer with "-really-quiet". Maybe try running
> mplayer without "-really-quiet" and see if it is trying to tell you
> something significant about the file it is generating?

I did say that running exactly the same mplayer command but writing to a real file
creates a valid (full length) file.

But I will try your suggestion soon.

Eyal

> Cheers,
>
> Bob Edwards.
>
>>
>> I was transcoding podcasts (music programs) for many years with a simple
>> script.
>> This was the way of converting everything to pcm upfront (mplayer) then
>> encode as mp3 (lame).
>>
>> This worked fine until some time ago (first short one was Aug a year
>> ago) when it started truncating files.
>> This was consistent, with exactly the same truncation every time. Below
>> is an example.
>>
>> (1) Note the original length 2:05:04.0
>> (2) Then note how lame *starts* with a length of 1:41:21
>> (3) The result says 1:41:27.0
>> (4) Finally note that capturing the pcm shows it is not truncated.
>>
>>
>> ===== test.sh
>> prog="my_program"
>> pipe="$HOME/tmp/xxx"
>> mknod "$pipe" p
>> mplayer -really-quiet -nolirc -nojoystick -vo null -vc null -ao
>> pcm:fast:waveheader:file="$pipe" $prog.m4a &
>> lame "$pipe" $prog.mp3
>> rm "$pipe"
>> =====
>>
>>
>> ===== (1) play the original
>> $ mplayer my_program.m4a
>> MPlayer SVN-r36171-4.8.1 (C) 2000-2013 MPlayer Team
>>
>> Playing my_program.m4a.
>> libavformat version 54.63.104 (external)
>> libavformat file format detected.
>> [lavf] stream 0: audio (aac), -aid 0, -alang und
>> Clip info:
>>   major_brand: mp42
>>   minor_version: 0
>>   compatible_brands: M4A mp42isom
>>   creation_time: 2014-09-13 01:07:19
>>   encoder: Nero AAC codec / 1.5.4.0
>> Load subtitles in ./
>> ==========================================================================
>> Opening audio decoder: [ffmpeg] FFmpeg/libavcodec audio decoders
>> libavcodec version 54.92.100 (external)
>> AUDIO: 44100 Hz, 2 ch, floatle, 64.0 kbit/2.27% (ratio: 7999->352800)
>> Selected audio codec: [ffaac] afm: ffmpeg (FFmpeg AAC (MPEG-2/MPEG-4
>> Audio))
>> ==========================================================================
>> AO: [pulse] 44100Hz 2ch floatle (4 bytes per sample)
>> Video: no video
>> Starting playback...
>> A:   1.2 (01.2) of 7504.0 ( 2:05:04.0)  0.5%             <<<<<<<<<<
>> =====
>>
>> ===== (2) transcode$ sh test.sh
>> $ sh test.sh
>> LAME 3.99.5 64bits (http://lame.sf.net)
>> Using polyphase lowpass filter, transition band: 16538 Hz - 17071 Hz
>> Encoding /home/eyal/tmp/xxx to my_program.mp3
>> Encoding as 44.1 kHz j-stereo MPEG-1 Layer III (11x) 128 kbps qval=3
>>      Frame          |  CPU time/estim | REAL time/estim | play/CPU |    ETA
>>     200/233018 ( 0%)|    0:00/    5:26|    0:00/    5:28|   18.659x|
>> 5:28
>> -1:41:21-------------------------------------------------------
>> <<<<<<<<<<
>>    128.0       23.0  77.0        98.5   0.5   1.0^C
>> =====
>>
>>
>> ===== (3) play the result
>> $ mplayer my_program.mp3
>> MPlayer SVN-r36171-4.8.1 (C) 2000-2013 MPlayer Team
>>
>> Playing my_program.mp3.
>> libavformat version 54.63.104 (external)
>> Audio only file format detected.
>> Load subtitles in ./
>> ==========================================================================
>> Opening audio decoder: [mpg123] MPEG 1.0/2.0/2.5 layers I, II, III
>> AUDIO: 44100 Hz, 2 ch, s16le, 128.0 kbit/9.07% (ratio: 16000->176400)
>> Selected audio codec: [mpg123] afm: mpg123 (MPEG 1.0/2.0/2.5 layers I,
>> II, III)
>> ==========================================================================
>> AO: [pulse] 44100Hz 2ch s16le (2 bytes per sample)
>> Video: no video
>> Starting playback...
>> A:   0.4 (00.4) of 6087.0 ( 1:41:27.0)  0.3%            <<<<<<<<<<
>> =====
>>
>> ===== (4) check the pcm
>> $ mplayer -really-quiet -nolirc -nojoystick -vo null -vc null -ao
>> pcm:fast:waveheader:file=my_program.pcm my_program.m4a
>> $ mplayer my_program.pcm
>> MPlayer SVN-r36171-4.8.1 (C) 2000-2013 MPlayer Team
>>
>> Playing my_program.pcm.
>> libavformat version 54.63.104 (external)
>> Audio only file format detected.
>> Load subtitles in ./
>> ==========================================================================
>> Opening audio decoder: [pcm] Uncompressed PCM audio decoder
>> AUDIO: 44100 Hz, 2 ch, floatle, 2822.4 kbit/100.00% (ratio: 352800->352800)
>> Selected audio codec: [pcm] afm: pcm (Uncompressed PCM)
>> ==========================================================================
>> AO: [pulse] 44100Hz 2ch floatle (4 bytes per sample)
>> Video: no video
>> Starting playback...
>> A:   0.7 (00.6) of 7504.0 ( 2:05:04.0)  0.0%            <<<<<<<<<<
>> =====
>>
>

-- 
Eyal Lebedinsky (eyal at eyal.emu.id.au)