mp2 files: discrepancies in 1by1, mp3DirectCut and other players

[Dave_R]

Hello

MPEG1 layer2 is now widely used for DAB radio and satellite broadcasts.

I was looking for a standard way of indexing and playing radio broadcasts recorded from satellite as mp2 files. Being radio programmes they are not suitable for cutting into numerous small files.

mp3DirectCut comes close to achieving what I was looking for, by creating a cue sheet that I can use with some players, but there are some discrepancies.

I have tried various players, to see if I could find just one that works properly, but no luck.

They seem to fall into two camps:

A) Those that have playlists or cue sheets and can play individual parts of an mp2 file. But support for mp2 is faulty giving the wrong duration, warbly audio, clicks and even a gpf, depending on the characteristics of the broadcast transmission. These include mp3DirectCut, 1by1, VUPlayer, Foobar...

B) Those that play mp2 perfectly and have the correct duration but either can't play part of an mp2 file or don't support a playlist or cue sheet that can. These include WinDVD4, Windows media player 6.4, Media Player Classic 6.4.9, Media Jukebox...

It is noticeable that ones with the wrong duration are all wrong by the same amount (+1.7%), so cue sheets from mp3DirectCut work correctly with VUPlayer.

1by1 won't play any of my mp2 files properly even though it has the same settings and uses the same mpglib.dll as mp3DirectCut, which will play many mp2 files (apart from some clicks)

Media Player Classic is interesting as it is gpl, plays all my mp2 files perfectly, it gives correct duration and it can goto a time setting instantly, which the other "type B" players can't. Sadly it doesn't seem to support any suitable playlist or cue sheet format.

I speculate that "type A" programs use a backwards compatible mode of an mp3 codec and that "type B" progams use the audio part of an MPEG2 video codec.

I would like to know if I have missed something obvious, please. I would have thought what I am trying to do is not unusual, but there doesn't seem to be a working solution.

Thank you

[gaga]

You may try different decoders with 1by1.

There are "in_mad" and "in_mpg123" that play mp3 and mp2 as well.
Both work with 1by1.

in_mad:
http://www.mars.org/home/rob/proj/mpeg/mad-plugin/

in_mpg123:
http://otachan.com/in_!mpg123.html
(Translation on HA)

Use the plugin from 2006/7/11, the newer one ist fpr winamp 5 and doesn't work with 1by1.

Maybe one of these plugins work properly with your mp2-files and handles the track-positions correctly.

[Dave_R]

Hello gaga

Thank you for the suggestions. I have tried them both.

The in_!123 produces garbled audio that sounds as though it has been translated into Japanese!

in_mad.dll produces good quality audio, with no clicks, from the files that I want to play.

It is similar to the other "type A" codecs, in that the duration is wrong by the same amount as the others. But I'm not bothered about 1.7% error.

There are satellite radio stations that MAD doesn't decode correctly. e.g. France Musique on Astra 1. Satcodx says that it is 44.1kHz 256kbps, but the recorded file is detected as 48kHz. The result is warbly audio. All the "type B" players play it correctly though.

I suppose that MPEG have some way of encapsulating 44.1kHz in a 48kHz stream, and the decoder doesn't understand.

When switching from track to track within a file, or just starting with a track in the middle, 1by1 behaves a bit strangely.

First it plays a short burst of audio from the start of the file, then it starts playing a variable few seconds before correct point.

mp3DirectCut and VUPlayer both start playing at exactly the right place with no peculiar behaviour.

But at last I can connect to my hifi without worrying whether the clicks will damage my speakers. Thank you for that.