ALAC decoder for VS1063a available (experimental)

Designing hardware that uses VLSI Solution's devices as slave codecs such as an external MP3 decoder chip for a host microcontroller.
Post Reply
User avatar
Henrik
VLSI Staff
Posts: 1102
Joined: Tue 2010-06-22 14:10

ALAC decoder for VS1063a available (experimental)

Post by Henrik » Mon 2014-07-21 13:28

Hello, all!

An experimental ALAC (Apple Lossless Audio Codec, a.k.a. Apple Lossless) decoder is now available for VS1063a. It is part of the VS1063a Patches set, and can be downloaded from
http://www.vlsi.fi/en/support/software/ ... tches.html

We welcome comments from early testers, preferably here, but alternatively at support@vlsi.fi.

Kind regards,
- Henrik
Good signatures never die. They just fade away.

incrediball
User
Posts: 13
Joined: Fri 2011-01-14 0:04

Re: ALAC decoder for VS1063a available (experimental)

Post by incrediball » Tue 2015-07-07 4:01

Is there any chance that this could be done for the VS1053?

User avatar
pasi
VLSI Staff
Posts: 1474
Joined: Thu 2010-07-15 16:04

Re: ALAC decoder for VS1063a available (experimental)

Post by pasi » Tue 2015-07-07 10:12

Unfortunately not. The ALAC decoder depends on both the stream buffer and audio buffer relocation / sizing features of the ROM firmware, and thus need vs1063a to work.

vs1063a is pin-compatible with vs1053b. Also see vs1163a and vs8063a if you don't need mp3 encoding and decoding.
Visit https://www.facebook.com/VLSISolution VLSI Solution on Facebook

incrediball
User
Posts: 13
Joined: Fri 2011-01-14 0:04

Re: ALAC decoder for VS1063a available (experimental)

Post by incrediball » Thu 2015-07-09 7:25

Thanks for your reply. We don't have the option of using another IC because we would like to add the feature to existing hardware that has been manufactured using the VS1053. Is information on ALAC readily available? We could possibly decode it in our microcontroller (ARM-M4 at 96MHz).

User avatar
pasi
VLSI Staff
Posts: 1474
Joined: Thu 2010-07-15 16:04

Re: ALAC decoder for VS1063a available (experimental)

Post by pasi » Thu 2015-07-09 12:07

Information about ALAC is available, from various sources, including http://alac.macosforge.org/ and a few example codes (supposedly written from reverse-engineered specifications) like Shairport and FFMPEG/libavcodec.

You would also need to implement functions to handle the mpeg-4 container.

The main issue with ALAC is the large block size, so a lot of data needs to be processed before the first samples can be output. The data for left and right are also not interleaved, but one after the other. The same applies to FLAC, but FLAC is a bit lighter with its CPU consumption.
Visit https://www.facebook.com/VLSISolution VLSI Solution on Facebook

Post Reply