converting audio to .mpa for multiplexing

[mattwb1]

Hi,
I am looking for anything that will convert an audio file to .mpa.
I encode from BetaSP tapes to mpeg2 through optibase encoding card and software. I need to make sure that all the video levels are constant. It was decided to make sure that the rms level of the audio measures 0.25 (to match the other audio media we use). I can encode in program, system or transport mpg's and also as mpa and mpv together or seperately. The Optibase software has a multiplexing ability but only with mpv and mpa files.
I currently use Goldwave to alter the rms level, but this will not save files as mpa so I have been saving as wav. The nearest I can get to a complete mpg is to multiplex through TMPGEnc as seen on this site. Unfortunately this appears to change the codec and it will not play on some of our players. The computers with Optibase hardware decoding cards are fine, but we also use ge-force cards which don't work. They kind of play the audio - very jumpy, but will not play the video. I can't change the codecs on these machines as they are in the field. They use an embedded windows media player 6.4.
Back to the point, does anyone know of a wav, mp3, mp2 etc (I can convert to most of these easily) to mpa converter.

Cheers Matt

[Dragonsf]

First a question: you want to normalize an audio file to +0.25 dB RMS or -0.25 dB ?
I always thought that mp3 and mpa qre quite the same ? (mpa=mpeg audio, mpv = mpeg video).If so, you can use CoolEdit with mp3-Plug-In as Audio editor. It works for me (on mpa anayway).I'm just doing the same (extracting the audio, process it and remltiplex it)

[vitualis]

The MPEG audio as used on VCDs and SVCDs is MPEG-1 Layer 2 audio.

MP3 is MPEG-1 Layer 3.

You cannot use MP3 audio on VCDs or SVCDs.

Most MPEG-1 video encoders will also encode an uncompressed WAV file to MPEG-1 Layer 2 audio (@ 224 kbit/s stereo for VCD). This includes TMPGEnc, Panasonic, LSX and Xing.

TMPGEnc's native audio encoder is generally considered to be poor, but luckily, this is recognised and you can use a free MP2 encoder plug-in with it. tooLame is a good choice.

BTW, the extension of .mpa is irrelevant. You could rename the extension .mp2, .m1a, .mpa, .zzz, etc. It's what in the file that counts.

Regards.

[mattwb1]

Hi Guys,
Thanks for the replies. I have just tried renaming the file extension from mp2 to mpa. This seems to be working. Now for some more testing!
Thanks for the help. :P
Cheers Matt

[Dragonsf]

OK vitualis, you're with mp3 (even tmpgenc lets you choose an mp3 file). But one question remains: After editing a wavefile and converting ithe wave to mp2 with wav2mp, I notice, that the movie gets out of sync in two ways:
- at the beginning of the mp2 a silence of 0.010 sec is added
- over the time frames are dropped (after 60 min more than 20 frames)
The result is anoying, the sync is compeletly gone aftzer 30 min.
Question: why the droped frames and how comes, that video and audio got the same lenght after remux ?
Video is in SVCD PAL with 1600 VBR)

[vitualis]

Don't know... maybe someone else can answer this. Have you tried using another MP2 audio encoder?

Regards.