----- Original Message -----
> From: Diego Biurrun <[email protected]>
> To: libav development <[email protected]>
> Cc:
> Sent: Tuesday, February 28, 2012 8:02 PM
> Subject: Re: [libav-devel] [PATCH] Windows Media Audio Lossless decoder
[...]
>> +static void decode_cdlms(WmallDecodeCtx *s)
>
> And what is cdlms anyway? You have so many Doxygen comments, but
> this is not explained anywhere.
CDLMS is like a regular LMS filter, but only operates on a single channel
to reduce intra-channel redundancy. The exact acronym seems to be M$-
specific; and it expands to "Cascaded Least Mean Squared" (found it in an
M$ patent).
No need to explain that in the code, anyone who knows audio codecs knows
what an LMS filter is. (I don't know audio codecs, and even I know what
an LMS filter is.) The multi-channel variant of the above is called MCLMS
in this code and in the spec.
[...]
>> + s->ave_sum[ch] = residue + s->ave_sum[ch] -
>> + (s->ave_sum[ch] >> s->movave_scaling);
>
> Indentation is off.
[...]
>> + for (icoef = 0; icoef < s->cdlms[ich][ilms].order; icoef++)
>> + pred += s->cdlms[ich][ilms].coefs[icoef] *
>> + s->cdlms[ich][ilms].lms_prevvalues[icoef + recent];
>
> Indentation is off.
For a moment, I thought that I understood what you mean, but the two seems
to disagree. Indent it with reference to what? The '+=' or 's->' or 'pred'?
[...]
>> +static void lms_update(WmallDecodeCtx *s, int ich, int ilms, int input,
> int residue)
>
> nit: long line
I am not sure how to break it, and it's not that long a line anyway.
[...]
>> + av_dlog(s->avctx, AV_LOG_DEBUG, "RAWPCM %d bits per
> sample. "
>> + "total %d bits, remain=%d\n", bits,
>> + bits * s->num_channels * subframe_len,
> get_bits_count(&s->gb));
>
> Indentation is off.
Again, I don't understand what's wrong with indentation here.
[...]
>> + } else {
>> +/*
>> + while (get_bits_count(gb) < s->num_saved_bits &&
> get_bits1(gb) == 0) {
>> + av_dlog(s->avctx, AV_LOG_DEBUG, "skip1\n");
>> + }
>> +*/
>> + }
>
> ?
>
> Also, indentation is off.
That's something the spec says we should do, but Andreas decided
to disable it for some reason that I don't know / understand. I'd
like to keep that code around in some form, may be someday we will
come across a sample which uses that feature.
Indentation has been taken care of mostly, here and elsewhere. I am
not sure why Andreas made all the comments doxy, but I have changed
them all to normal comments now. The original bitstream parser code
was not in good shape, cosmetically and otherwise. I tried to fix
some of it, the rest will be fixed as I come across them.
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