MP3 encoding quality

[TheWeebs]

I was listening to some old MP3's created with Boombox at 128 bit and following with some Timetrax MP3's created at VBR 192+. The Boombox MP3's had dramatically better sound range and stereo separation from a 128 bit stream encoded at 128 bit!

The Lame encoder in Timetrax was...well just bad! I had noticed in the past that bitrate is not everything and some encoders are just better than others but I was amazed at how good that 128 bit Boombox stuff was.

Has anyone noticed this? Any suggestions to improve the encoding quality (slider settings ect.)?

 

[src666]

Just to clarify, is Boombox an MP3 encoder? Was it XM radio content that you recorded with it?

If the Boombox files you are referring to were not XM radio content, then you need to realize that comparing an MP3 encoded from a CD to one encoded from XM will always favor the CD sourced version. The audio from XM is already compressed once (at a quality roughly equivalent to 160Kbps MP3), then uncompressed, fed into an analog sound card, re-recorded, then re-compressed into MP3. Even if everything else is perfect, you will never get better than the original 160Kbps equivalent quality from XM. But it will never be perfect, and the MP3 encoder will serve to amplify any artifacts intrduced by the XM encoder.

Of course, if you recorded the Boombox file from XM, you can ignore all that.

 

[TheWeebs]

Boombox is a internet Shoutcast stream encoder that does the same type of thing as Timetrax (but not for XM or sirius). It turns Shoutcast internet station streams to MP3's. Shoutcast streams are broadcast at various (low usually) bitrates. It would be reasonable to assume that the Shoutcast station source is a MP3 which is broadcast at 128 in this case and then encoded to MP3. XM certainly sounds much better live when listened directly from Timetrax. Live, the range and stereo separation is better than I would expect from something converted to analog from 160 bit or so (IMO). Thats why the encoding surprised me. BTW I use a Audigy 2 sound card so should not be losing quality there.

 

[dserianni]

I have made our development guys aware of this thread so that they can comment on the encoding stuff in TimeTrax.

Stay tuned (no pun intended) and we will see what they have to say.

Derek

 

[dkieffer]

Using the default Recast settings - or anything 'better', there should be virtually no difference between your 'live' listening experience to XM and your recorded MP3 listening experience. If there is, then there is something wrong with either your hardware set-up, your software settings, or the interaction between the audio encoder and your hardware.

In regard to the soundcard, the quality of the soundcard actually doesn't have a whole lot to do with the fact that the satellite audio signals are basically beat to hell and back by the time you hear audio out of your speakers. There are several options to avoid multiple digital/analog conversions and the ultimate sound quality will be effected by the quality of your equipment- but it is still compressed and converted from digital to analog and then back.

David
Time Trax