mirror of
https://github.com/Rockbox/rockbox.git
synced 2025-11-23 03:52:45 -05:00
Some quality improvements in the mp3 encoder engine. For more details
see FS#9007. git-svn-id: svn://svn.rockbox.org/rockbox/trunk@17679 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Antonius Hellmann
parent
75cac2c604
commit
758072173e
2 changed files with 528 additions and 327 deletions
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@ -75,7 +75,7 @@ typedef struct {
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uint32_t address3;
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long quantStep;
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long additStep;
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long max_val;
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uint32_t max_val;
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} side_info_t;
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typedef struct {
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@ -119,8 +119,9 @@ struct huffcodebig {
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static short mfbuf [2*(1152+512)] IBSS_ATTR; /* 3328 Bytes */
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static int sb_data [2][2][18][SBLIMIT] IBSS_ATTR; /* 13824 Bytes */
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static int mdct_freq [SAMPL2] IBSS_ATTR; /* 9216 Bytes */
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static short enc_data [SAMPL2] IBSS_ATTR; /* 4608 Bytes */
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static int mdct_freq [SAMPL2] IBSS_ATTR; /* 2304 Bytes */
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static char mdct_sign [SAMPL2] IBSS_ATTR; /* 576 Bytes */
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static short enc_data [SAMPL2] IBSS_ATTR; /* 1152 Bytes */
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static uint32_t scalefac [23] IBSS_ATTR; /* 92 Bytes */
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static BF_Data CodedData IBSS_ATTR; /* 1056 Bytes */
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static int ca [8] IBSS_ATTR; /* 32 Bytes */
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@ -175,6 +176,7 @@ static unsigned samp_per_frame IBSS_ATTR;
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static config_t cfg IBSS_ATTR;
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static char *res_buffer;
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static int32_t err IBSS_ATTR;
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static uint8_t band_scale_f[22];
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static const uint8_t ht_count_const[2][2][16] =
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{ { { 1, 5, 4, 5, 6, 5, 4, 4, 7, 3, 6, 0, 7, 2, 3, 1 }, /* table0 */
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@ -834,8 +836,8 @@ static const int win_const[18][4] = {
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{ 134, -146,-3352,-3072 } };
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/* forward declarations */
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static int HuffmanCode( short *ix, int *xr, uint32_t begin, uint32_t end, int table);
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static int HuffmanCod1( short *ix, int *xr, uint32_t begin, uint32_t end, int table);
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static int HuffmanCode( short *ix, char *xr_sign, uint32_t begin, uint32_t end, int table);
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static int HuffmanCod1( short *ix, char *xr_sign, uint32_t begin, uint32_t end, int table);
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static void putbits(uint32_t val, uint32_t nbit);
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static int find_best_2( short *ix, uint32_t start, uint32_t end, const uint32_t *table,
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uint32_t len, int *bits);
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@ -892,14 +894,16 @@ static void encodeSideInfo( side_info_t si[2][2] )
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{
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side_info_t *gi = &si[gr][ch];
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putlong( gi->part2_3_length, 12 );
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putlong((gi->part2_3_length+42),12 ); /* add scale_facs array size */
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putlong( gi->address3>>1, 9 );
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putlong( gi->global_gain, 8 );
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putlong( gi->table_select[0], 10 );
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putlong( 9, 4 ); /* set scale_facs compr type */
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putlong( gi->table_select[0], 6 );
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putlong( gi->table_select[1], 5 );
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putlong( gi->table_select[2], 5 );
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putlong( gi->region_0_1, 7 );
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putlong( gi->table_select[3], 3 );
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putlong( 1 , 2 ); /* set scale_facs to 1bit */
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putlong( gi->table_select[3], 1 );
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}
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}
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else
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@ -911,14 +915,16 @@ static void encodeSideInfo( side_info_t si[2][2] )
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{
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side_info_t *gi = &si[0][ch];
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putlong( gi->part2_3_length, 12);
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putlong( gi->address3>>1, 9);
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putlong( gi->global_gain, 8);
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putlong( gi->table_select[0], 15);
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putlong( gi->table_select[1], 5);
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putlong( gi->table_select[2], 5);
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putlong( gi->region_0_1, 7);
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putlong( gi->table_select[3], 2);
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putlong((gi->part2_3_length+42),12 ); /* add scale_facs array size */
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putlong( gi->address3>>1, 9 );
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putlong( gi->global_gain, 8 );
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putlong( 0xCA, 9 ); /* set scale_facs compr type */
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putlong( gi->table_select[0], 6 );
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putlong( gi->table_select[1], 5 );
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putlong( gi->table_select[2], 5 );
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putlong( gi->region_0_1 , 7 );
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putlong( 1 , 1 ); /* set scale_facs to 1bit */
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putlong( gi->table_select[3], 1 );
