[FFmpeg-cvslog] r18888 - in trunk/libavcodec: ac3dec_data.c ac3dec_data.h eac3dec.c

[Justin Ruggles]

Michael Niedermayer wrote:
> On Thu, May 21, 2009 at 02:15:03AM +0200, jbr wrote:
>> Author: jbr
>> Date: Thu May 21 02:15:03 2009
>> New Revision: 18888
>>
>> Log:
>> eac3dec: make GAQ dequantization 24-bit
>>
>> Modified:
>>    trunk/libavcodec/ac3dec_data.c
>>    trunk/libavcodec/ac3dec_data.h
>>    trunk/libavcodec/eac3dec.c
>>
>> Modified: trunk/libavcodec/ac3dec_data.c
>> ==============================================================================
>> --- trunk/libavcodec/ac3dec_data.c	Thu May 21 02:09:23 2009	(r18887)
>> +++ trunk/libavcodec/ac3dec_data.c	Thu May 21 02:15:03 2009	(r18888)
>> @@ -87,19 +87,18 @@ const int16_t ff_eac3_gaq_remap_2_4_a[9]
>>  /**
>>   * Table E3.6, Gk=2 & Gk=4, B
>>   * Large mantissa inverse quantization, negative mantissa remapping offsets
>> - * Table values from the spec are right-shifted by 8 to simplify calculations.
>>   * ff_eac3_gaq_remap_3_4_b[hebap-8][Gk=2,4]
>>   */
>> -const int8_t ff_eac3_gaq_remap_2_4_b[9][2] = {
>> -    { -22,  -5 },
>> -    { -46, -20 },
>> -    { -56, -26 },
>> -    { -60, -29 },
>> -    { -62, -31 },
>> -    { -63, -32 },
>> -    { -64, -32 },
>> -    { -64, -32 },
>> -    { -64, -32 },
>> +const int16_t ff_eac3_gaq_remap_2_4_b[9][2] = {
>> +    {  -5461, -1170 },
>> +    { -11703, -4915 },
>> +    { -14199, -6606 },
>> +    { -15327, -7412 },
>> +    { -15864, -7805 },
>> +    { -16126, -7999 },
>> +    { -16255, -8096 },
>> +    { -16320, -8144 },
>> +    { -16352, -8168 }
>>  };
>>  
>>  static const int16_t vq_hebap1[4][6] = {
>>
>> Modified: trunk/libavcodec/ac3dec_data.h
>> ==============================================================================
>> --- trunk/libavcodec/ac3dec_data.h	Thu May 21 02:09:23 2009	(r18887)
>> +++ trunk/libavcodec/ac3dec_data.h	Thu May 21 02:15:03 2009	(r18888)
>> @@ -29,7 +29,7 @@ extern const uint8_t ff_eac3_hebap_tab[6
>>  extern const uint8_t ff_eac3_bits_vs_hebap[20];
>>  extern const int16_t ff_eac3_gaq_remap_1[12];
>>  extern const int16_t ff_eac3_gaq_remap_2_4_a[9][2];
>> -extern const int8_t  ff_eac3_gaq_remap_2_4_b[9][2];
>> +extern const int16_t ff_eac3_gaq_remap_2_4_b[9][2];
>>  
>>  extern const int16_t (* const ff_eac3_mantissa_vq[8])[6];
>>  extern const uint8_t ff_eac3_frm_expstr[32][6];
>>
>> Modified: trunk/libavcodec/eac3dec.c
>> ==============================================================================
>> --- trunk/libavcodec/eac3dec.c	Thu May 21 02:09:23 2009	(r18887)
>> +++ trunk/libavcodec/eac3dec.c	Thu May 21 02:15:03 2009	(r18888)
>> @@ -178,19 +178,21 @@ void ff_eac3_decode_transform_coeffs_aht
>>                  if (mant == -(1 << (gbits-1))) {
>>                      /* large mantissa */
>>                      int b;
>> -                    mant = get_sbits(gbc, bits-2+log_gain) << (26-log_gain-bits);
>> +                    int mbits = bits - (2 - log_gain);
>> +                    mant = get_sbits(gbc, mbits);
>> +                    mant <<= (23 - (mbits - 1));
>>                      /* remap mantissa value to correct for asymmetric quantization */
>>                      if (mant >= 0)
>> -                        b = 32768 >> (log_gain+8);
>> +                        b = 1 << (23 - (mbits - 1));
> 
>>                      else
>> -                        b = ff_eac3_gaq_remap_2_4_b[hebap-8][log_gain-1];
>> -                    mant += (ff_eac3_gaq_remap_2_4_a[hebap-8][log_gain-1] * (mant>>8) + b) >> 7;
> 
>> +                        b = ff_eac3_gaq_remap_2_4_b[hebap-8][log_gain-1] << 8;
>> +                    mant += (((ff_eac3_gaq_remap_2_4_a[hebap-8][log_gain-1] << 8) * (int64_t)mant) >> 23) + b;
> 
> mant += ((ff_eac3_gaq_remap_2_4_a[hebap-8][log_gain-1] * (int64_t)mant) >> 15) + b;
> 
> 
>>                  } else {
>>                      /* small mantissa, no GAQ, or Gk=1 */
>>                      mant <<= 24 - bits;
>>                      if (!log_gain) {
>>                          /* remap mantissa value for no GAQ or Gk=1 */
>> -                        mant += (ff_eac3_gaq_remap_1[hebap-8] * (mant>>8)) >> 7;
> 
>> +                        mant += ((ff_eac3_gaq_remap_1[hebap-8] << 8) * (int64_t)mant) >> 23;
> 
> mant += (ff_eac3_gaq_remap_1[hebap-8] * (int64_t)mant) >> 15;
> 
> [...]

Changed. Thanks.

-Justin