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audio/mp3: Refactoring
This commit is contained in:
Hajime Hoshi
parent
7b1f3fae99
commit
cf05a581a4
146
audio/mp3/l3.go
146
audio/mp3/l3.go
@ -96,14 +96,14 @@ var (
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)
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func (f *frame) l3Requantize(gr int, ch int) {
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/* Setup sampling frequency index */
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// Setup sampling frequency index
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sfreq := f.header.sampling_frequency
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/* Determine type of block to process */
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if (f.sideInfo.win_switch_flag[gr][ch] == 1) && (f.sideInfo.block_type[gr][ch] == 2) { /* Short blocks */
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/* Check if the first two subbands
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*(=2*18 samples = 8 long or 3 short sfb's) uses long blocks */
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if f.sideInfo.mixed_block_flag[gr][ch] != 0 { /* 2 longbl. sb first */
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/* First process the 2 long block subbands at the start */
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// Determine type of block to process
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if (f.sideInfo.win_switch_flag[gr][ch] == 1) && (f.sideInfo.block_type[gr][ch] == 2) { // Short blocks
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// Check if the first two subbands
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// (=2*18 samples = 8 long or 3 short sfb's) uses long blocks
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if f.sideInfo.mixed_block_flag[gr][ch] != 0 { // 2 longbl. sb first
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// First process the 2 long block subbands at the start
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sfb := 0
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next_sfb := sfBandIndicesSet[sfreq].l[sfb+1]
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for i := 0; i < 36; i++ {
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@ -113,15 +113,15 @@ func (f *frame) l3Requantize(gr int, ch int) {
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}
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f.requantizeProcessLong(gr, ch, i, sfb)
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}
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/* And next the remaining,non-zero,bands which uses short blocks */
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// And next the remaining,non-zero,bands which uses short blocks
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sfb = 3
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next_sfb = sfBandIndicesSet[sfreq].s[sfb+1] * 3
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win_len := sfBandIndicesSet[sfreq].s[sfb+1] -
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sfBandIndicesSet[sfreq].s[sfb]
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for i := 36; i < int(f.sideInfo.count1[gr][ch]); /* i++ done below! */ {
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/* Check if we're into the next scalefac band */
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if i == next_sfb { /* Yes */
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// Check if we're into the next scalefac band
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if i == next_sfb {
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sfb++
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next_sfb = sfBandIndicesSet[sfreq].s[sfb+1] * 3
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win_len = sfBandIndicesSet[sfreq].s[sfb+1] -
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@ -135,13 +135,13 @@ func (f *frame) l3Requantize(gr int, ch int) {
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}
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}
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} else { /* Only short blocks */
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} else { // Only short blocks
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sfb := 0
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next_sfb := sfBandIndicesSet[sfreq].s[sfb+1] * 3
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win_len := sfBandIndicesSet[sfreq].s[sfb+1] -
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sfBandIndicesSet[sfreq].s[sfb]
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for i := 0; i < int(f.sideInfo.count1[gr][ch]); /* i++ done below! */ {
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/* Check if we're into the next scalefac band */
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// Check if we're into the next scalefac band
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if i == next_sfb {
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sfb++
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next_sfb = sfBandIndicesSet[sfreq].s[sfb+1] * 3
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@ -156,7 +156,7 @@ func (f *frame) l3Requantize(gr int, ch int) {
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}
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}
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}
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} else { /* Only long blocks */
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} else { // Only long blocks
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sfb := 0
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next_sfb := sfBandIndicesSet[sfreq].l[sfb+1]
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for i := 0; i < int(f.sideInfo.count1[gr][ch]); i++ {
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@ -172,13 +172,13 @@ func (f *frame) l3Requantize(gr int, ch int) {
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func (f *frame) l3Reorder(gr int, ch int) {
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re := make([]float32, 576)
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sfreq := f.header.sampling_frequency /* Setup sampling freq index */
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/* Only reorder short blocks */
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if (f.sideInfo.win_switch_flag[gr][ch] == 1) && (f.sideInfo.block_type[gr][ch] == 2) { /* Short blocks */
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/* Check if the first two subbands
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*(=2*18 samples = 8 long or 3 short sfb's) uses long blocks */
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sfreq := f.header.sampling_frequency // Setup sampling freq index
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// Only reorder short blocks
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if (f.sideInfo.win_switch_flag[gr][ch] == 1) && (f.sideInfo.block_type[gr][ch] == 2) { // Short blocks
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// Check if the first two subbands
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// (=2*18 samples = 8 long or 3 short sfb's) uses long blocks
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sfb := 0
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/* 2 longbl. sb first */
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// 2 longbl. sb first
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if f.sideInfo.mixed_block_flag[gr][ch] != 0 {
