AW: AW: [Flac-dev] Incomplete format description?

[Tor-Einar Jarnbjo]

Torsdag, 23 januar 2003, skrev "Tor-Einar Jarnbjo" <Tor-Einar_Jarnbjo at grosch-
link.de>:

>- My implementation seems to decode fixed subframes now, but the lpc
>subframes contains nothing but noise, and the bitstream is out of 
sync after
>reading one. The source code I'm using for decoding the lpc subframe is
>available here: http://user.cs.tu-berlin.de/~bjote/Subframe.java 
and the
>relevant part starts on line 218. I would appreciate if someone 
would take a
>look at it and see if they find any obvious mistakes (the code should 
be
>quite easy to read).

To be more precise, I here have an example of a frame, which I am 
not able to decode properly:

11111111 11111000 
frame sync and reserved bits

01011001 10011000 
block size = 0101 -> 4608
sample rate = 1001 -> 44100
channel ass. = 1001
sample size = 100 -> 16 bits
0 bit padding

11000010 10101000 
frame number = 168

10001011 
CRC (not checked)

01001000
LPC subframe
order = 5
no bits wasted

11111110 00001111 
11111111 10001001 
00000000 00010101 
01100000 00000111
00111111 11101000
5 warmup samples

00010101 10100101 00010001 11110000
ppppssss s0011223 344mm

So, this is where I fail. The bits should have the following meaning:

p: coefficient precision = 2
s: coefficient shift = 11
0-4: order * coefficient precision (2 * 5) bits
     containing the coefficients
m: residual coding method = 2(!)

According to the format description, the coding method has to be 0.

I've been using libFLAC 1.0.4 to encode the stream.


Tor



===================================================================
EASY and FREE access to your email anywhere: http://Mailreader.com/
===================================================================