audio/mp3: Move Decode_L3 to Go

audio/mp3/decode_notjs.go

@@ -17,11 +17,14 @@
 package mp3
 
 // #include "pdmp3.h"
+//
+// //extern t_mpeg1_main_data g_main_data;
+// extern t_mpeg1_header    g_frame_header;
+// //extern t_mpeg1_side_info g_side_info;
 import "C"
 
 import (
 	"io"
-	"unsafe"
 )
 
 const (
@@ -36,6 +39,57 @@ var (
 	writer      io.Writer
 )
 
+func decodeL3() error {
+	out := make([]int, 576)
+	/* Number of channels(1 for mono and 2 for stereo) */
+	nch := 2
+	if C.g_frame_header.mode == C.mpeg1_mode_single_channel {
+		nch = 1
+	}
+	for gr := 0; gr < 2; gr++ {
+		for ch := 0; ch < nch; ch++ {
+			L3_Requantize(C.uint(gr), C.uint(ch)) /* Requantize samples */
+			L3_Reorder(C.uint(gr), C.uint(ch))    /* Reorder short blocks */
+		}
+		L3_Stereo(C.uint(gr)) /* Stereo processing */
+		for ch := 0; ch < nch; ch++ {
+			L3_Antialias(C.uint(gr), C.uint(ch))
+			// (IMDCT,windowing,overlapp add)
+			L3_Hybrid_Synthesis(C.uint(gr), C.uint(ch))
+			L3_Frequency_Inversion(C.uint(gr), C.uint(ch))
+			// Polyphase subband synthesis
+			l3SubbandSynthesis(gr, ch, out)
+		}
+		if err := audioWriteRaw(out); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func audioWriteRaw(samples []int) error {
+	nch := 2
+	if C.g_frame_header.mode == C.mpeg1_mode_single_channel {
+		nch = 1
+	}
+	s := make([]uint8, len(samples)*2*nch)
+	for i, v := range samples {
+		if nch == 1 {
+			s[2*i] = uint8(v)
+			s[2*i+1] = uint8(v >> 8)
+		} else {
+			s[4*i] = uint8(v)
+			s[4*i+1] = uint8(v >> 8)
+			s[4*i+2] = uint8(v >> 16)
+			s[4*i+3] = uint8(v >> 24)
+		}
+	}
+	if _, err := writer.Write(s); err != nil {
+		return err
+	}
+	return nil
+}
+
 func getByte() (uint8, error) {
 	for len(readerCache) == 0 && !readerEOF {
 		buf := make([]uint8, 4096)
@@ -77,23 +131,16 @@ func Get_Filepos() C.unsigned {
 	return C.unsigned(readerPos)
 }
 
-//export writeToWriter
-func writeToWriter(data unsafe.Pointer, size C.int) C.size_t {
-	buf := C.GoBytes(data, size)
-	n, err := writer.Write(buf)
-	if err != nil {
-		panic(err)
-	}
-	return C.size_t(n)
-}
-
 func decode(r io.Reader, w io.Writer) error {
+	// TODO: Decoder should know number of channels
 	reader = r
 	writer = w
 	for Get_Filepos() != eof {
 		err := readFrame()
 		if err == nil {
-			C.Decode_L3()
+			if err := decodeL3(); err != nil {
+				return err
+			}
 			continue
 		}
 		if Get_Filepos() == eof {

audio/mp3/l3.go

@@ -25,7 +25,6 @@ import "C"
 
 import (
 	"math"
-	"unsafe"
 )
 
 var (
@@ -565,13 +564,7 @@ var g_synth_dtbl = [512]float32{
 	0.000015259, 0.000015259, 0.000015259, 0.000015259,
 }
 
-//export L3_Subband_Synthesis
+func l3SubbandSynthesis(gr int, ch int, out []int) {
-func L3_Subband_Synthesis(gr C.unsigned, ch C.unsigned, outdata *C.unsigned) {
-	out := make([]C.unsigned, 576)
-	for i := range out {
-		out[i] = *(*C.unsigned)(unsafe.Pointer(uintptr(unsafe.Pointer(outdata)) + uintptr(i)*unsafe.Sizeof(*outdata)))
-	}
-
 	u_vec := make([]float32, 512)
 	s_vec := make([]float32, 32)
 
@@ -620,16 +613,13 @@ func L3_Subband_Synthesis(gr C.unsigned, ch C.unsigned, outdata *C.unsigned) {
 			if ch == 0 { /* This function must be called for channel 0 first */
 				/* We always run in stereo mode,& duplicate channels here for mono */
 				if nch == 1 {
-					out[32*ss+i] = C.unsigned((samp << 16) | (samp))
+					out[32*ss+i] = (samp << 16) | (samp)
 				} else {
-					out[32*ss+i] = C.unsigned(samp << 16)
+					out[32*ss+i] = samp << 16
 				}
 			} else {
-				out[32*ss+i] |= C.unsigned(samp)
+				out[32*ss+i] |= samp
 			}
 		}
 	}
-	for i := range out {
-		*(*C.unsigned)(unsafe.Pointer(uintptr(unsafe.Pointer(outdata)) + uintptr(i)*unsafe.Sizeof(*outdata))) = out[i]
-	}
 }

audio/mp3/pdmp3.c

@@ -41,9 +41,7 @@ static void dmp_samples(t_mpeg1_main_data *md,int gr,int ch,int type);
 
 static void audio_write(unsigned *samples,unsigned nsamples,int sample_rate);
 static void audio_write_raw(unsigned *samples,unsigned nsamples);
-static void Decode_L3_Init_Song(void);
 static void Error(const char *s,int e);
-static void Read_Ancillary(void);
 
 static const unsigned g_mpeg1_bitrates[3 /* layer 1-3 */][15 /* header bitrate_index */] = {
   {    /* Layer 1 */
@@ -159,51 +157,6 @@ static void dmp_samples(t_mpeg1_main_data *md,int gr,int ch,int type){
 }
 #endif
 
