mp3: fix reconstruction

[nihav.git] / nihav-mpeg / src / codecs / mpegaudio / mp3code.rs

diff --git a/nihav-mpeg/src/codecs/mpegaudio/mp3code.rs b/nihav-mpeg/src/codecs/mpegaudio/mp3code.rs
index 84be76a75cce058b5141d1c5705e1e004807d86d..e43988c2143bb74a80dd74daf06b643a08c9fb6c 100644 (file)
--- a/nihav-mpeg/src/codecs/mpegaudio/mp3code.rs
+++ b/nihav-mpeg/src/codecs/mpegaudio/mp3code.rs
@@ -196,7 +196,7 @@ impl MDCTContext {
             let window = if flip { &self.win12f } else { &self.win12 };
             for j in 0..3 {
                 let tmp = &mut self.tmp[j * 12..];
-                dct12(&src[i + j * 6..], tmp);
+                dct12(&src[i + j..], tmp);
                 for (el, &w) in tmp.iter_mut().zip(window.iter()) {
                     *el *= w;
                 }
@@ -467,6 +467,9 @@ impl MP3Data {
                             gr.scalefac[cb]     = br.read(bits2)? as u8;
                         }
                     }
+                    for scf in gr.scalefac[MP3_BANDS..].iter_mut() {
+                        *scf = 0;
+                    }
                     for is in gr.istereo.iter_mut() {
                         *is = 7;
                     }
@@ -482,6 +485,9 @@ impl MP3Data {
                     for scf in gr.scalefac[pivot..][..18].iter_mut() {
                         *scf        = br.read(bits2)? as u8;
                     }
+                    for scf in gr.scalefac[pivot + 18..].iter_mut() {
+                        *scf = 0;
+                    }
                     for is in gr.istereo.iter_mut() {
                         *is = 7;
                     }
@@ -605,7 +611,7 @@ impl MP3Data {
                     let coef1 = &mut coef1[0][gr_no * SAMPLES/2..];
                     let is_mode = &self.is_mode[gr_no * SAMPLES/2..];
                     let start = band_end[gr_no][bound_band[gr_no]];
-                    let end = grans[0].zero_part;
+                    let end = grans[0].zero_part.max(start);
 
                     if self.mpeg1 {
                         let coef0 = &mut coef0[start..end];
@@ -622,11 +628,13 @@ impl MP3Data {
                         let iscale = (grans[1].scalefac_compress & 1) as u8;
                         for band in 0..num_bands[gr_no] {
                             if (band_flags[gr_no][band] & IS_MODE) != 0 {
+                                let start = band_start[gr_no][band];
+                                let end   = band_end[gr_no][band];
                                 apply_istereo(&mut coef0[start..end], &mut coef1[start..end], is_mode[start], iscale, (band_flags[gr_no][band] & MS_MODE) != 0);
                             }
                         }
                     }
-                    end_freq[gr_no][1] = end_freq[gr_no][1].min(end);
+                    end_freq[gr_no][1] = end_freq[gr_no][1].max(end);
                 }
             }
             if (mode_ext & MS_MODE) != 0 {
@@ -639,7 +647,7 @@ impl MP3Data {
                         if band_start[gr_no][band] >= end {
                             break;
                         }
-                        if (band_flags[gr_no][band] & MS_MODE) != 0 {
+                        if band_flags[gr_no][band] == MS_MODE {
                             let start = band_start[gr_no][band];
                             let end   = band_end[gr_no][band];
                             super::apply_ms(&mut coef0[start..end], &mut coef1[start..end]);
@@ -662,7 +670,7 @@ impl MP3Data {
                     let mut sb = if gr.switch_point { 3 } else { 0 };
                     let mut off = switch_off;
 
-                    while sb < MP3_BANDS_SHORT {
+                    while sb <= MP3_BANDS_SHORT {
                         let band_size = MP3_SFB_SHORT_SIZE[self.sf_idx][sb];
                         for win in 0..3 {
                             for i in 0..band_size {
@@ -773,21 +781,21 @@ const DCT12_4: f32 =  0.7933533402912348;
 const DCT12_5: f32 =  0.9914448613738103;
 
 fn dct12(src: &[f32], dst: &mut [f32]) {
-    let t0 = src[0] - src[3] - src[4];
-    let t1 = src[1] - src[2] - src[5];
+    let t0 = src[0] - src[9] - src[12];
+    let t1 = src[3] - src[6] - src[15];
 
     dst[ 4] = t0 * DCT12_1 - t1 * DCT12_0;
     dst[ 7] = t0 * DCT12_0 + t1 * DCT12_1;
     dst[ 1] = -dst[4];
-    dst[10] = -dst[7];
+    dst[10] =  dst[7];
 
-    let t0 = src[1] * DCT12_1 - src[4] * DCT12_0;
-    let t1 = src[1] * DCT12_0 + src[4] * DCT12_1;
+    let t0 = src[3] * DCT12_1 - src[12] * DCT12_0;
+    let t1 = src[3] * DCT12_0 + src[12] * DCT12_1;
 
-    dst[ 3] =  src[0] * DCT12_2 + src[2] * DCT12_3 + src[3] * DCT12_4 + src[5] * DCT12_5 - t0;
-    dst[ 5] =  src[0] * DCT12_3 - src[2] * DCT12_2 - src[3] * DCT12_5 + src[5] * DCT12_4 - t1;
-    dst[ 6] = -src[0] * DCT12_4 + src[2] * DCT12_5 - src[3] * DCT12_2 + src[5] * DCT12_3 - t0;
-    dst[ 8] = -src[0] * DCT12_5 - src[2] * DCT12_4 + src[3] * DCT12_3 + src[5] * DCT12_2 + t1;
+    dst[ 3] =  src[0] * DCT12_2 + src[6] * DCT12_3 + src[9] * DCT12_4 + src[15] * DCT12_5 - t0;
+    dst[ 5] =  src[0] * DCT12_3 - src[6] * DCT12_2 - src[9] * DCT12_5 + src[15] * DCT12_4 - t1;
+    dst[ 6] = -src[0] * DCT12_4 + src[6] * DCT12_5 - src[9] * DCT12_2 + src[15] * DCT12_3 - t0;
+    dst[ 8] = -src[0] * DCT12_5 - src[6] * DCT12_4 + src[9] * DCT12_3 + src[15] * DCT12_2 + t1;
     dst[ 2] = -dst[3];
     dst[ 0] = -dst[5];
     dst[11] =  dst[6];