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}
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}
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/* flush remaining bits */
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@ -927,7 +933,7 @@ static void encodeSideInfo( side_info_t si[2][2] )
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/* Note the discussion of huffmancodebits() on pages 28 and 29 of the IS,
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as well as the definitions of the side information on pages 26 and 27. */
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static void Huffmancodebits( short *ix, int *xr, side_info_t *gi )
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static void Huffmancodebits( short *ix, char *xr_sign, side_info_t *gi )
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{
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int region1 = gi->address1;
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int region2 = gi->address2;
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@ -935,18 +941,27 @@ static void Huffmancodebits( short *ix, int *xr, side_info_t *gi )
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int count1 = bigvals + (gi->count1 << 2);
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int stuffBits = 0;
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int bits = 0;
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int i, v;
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for(i=v=0; i<32; i+=2)
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v |= band_scale_f[i>>1] << (30-i);
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putbits(v, 32); // store scale_facs (part1)
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for(v=0; i<42; i+=2)
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v |= band_scale_f[i>>1] << (40-i);
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putbits(v, 10); // store scale_facs (part2)
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if(region1 > 0)
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bits += HuffmanCode(ix, xr, 0 , region1, gi->table_select[0]);
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bits += HuffmanCode(ix, xr_sign, 0 , region1, gi->table_select[0]);
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if(region2 > region1)
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bits += HuffmanCode(ix, xr, region1, region2, gi->table_select[1]);
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bits += HuffmanCode(ix, xr_sign, region1, region2, gi->table_select[1]);
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if(bigvals > region2)
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bits += HuffmanCode(ix, xr, region2, bigvals, gi->table_select[2]);
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bits += HuffmanCode(ix, xr_sign, region2, bigvals, gi->table_select[2]);
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if(count1 > bigvals)
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bits += HuffmanCod1(ix, xr, bigvals, count1, gi->table_select[3]);
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bits += HuffmanCod1(ix, xr_sign, bigvals, count1, gi->table_select[3]);
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if((stuffBits = gi->part2_3_length - bits) > 0)
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{
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@ -961,15 +976,15 @@ static void Huffmancodebits( short *ix, int *xr, side_info_t *gi )
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}
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}
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int HuffmanCod1( short *ix, int *xr, uint32_t begin, uint32_t end, int tbl)
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int HuffmanCod1( short *ix, char *xr_sign, uint32_t begin, uint32_t end, int tbl)
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{
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uint32_t cc=0, sz=0;
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uint32_t i, d, p;
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int sumbit=0, s=0, l=0, v, w, x, y;
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#define sgnv (xr[i+0] < 0 ? 1 : 0)
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#define sgnw (xr[i+1] < 0 ? 1 : 0)
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#define sgnx (xr[i+2] < 0 ? 1 : 0)
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#define sgny (xr[i+3] < 0 ? 1 : 0)
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#define sgnv xr_sign[i+0]
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#define sgnw xr_sign[i+1]
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#define sgnx xr_sign[i+2]
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#define sgny xr_sign[i+3]
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for(i=begin; i<end; i+=4)
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{
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@ -982,20 +997,20 @@ int HuffmanCod1( short *ix, int *xr, uint32_t begin, uint32_t end, int tbl)
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switch(p)
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{
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case 0: l=0; s = 0; break;
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case 1: l=1; s = sgnv; break;
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case 2: l=1; s = sgnw; break;
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case 3: l=2; s = (sgnv << 1) + sgnw; break;
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case 4: l=1; s = sgnx; break;
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case 5: l=2; s = (sgnv << 1) + sgnx; break;
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case 1: l=1; s = sgny; break;
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case 2: l=1; s = sgnx; break;
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case 3: l=2; s = (sgnx << 1) + sgny; break;
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case 4: l=1; s = sgnw; break;
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case 5: l=2; s = (sgnw << 1) + sgny; break;
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case 6: l=2; s = (sgnw << 1) + sgnx; break;
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case 7: l=3; s = (sgnv << 2) + (sgnw << 1) + sgnx; break;
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case 8: l=1; s = sgny; break;
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case 7: l=3; s = (sgnw << 2) + (sgnx << 1) + sgny; break;
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case 8: l=1; s = sgnv; break;
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case 9: l=2; s = (sgnv << 1) + sgny; break;
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case 10: l=2; s = (sgnw << 1) + sgny; break;
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case 11: l=3; s = (sgnv << 2) + (sgnw << 1) + sgny; break;
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case 12: l=2; s = (sgnx << 1) + sgny; break;
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case 13: l=3; s = (sgnv << 2) + (sgnx << 1) + sgny; break;
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case 14: l=3; s = (sgnw << 2) + (sgnx << 1) + sgny; break;
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case 10: l=2; s = (sgnv << 1) + sgnx; break;
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case 11: l=3; s = (sgnv << 2) + (sgnx << 1) + sgny; break;
