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Topic: ADPCM vs. MP3 (Read 9659 times) previous topic - next topic
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ADPCM vs. MP3

Hi folks. I was wondering how I can make an informed decision as to what codec would be more efficient: mp3 of ADPCM ... ? I only found one thread here directly dedicated to this issue, and the recommendation was to "just listen and decide for yourself" ...

... but I have "bad" ears, so I would rather like to make a "brain" decision ... so if someone could help me with this ? Thanxxx

ADPCM vs. MP3

Reply #1 –
Create sine sweep from 1 to 22000 kHz. Encode it to ADPCM 352 kbps and mp3 320 kbps. Compare both.

ADPCM vs. MP3

Reply #2 –
What sort of files are you going to be compressing?  What's your use?

ADPCM vs. MP3

Reply #3 –
thanks for showing up guys ...

@tahnru: it would be voice audio. But actually my question is more of a theoretical nature (I'm trying to better understand ...)

@lvqcl: how can I create a sine sweep? And once I have the sine waveforms, how would you expect me to compare them ... checking which curve has a greater standard deviation ?

ADPCM vs. MP3

Reply #4 –
Quote
how can I create a sine sweep?

Audacity 1.3.5 is free and have this option: Generate -> Chirp. Set amplitude to 0.5, samplerate - from 1 to 22000, interpolation = linear.

Quote
how would you expect me to compare them

Just listen how ADPCM encodes sine waves with samplerates > 6kHz.
This shouldn't be a problem for voice audio though.

ADPCM vs. MP3

Reply #5 –
If you're lazy, I've done it for you:

20-20000_ORIG.flac (677.4 KB)
20-20000_IMA_ADPCM.wav (432.1 KB)
20-20000_MP3.mp3 (196.2 KB)

The file 20-20000_ORIG.flac is a 44.1/16/mono sine sweep going from 20 Hz to 20.000 Hz. It's 20 seconds long and the frequency is increased linearly, so frequency at x seconds is approximately x KHz (just a bit more than that). 20-20000_IMA_ADPCM.wav and 20-20000_MP3.mp3 are created by encoding the original to IMA ADPCM and mp3 @ 80 kbps (because it's mono), respectively.

As you can clearly see/hear, MP3 gets over three times smaller file-size than IMA ADPCM and still manages to provide way better sound quality. Since this is basically how ADPCM will always behave (you can't tune its behaviour), it's always going to butcher the higher frequencies just as catastrophically as it does in this example.