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sfb = 3
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}
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@ -189,13 +189,13 @@ func (f *frame) l3Reorder(gr int, ch int) {
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i = 0
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}
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for i < 576 {
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/* Check if we're into the next scalefac band */
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// Check if we're into the next scalefac band
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if i == next_sfb {
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/* Copy reordered data back to the original vector */
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// Copy reordered data back to the original vector
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for j := 0; j < 3*win_len; j++ {
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f.mainData.is[gr][ch][3*sfBandIndicesSet[sfreq].s[sfb]+j] = re[j]
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}
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/* Check if this band is above the rzero region,if so we're done */
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// Check if this band is above the rzero region,if so we're done
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if i >= f.sideInfo.count1[gr][ch] {
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return
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}
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@ -203,14 +203,14 @@ func (f *frame) l3Reorder(gr int, ch int) {
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next_sfb = sfBandIndicesSet[sfreq].s[sfb+1] * 3
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win_len = sfBandIndicesSet[sfreq].s[sfb+1] - sfBandIndicesSet[sfreq].s[sfb]
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}
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for win := 0; win < 3; win++ { /* Do the actual reordering */
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for win := 0; win < 3; win++ { // Do the actual reordering
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for j := 0; j < win_len; j++ {
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re[j*3+win] = f.mainData.is[gr][ch][i]
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i++
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}
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}
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}
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/* Copy reordered data of last band back to original vector */
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// Copy reordered data of last band back to original vector
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for j := 0; j < 3*win_len; j++ {
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f.mainData.is[gr][ch][3*sfBandIndicesSet[sfreq].s[12]+j] = re[j]
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}
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@ -224,20 +224,20 @@ var (
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func (f *frame) stereoProcessIntensityLong(gr int, sfb int) {
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is_ratio_l := float32(0)
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is_ratio_r := float32(0)
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/* Check that((is_pos[sfb]=scalefac) != 7) => no intensity stereo */
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// Check that((is_pos[sfb]=scalefac) != 7) => no intensity stereo
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is_pos := f.mainData.scalefac_l[gr][0][sfb]
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if is_pos != 7 {
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sfreq := f.header.sampling_frequency /* Setup sampling freq index */
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sfreq := f.header.sampling_frequency // Setup sampling freq index
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sfb_start := sfBandIndicesSet[sfreq].l[sfb]
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sfb_stop := sfBandIndicesSet[sfreq].l[sfb+1]
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if is_pos == 6 { /* tan((6*PI)/12 = PI/2) needs special treatment! */
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if is_pos == 6 { // tan((6*PI)/12 = PI/2) needs special treatment!
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is_ratio_l = 1.0
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is_ratio_r = 0.0
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} else {
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is_ratio_l = isRatios[is_pos] / (1.0 + isRatios[is_pos])
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is_ratio_r = 1.0 / (1.0 + isRatios[is_pos])
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}
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/* Now decode all samples in this scale factor band */
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// Now decode all samples in this scale factor band
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for i := sfb_start; i < sfb_stop; i++ {
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f.mainData.is[gr][0][i] *= is_ratio_l
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f.mainData.is[gr][1][i] *= is_ratio_r
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@ -248,24 +248,24 @@ func (f *frame) stereoProcessIntensityLong(gr int, sfb int) {
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func (f *frame) stereoProcessIntensityShort(gr int, sfb int) {
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is_ratio_l := float32(0)
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is_ratio_r := float32(0)
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sfreq := f.header.sampling_frequency /* Setup sampling freq index */
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/* The window length */
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sfreq := f.header.sampling_frequency // Setup sampling freq index
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// The window length
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win_len := sfBandIndicesSet[sfreq].s[sfb+1] - sfBandIndicesSet[sfreq].s[sfb]
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/* The three windows within the band has different scalefactors */
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// The three windows within the band has different scalefactors
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for win := 0; win < 3; win++ {
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/* Check that((is_pos[sfb]=scalefac) != 7) => no intensity stereo */
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// Check that((is_pos[sfb]=scalefac) != 7) => no intensity stereo
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is_pos := f.mainData.scalefac_s[gr][0][sfb][win]
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if is_pos != 7 {
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sfb_start := sfBandIndicesSet[sfreq].s[sfb]*3 + win_len*win
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sfb_stop := sfb_start + win_len
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if is_pos == 6 { /* tan((6*PI)/12 = PI/2) needs special treatment! */
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if is_pos == 6 { // tan((6*PI)/12 = PI/2) needs special treatment!