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case 12: l=2; s = (sgnv << 1) + sgnw; break;
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case 13: l=3; s = (sgnv << 2) + (sgnw << 1) + sgny; break;
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case 14: l=3; s = (sgnv << 2) + (sgnw << 1) + sgnx; break;
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case 15: l=4; s = (sgnv << 3) + (sgnw << 2) + (sgnx << 1) + sgny; break;
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}
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@ -1012,13 +1027,13 @@ int HuffmanCod1( short *ix, int *xr, uint32_t begin, uint32_t end, int tbl)
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}
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/* Implements the pseudocode of page 98 of the IS */
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int HuffmanCode( short *ix, int *xr, uint32_t begin, uint32_t end, int table)
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int HuffmanCode(short *ix, char *xr_sign, uint32_t begin, uint32_t end, int table)
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{
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uint32_t cc=0, sz=0, code;
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uint32_t i, xl=0, yl=0, idx;
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int x, y, bit, sumbit=0;
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#define sign_x (xr[i+0] < 0 ? 1 : 0)
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#define sign_y (xr[i+1] < 0 ? 1 : 0)
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#define sign_x xr_sign[i+0]
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#define sign_y xr_sign[i+1]
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if(table == 0)
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return 0;
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@ -1057,6 +1072,13 @@ int HuffmanCode( short *ix, int *xr, uint32_t begin, uint32_t end, int table)
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{
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if(y > 14)
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{
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if(bit + linbits + 1 > 32)
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{
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putlong( code, bit );
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sumbit += bit;
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code = bit = 0;
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}
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code = (code << linbits) | yl;
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bit += linbits;
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}
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@ -1324,16 +1346,29 @@ int calc_runlen( short *ix, side_info_t *si )
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/*************************************************************************/
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int quantize_int(int *xr, short *ix, side_info_t *si)
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{
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int i, s, frac_pow[] = { 0x10000, 0xd745, 0xb505, 0x9838 };
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unsigned int i, idx, s, frac_pow[] = { 0x10000, 0xd745, 0xb505, 0x9838 };
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s = frac_pow[si->quantStep & 3] >> si->quantStep / 4;
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/* check for integer overflow */
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if(((si->max_val + 256) >> 8) * s >= (1622 << 8))
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/* check for possible 'out of range' values */
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if(((si->max_val + 256) >> 8) * s >= (65536 << 8))
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return 0;
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if(((si->max_val + 256) >> 8) * s < (4096 << 8))
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{ /* all values fit the table size */
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for(i=SAMPL2; i--; )
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ix[i] = int2idx[(abs(xr[i]) * s + 0x8000) >> 16];
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ix[i] = int2idx[(xr[i] * s + 0x8000) >> 16];
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}
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else
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{ /* check each index wether it fits the table */
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for(i=SAMPL2; i--; )
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{
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idx = (xr[i] * s + 0x08000) >> 16;
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if(idx > 4095) ix[i] = int2idx[(idx + 8) >> 4] << 3;
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else ix[i] = int2idx[idx];
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}
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}
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return 1;
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}
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@ -1404,9 +1439,9 @@ int quantize_and_count_bits(int *xr, short *ix, side_info_t *si)
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return bits;
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}
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/***********************************************************************/
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/* The code selects the best quantStep for a particular set of scalefacs */
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/***********************************************************************/
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/************************************************************************/
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/* The code selects the best quantStep for a particular set of scalefacs*/
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/************************************************************************/
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int inner_loop(int *xr, int max_bits, side_info_t *si)
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{
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int bits;
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@ -2100,12 +2135,45 @@ static inline void byte_swap_frame32(uint32_t *dst, uint32_t *src,
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} /* byte_swap_frame32 */
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#endif /* ROCKBOX_LITTLE_ENDIAN */
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void set_scale_facs(int *mdct_freq)
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{
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unsigned int i, is, ie, k, s;
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int max_freq_val, avrg_freq_val;
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/* calc average of first 256 frequency values */
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for(avrg_freq_val=i=0; i<256; i++)
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avrg_freq_val += mdct_freq[i];