-/**Description: decodes a layer 3 bitstream into audio samples.
-* Parameters: Outdata vector.
-* Return value: OK or ERROR if the frame contains errors.
-* Author: Krister Lagerström(krister@kmlager.com) **/
-int Decode_L3(void){
-  unsigned gr,ch,nch,out[576];
-
-  /* Number of channels(1 for mono and 2 for stereo) */
-  nch =(g_frame_header.mode == mpeg1_mode_single_channel ? 1 : 2);
-  for(gr = 0; gr < 2; gr++) {
-    for(ch = 0; ch < nch; ch++) {
-      dmp_scf(&g_side_info,&g_main_data,gr,ch); //noop unless debug
-      dmp_huff(&g_main_data,gr,ch); //noop unless debug
-      L3_Requantize(gr,ch); /* Requantize samples */
-      dmp_samples(&g_main_data,gr,ch,0); //noop unless debug
-      L3_Reorder(gr,ch); /* Reorder short blocks */
-    } /* end for(ch... */
-    L3_Stereo(gr); /* Stereo processing */
-    dmp_samples(&g_main_data,gr,0,1); //noop unless debug
-    dmp_samples(&g_main_data,gr,1,1); //noop unless debug
-    for(ch = 0; ch < nch; ch++) {
-      L3_Antialias(gr,ch); /* Antialias */
-      dmp_samples(&g_main_data,gr,ch,2); //noop unless debug
-      L3_Hybrid_Synthesis(gr,ch); /*(IMDCT,windowing,overlapp add) */
-      L3_Frequency_Inversion(gr,ch); /* Frequency inversion */
-     dmp_samples(&g_main_data,gr,ch,3); //noop unless debug
-      L3_Subband_Synthesis(gr,ch,out); /* Polyphase subband synthesis */
-    } /* end for(ch... */
-#ifdef DEBUG
-    {
-      int i,ctr = 0;
-      printf("PCM:\n");
-      for(i = 0; i < 576; i++) {
-        printf("%d: %d\n",ctr++,(out[i] >> 16) & 0xffff);
-        if(nch == 2) printf("%d: %d\n",ctr++,out[i] & 0xffff);
-      }
-    }
-#endif /* DEBUG */
-     /*FIXME - replace with simple interface stream*/
-    audio_write((unsigned *) out,576,
-                 g_sampling_frequency[g_frame_header.sampling_frequency]);
-  } /* end for(gr... */
-  return(OK);   /* Done */
-}
-
 /**Description: TBD
 * Parameters: TBD
 * Return value: TBD
@@ -212,52 +165,3 @@ static void Error(const char *s,int e){
   (void) fwrite(s,1,strlen(s),stderr);
   exit(e);
 }
-
-/**Description: output audio data
-* Parameters: Pointers to the samples,the number of samples
-* Return value: None
-* Author: Krister Lagerström(krister@kmlager.com) **/
-static void audio_write(unsigned *samples,unsigned nsamples,int sample_rate){
-  static int init = 0,audio,curr_sample_rate = 0;
-  int tmp,dsp_speed = 44100,dsp_stereo = 2;
-
-#ifdef OUTPUT_RAW
-  audio_write_raw(samples,nsamples);
-#endif /* OUTPUT_RAW */
-  return;
-} /* audio_write() */
-
-/******************************************************************************
-*
-* Name: audio_write_raw
-* Author: Krister Lagerström(krister@unidata.se)
-* Description: This function is used to output raw data
-* Parameters: Pointers to the samples,the number of samples
-* Return value: None
-* Revision History:
-* Author   Date    Change
-* krister  010101  Initial revision
-*
-******************************************************************************/
-static void audio_write_raw(unsigned *samples,unsigned nsamples){
-  char fname[1024];
-  unsigned lo,hi;
-  int i,nch;
-  unsigned short s[576*2];
-
-  nch =(g_frame_header.mode == mpeg1_mode_single_channel ? 1 : 2);
-  for(i = 0; i < nsamples; i++) {
-    if(nch == 1) {
-      lo = samples[i] & 0xffff;
-      s[i] = lo;
-    }else{
-      lo = samples[i] & 0xffff;
-      hi =(samples[i] & 0xffff0000) >> 16;
-      s[2*i] = hi;
-      s[2*i+1] = lo;
-    }
-  }
-  if(writeToWriter((char *) s,nsamples * 2 * nch) != nsamples * 2 * nch)
-    Error("Unable to write raw data\n",-1);
-  return;
-} /* audio_write_raw() */

audio/mp3/pdmp3.h

@@ -85,21 +85,16 @@ typedef struct { /* Scale factor band indices,for long and short windows */
 t_sf_band_indices;
 
 unsigned Get_Filepos(void);
-int Decode_L3(void);
-size_t writeToWriter(void* data, int size);
 
 unsigned Get_Main_Pos(void);
 int Set_Main_Pos(unsigned bit_pos);
 
-int Read_Audio_L3(void);
-
 void L3_Requantize(unsigned gr,unsigned ch);
 void L3_Reorder(unsigned gr,unsigned ch);
 void L3_Stereo(unsigned gr);
 void L3_Antialias(unsigned gr,unsigned ch);
 void L3_Hybrid_Synthesis(unsigned gr,unsigned ch);
 void L3_Frequency_Inversion(unsigned gr,unsigned ch);
-void L3_Subband_Synthesis(unsigned gr,unsigned ch, unsigned* outdata);
 
 int Read_CRC(void);