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is_ratio_l = 1.0
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is_ratio_r = 0.0
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} else {
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is_ratio_l = isRatios[is_pos] / (1.0 + isRatios[is_pos])
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is_ratio_r = 1.0 / (1.0 + isRatios[is_pos])
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}
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/* Now decode all samples in this scale factor band */
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// Now decode all samples in this scale factor band
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for i := sfb_start; i < sfb_stop; i++ {
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// https://github.com/technosaurus/PDMP3/issues/3
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f.mainData.is[gr][0][i] *= is_ratio_l
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@ -276,19 +276,19 @@ func (f *frame) stereoProcessIntensityShort(gr int, sfb int) {
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}
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func (f *frame) l3Stereo(gr int) {
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/* Do nothing if joint stereo is not enabled */
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// Do nothing if joint stereo is not enabled
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if (f.header.mode != 1) || (f.header.mode_extension == 0) {
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return
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}
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/* Do Middle/Side("normal") stereo processing */
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// Do Middle/Side("normal") stereo processing
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if (f.header.mode_extension & 0x2) != 0 {
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/* Determine how many frequency lines to transform */
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// Determine how many frequency lines to transform
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i := 0
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if f.sideInfo.count1[gr][0] > f.sideInfo.count1[gr][1] {
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i = 1
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}
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max_pos := int(f.sideInfo.count1[gr][i])
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/* Do the actual processing */
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// Do the actual processing
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const invSqrt2 = math.Sqrt2 / 2
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for i := 0; i < max_pos; i++ {
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left := (f.mainData.is[gr][0][i] + f.mainData.is[gr][1][i]) * invSqrt2
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@ -297,45 +297,45 @@ func (f *frame) l3Stereo(gr int) {
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f.mainData.is[gr][1][i] = right
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}
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}
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/* Do intensity stereo processing */
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// Do intensity stereo processing
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if (f.header.mode_extension & 0x1) != 0 {
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/* Setup sampling frequency index */
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// Setup sampling frequency index
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sfreq := f.header.sampling_frequency
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/* First band that is intensity stereo encoded is first band scale factor
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* band on or above count1 frequency line. N.B.: Intensity stereo coding is
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* only done for higher subbands, but logic is here for lower subbands. */
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/* Determine type of block to process */
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// First band that is intensity stereo encoded is first band scale factor
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// band on or above count1 frequency line. N.B.: Intensity stereo coding is
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// only done for higher subbands, but logic is here for lower subbands.
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// Determine type of block to process
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if (f.sideInfo.win_switch_flag[gr][0] == 1) &&
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(f.sideInfo.block_type[gr][0] == 2) { /* Short blocks */
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/* Check if the first two subbands
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*(=2*18 samples = 8 long or 3 short sfb's) uses long blocks */
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if f.sideInfo.mixed_block_flag[gr][0] != 0 { /* 2 longbl. sb first */
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for sfb := 0; sfb < 8; sfb++ { /* First process 8 sfb's at start */
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/* Is this scale factor band above count1 for the right channel? */
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(f.sideInfo.block_type[gr][0] == 2) { // Short blocks
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// Check if the first two subbands
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// (=2*18 samples = 8 long or 3 short sfb's) uses long blocks
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if f.sideInfo.mixed_block_flag[gr][0] != 0 { // 2 longbl. sb first
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for sfb := 0; sfb < 8; sfb++ { // First process 8 sfb's at start
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// Is this scale factor band above count1 for the right channel?
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if sfBandIndicesSet[sfreq].l[sfb] >= f.sideInfo.count1[gr][1] {
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f.stereoProcessIntensityLong(gr, sfb)
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}
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}
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/* And next the remaining bands which uses short blocks */
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// And next the remaining bands which uses short blocks
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for sfb := 3; sfb < 12; sfb++ {
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/* Is this scale factor band above count1 for the right channel? */
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// Is this scale factor band above count1 for the right channel?
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if sfBandIndicesSet[sfreq].s[sfb]*3 >= f.sideInfo.count1[gr][1] {
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f.stereoProcessIntensityShort(gr, sfb) /* intensity stereo processing */
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f.stereoProcessIntensityShort(gr, sfb) // intensity stereo processing
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}
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}
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} else { /* Only short blocks */
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} else { // Only short blocks
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for sfb := 0; sfb < 12; sfb++ {
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/* Is this scale factor band above count1 for the right channel? */
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// Is this scale factor band above count1 for the right channel?