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avrg_freq_val >>= 8;
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/* if max of current band is smaller than average, increase precision */
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/* last band keeps untouched (not scaled) */
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for(is=k=0; is<scalefac[21]; k++)
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{
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max_freq_val = 0;
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for(i=is, ie=scalefac[k+1]; i<ie; i++)
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if(max_freq_val < mdct_freq[i])
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max_freq_val = mdct_freq[i];
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for(s=0; s<3; s++)
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if((max_freq_val<<s) > avrg_freq_val)
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break;
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band_scale_f[k] = (unsigned char)s;
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for(i=is; s && i<ie; i++)
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mdct_freq[i] <<= s;
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is = ie;
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}
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}
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STATICIRAM void encode_frame(char *buffer, struct enc_chunk_hdr *chunk)
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ICODE_ATTR;
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STATICIRAM void encode_frame(char *buffer, struct enc_chunk_hdr *chunk)
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{
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int gr, gr_cnt;
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int max, min;
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uint32_t max;
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/* encode one mp3 frame in this loop */
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CodedData.bitpos = 0;
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@ -2120,7 +2188,8 @@ STATICIRAM void encode_frame(char *buffer, struct enc_chunk_hdr *chunk)
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cfg.mpg.padding = 0;
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cfg.mean_bits = (8 * cfg.byte_per_frame + 8 * cfg.mpg.padding
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- cfg.sideinfo_len) / cfg.granules / cfg.channels;
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- cfg.sideinfo_len) / cfg.granules / cfg.channels
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- 42; // reserved for scale_facs
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/* shift out old samples */
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memcpy(mfbuf, mfbuf + 2*cfg.granules*576, 4*512);
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@ -2175,11 +2244,10 @@ STATICIRAM void encode_frame(char *buffer, struct enc_chunk_hdr *chunk)
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}
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}
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/* Perform imdct of 18 previous + 18 current subband samples
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for integer precision do this loop twice (if neccessary)
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*/
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shift = k = 14;
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for(ii=0; ii<2 && k; ii++)
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/* Perform imdct of 18 previous + 18 current subband samples */
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/* for integer precision do this loop again (if neccessary) */
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shift = 14 - (cfg.cod_info[gr][ch].additStep >> 2);
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for(k=1,ii=0; ii<3 && k; ii++)
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{
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int *mdct = mdct_freq;
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int band;
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@ -2230,30 +2298,41 @@ STATICIRAM void encode_frame(char *buffer, struct enc_chunk_hdr *chunk)
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}
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}
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max = min = 0;
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max = 0;
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for(k=0; k<576; k++)
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{
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if(mdct_freq[k] < 0)
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{
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mdct_sign[k] = 1; /* negative */
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mdct_freq[k] = shft13(-mdct_freq[k]);
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}
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else
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{
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mdct_sign[k] = 0; /* positive */
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mdct_freq[k] = shft13(mdct_freq[k]);
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if(max < mdct_freq[k]) max = mdct_freq[k];
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if(min > mdct_freq[k]) min = mdct_freq[k];
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}
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max = (max > -min) ? max : -min;
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cfg.cod_info[gr][ch].max_val = (long)max;
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if(max < (uint32_t)mdct_freq[k])
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max = (uint32_t)mdct_freq[k];
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}
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cfg.cod_info[gr][ch].max_val = max;
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/* calc new shift for higher integer precision */
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for(k=0; max<(0x3c00>>k); k++);
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shift = 12 - k;
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for(k=0; max<(uint32_t)(0x7800>>k); k++) shift--;
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for( ; (max>>k)>=(uint32_t)0x10000; k++) shift++;
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if(shift < 0) shift = 0;
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}
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cfg.cod_info[gr][ch].quantStep +=
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cfg.cod_info[gr][ch].additStep;
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|
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set_scale_facs(mdct_freq);
|
||||
|
||||
/* bit and noise allocation */
|
||||
iteration_loop(mdct_freq, &cfg.cod_info[gr][ch],
|
||||
gr_cnt--);
|
||||
/* write the frame to the bitstream */
|
||||
Huffmancodebits(enc_data, mdct_freq,
|
||||
Huffmancodebits(enc_data, mdct_sign,
|
||||
&cfg.cod_info[gr][ch]);
|
||||
|
||||
cfg.cod_info[gr][ch].quantStep -=
|
||||
|
|
|
|||
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Reference in a new issue