[FFmpeg-cvslog] r21799 - in trunk/libavcodec: Makefile alsdec.c bgmc.c bgmc.h

[Måns Rullgård]

Thilo Borgmann <thilo.borgmann at googlemail.com> writes:

> Am 15.02.10 06:28, schrieb Mike Melanson:
>> Thilo Borgmann wrote:
>>> And the decoder currently supports 00-05 files.
>> 
>> I have staged tests for these 6 16-bit files. Linux / x86_64 / icc 11.1
>> produces different results for all files. Possibly a compiler bug. I'll
>> alert my Intel compiler contact.
>> 
>> Apart from that, here are some other curiosities:
>> 
>> For file als_02/als_02_2ch48k16b.mp4, most configs agree, but these 9
>> configurations create 9 different CRCs:
>> 
>> (command: 'ffmpeg -i als_02_2ch48k16b.mp4 -f crc -')
>> 
>>   Linux / x86_32 / icc 11.0
>>   Linux / x86_64 / icc 11.0
>>   Linux / x86_32 / llvm-svn
>>   Linux / x86_64 / icc 10.1
>>   Linux / x86_64 / icc 11.1
>>   Linux / x86_32 / icc 11.1
>>   Linux / x86_32 / gcc 3.4.6
>>   Linux / x86_32 / icc 10.1
>>   Linux / x86_64 / llvm-svn
>
> Please check these again with the patch attached. It fixes this at least
> for the Linux / x86_32 / gcc 3.4.6 case here.
>
> -Thilo
>
> Index: libavcodec/alsdec.c
> ===================================================================
> --- libavcodec/alsdec.c	(Revision 21872)
> +++ libavcodec/alsdec.c	(Arbeitskopie)
> @@ -703,10 +703,14 @@
>          *bd->use_ltp = get_bits1(gb);
>
>          if (*bd->use_ltp) {
> +            int r, c;
> +
>              bd->ltp_gain[0]   = decode_rice(gb, 1) << 3;
>              bd->ltp_gain[1]   = decode_rice(gb, 2) << 3;
>
> -            bd->ltp_gain[2]   = ltp_gain_values[get_unary(gb, 0, 4)][get_bits(gb, 2)];
> +            r = get_unary(gb, 0, 4);
> +            c = get_bits(gb, 2);
> +            bd->ltp_gain[2]   = ltp_gain_values[r][c];
>
>              bd->ltp_gain[3]   = decode_rice(gb, 2) << 3;
>              bd->ltp_gain[4]   = decode_rice(gb, 1) << 3;

This fixes gcc 3.4.6 on x86_64 as well, and the change is correct
regardless.  The order of evaluation of expressions in array indexing
is unspecified.  Please apply.

-- 
M?ns Rullg?rd
mans at mansr.com