[FFmpeg-devel] [PATCH] [Issue 632] AAC: Decode TNS order zero properly from the bitstream

Robert Swain robert.swain
Fri Sep 12 12:06:29 CEST 2008


2008/9/12 Alex Converse <alex.converse at gmail.com>:
> As per tns_data() from the spec, direction and coef_compression are
> not coded if order == 0.

Yes, looks fine and correct to me. Michael - do you want me to request
your OK for such patches or would you prefer I just apply them if I
think they're OK?

> Even after this, something is still wrong with al04_44 (Issue 632) as
> we are only getting 8 bits of conformance.

It may be useful to analyse where in the stream the significant
differences occur in case it's a few isolated cases spread across the
file. I used this technique previously with success. Basically I
printed out the channel element types for each channel, found the
position of the difference in terms of samples (I used `cmp -l` and
calculated from that bearing in mind that the first AAC frame does not
get output, but whatever suits you), and then look at the code and the
tools used for that channel element to figure out where it's going

Also, if you have a script for testing all these files to present
whether they decode or not and their level of conformance, that would
be appreciated. :)


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