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if sfBandIndicesSet[sfreq].s[sfb]*3 >= f.sideInfo.count1[gr][1] {
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f.stereoProcessIntensityShort(gr, sfb) /* intensity stereo processing */
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f.stereoProcessIntensityShort(gr, sfb) // intensity stereo processing
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}
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}
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}
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} else { /* Only long blocks */
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} else { // Only long blocks
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for sfb := 0; sfb < 21; sfb++ {
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/* Is this scale factor band above count1 for the right channel? */
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// Is this scale factor band above count1 for the right channel?
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if sfBandIndicesSet[sfreq].l[sfb] >= f.sideInfo.count1[gr][1] {
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/* Perform the intensity stereo processing */
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// Perform the intensity stereo processing
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f.stereoProcessIntensityLong(gr, sfb)
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}
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}
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@ -349,20 +349,20 @@ var (
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)
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func (f *frame) l3Antialias(gr int, ch int) {
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/* No antialiasing is done for short blocks */
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// No antialiasing is done for short blocks
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if (f.sideInfo.win_switch_flag[gr][ch] == 1) &&
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(f.sideInfo.block_type[gr][ch] == 2) &&
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(f.sideInfo.mixed_block_flag[gr][ch]) == 0 {
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return
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}
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/* Setup the limit for how many subbands to transform */
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// Setup the limit for how many subbands to transform
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sblim := 32
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if (f.sideInfo.win_switch_flag[gr][ch] == 1) &&
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(f.sideInfo.block_type[gr][ch] == 2) &&
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(f.sideInfo.mixed_block_flag[gr][ch] == 1) {
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sblim = 2
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}
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/* Do the actual antialiasing */
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// Do the actual antialiasing
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for sb := 1; sb < sblim; sb++ {
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for i := 0; i < 8; i++ {
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li := 18*sb - 1 - i
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@ -553,36 +553,36 @@ func (f *frame) l3SubbandSynthesis(gr int, ch int, out []uint8) {
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s_vec := make([]float32, 32)
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nch := f.header.numberOfChannels()
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/* Setup the n_win windowing vector and the v_vec intermediate vector */
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for ss := 0; ss < 18; ss++ { /* Loop through 18 samples in 32 subbands */
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for i := 1023; i > 63; i-- { /* Shift up the V vector */
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// Setup the n_win windowing vector and the v_vec intermediate vector
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for ss := 0; ss < 18; ss++ { // Loop through 18 samples in 32 subbands
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for i := 1023; i > 63; i-- { // Shift up the V vector
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f.v_vec[ch][i] = f.v_vec[ch][i-64]
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}
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for i := 0; i < 32; i++ { /* Copy next 32 time samples to a temp vector */
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for i := 0; i < 32; i++ { // Copy next 32 time samples to a temp vector
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s_vec[i] = f.mainData.is[gr][ch][i*18+ss]
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}
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for i := 0; i < 64; i++ { /* Matrix multiply input with n_win[][] matrix */
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for i := 0; i < 64; i++ { // Matrix multiply input with n_win[][] matrix
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sum := float32(0)
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for j := 0; j < 32; j++ {
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sum += synthNWin[i][j] * s_vec[j]
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}
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f.v_vec[ch][i] = sum
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}
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for i := 0; i < 8; i++ { /* Build the U vector */
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for j := 0; j < 32; j++ { /* <<7 == *128 */
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for i := 0; i < 8; i++ { // Build the U vector
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for j := 0; j < 32; j++ { // <<7 == *128
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u_vec[(i<<6)+j] = f.v_vec[ch][(i<<7)+j]
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u_vec[(i<<6)+j+32] = f.v_vec[ch][(i<<7)+j+96]
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}
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}
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for i := 0; i < 512; i++ { /* Window by u_vec[i] with synthDtbl[i] */
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for i := 0; i < 512; i++ { // Window by u_vec[i] with synthDtbl[i]
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u_vec[i] *= synthDtbl[i]
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}
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for i := 0; i < 32; i++ { /* Calc 32 samples,store in outdata vector */
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for i := 0; i < 32; i++ { // Calc 32 samples,store in outdata vector
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sum := float32(0)
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for j := 0; j < 16; j++ { /* sum += u_vec[j*32 + i]; */
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for j := 0; j < 16; j++ { // sum += u_vec[j*32 + i];
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sum += u_vec[(j<<5)+i]
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}
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/* sum now contains time sample 32*ss+i. Convert to 16-bit signed int */
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// sum now contains time sample 32*ss+i. Convert to 16-bit signed int
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samp := int(sum * 32767)
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if samp > 32767 {
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samp = 32767
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