[FFmpeg-devel] [PATCH] AAC Decoder round 4

[Robert Swain]

2008/7/30 Michael Niedermayer <michaelni at gmx.at>:
> On Wed, Jul 30, 2008 at 07:24:44PM +0100, Robert Swain wrote:

>> Again, I thought you mean line-breaks in the code, not in how the
>> patch was coming through in the e-mail. Again, see attached
>> (20080728-1344-refactor_excluded_channels.diff).

> [...]

>> Index: aac.c
>> ===================================================================
>> --- aac.c     (revision 2918)
>> +++ aac.c     (working copy)
>> @@ -279,7 +279,7 @@
>>      int dyn_rng_sgn[17];                            ///< DRC sign information; 0 - positive, 1 - negative
>>      int dyn_rng_ctl[17];                            ///< DRC magnitude information
>>      int exclude_mask[MAX_CHANNELS];                 ///< Channels to be excluded from DRC processing.
>> -    int additional_excluded_chns[MAX_CHANNELS];     /**< The exclude_mask bits are
>> +    int additional_excluded_chns[MAX_CHANNELS / 7]; /**< The exclude_mask bits are
>>                                                          coded in groups of 7 with 1 bit preceeding each group (except the first)
>>                                                          indicating that 7 more mask bits are coded. */
>>      int band_incr;                                  ///< Number of DRC bands greater than 1 having DRC info.
>> @@ -1607,21 +1607,13 @@
>>   * @return  Returns number of bytes consumed.
>>   */
>>  static int decode_drc_channel_exclusions(AACContext * ac, GetBitContext * gb) {
>> -    int i;
>> -    int n = 1;
>> -    int num_excl_chan = 7;
>> +    int i, n;
>>
>> -    for (i = 0; i < 7; i++)
>> -         ac->che_drc.exclude_mask[i] = get_bits1(gb);
>> +    for (i=0, n=0; i < MAX_CHANNELS && (((i+1)%7) || (ac->che_drc.additional_excluded_chns[n++] = get_bits1(gb))); i++)
>> +        ac->che_drc.exclude_mask[i] = get_bits1(gb);
>
> i think this is a little obfuscated
>
> what i meant was more along the lines of:
>
> do{
>    for (i = 0; i < 7; i++)
>        ac->che_drc.exclude_mask[i+X] = get_bits1(gb);
>    X+= 7;
> }while(get_bits1(gb));
>
> (note this likely is not correct, its just to show what i meant)

See attached. I agree it's much more readable.

Rob
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