Hello,
I had a set of new files I edited in 16bit/48000 which were lossless .WAV’s I made to add as new audio for a DVD project.
When it came to muxing the video and audio it wouldn’t work with .WAV so I needed to convert to .MP2 (as the original audio was .mpa I knew .MP2 should work).
As I usually only ever work with lossless audio files, and don’t deal with much video or lossy files I was wondering how the quality of .MP2 compares to WAV or MP3?
I converted my original PCM WAV 16bit/48000 files by loading into Audacity and simply exporting as MP2 16bit/48000 at 384kbps.
Is 384kbps for an .MP2 about the same audio quality as an MP3 would be at 384kbps?, or do things work differently?
I imagine converting lossless WAV to 384kbps MP2 would not have any audible quality loss?
Thanks
WAV is a “lossless” format whereas MP2 and MP3 are lossy formats. Encoding to a lossy format always discards some of the audio information, whereas encoding to a lossless format does not. If the bit-rate of the lossy format is high enough then the losses will not normally be noticeable, though please note that the “loss” is permanent and not reversible. It is highly recommended that editing is done using “lossless” formats for the source material as the losses for lossy formats will accumulate, much in the same way as making a photocopy of a photocopy reduces the image quality until eventually it becomes a complete mess.
The highest bit rate for a standard MP3 is 320 kbps.
The highest bit rate for a standard MP2 is 384 kbps.
In both cases the losses are likely to be insignificant (no audible loss).
MP3 (more correctly “MPEG 1 Layer 3”) is more complex that MP2 (more correctly “MPEG 1 Layer 2”) and was designed to give better audio quality at lower bit-rates. This an MP3 at 128 kbps is likely to sound better than an MP2 at 128 kbps. Above about 256 kbps either will produce “near transparency” (very little audible loss).
Thanks Steve,
Yes I already know all you mentioned, but didn’t know how .MP2 bitrates compared with .MP3 bitrates, I have never worked with .MP2 before.
Thanks for the info.
I had a set of new files I edited in 16bit/48000 which were lossless .WAV’s I made to add as new audio for a DVD project. When it came to muxing the video and audio it wouldn’t work with .WAV
DVDs can use LPCM which is equivalent to WAV.* Your video editor/DVD authoring software should support LPCM, and most related video software also supports Dolby AC3.
AC3 is lossy, but some of the best sounding music I’ve heard coming from my stereo are concert DVDs with 5.1 channel Dolby AC3!
The biggest issue with LPCM is that it can take-up lots of space on the DVD.
If you live in the U.S., note that NTSC DVD players are not required to support MPEG-2 audio. The only DVD I’ve ever seen with MP2 audio is one I accidentally made myself! 
However, All PAL players can play MP2 so if you live in a PAL country you’ll be OK.
All DVD players anywhere in the world are required to support LPCM and AC3.
From [u]Wikipedia[/u]:
In countries using the PAL system standard DVD-Video releases must contain at least one audio track using the PCM, MP2, or AC-3 format, and all standard PAL players must support all three of these formats. A similar standard exists in countries using the NTSC system, though with no requirement mandating the use of or support for the MP2 format.
***** Normal WAV files are LPCM (Linear Pulse Code Modulation) but they are always just called PCM.
Hi,
When I was muxing the video with my new PCM WAV audio it kept erroring because of high bitrate, so as the original audio was .mpa (MP2) I knew it should work once I converted to MP2.
I usually never work with lossy files, but I just couldn’t get the lossless files to mux…
Thanks