X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=libavcodec%2Fra144.c;h=95d9e70cbdd380a61e0de6e4101f2981c5f6f570;hb=2d73e6c8d7fe460877760ee295fcbe1f64a308b8;hp=c820c732baa6915d413ead601a19d2aa82efe230;hpb=aee481cebe8f95ce3789bdead6fb8ddfb142c37f;p=ffmpeg

diff --git a/libavcodec/ra144.c b/libavcodec/ra144.c
index c820c732baa..95d9e70cbdd 100644
--- a/libavcodec/ra144.c
+++ b/libavcodec/ra144.c
@@ -20,13 +20,9 @@
  */
 
 #include "avcodec.h"
+#include "bitstream.h"
 #include "ra144.h"
 
-#define DATABLOCK1      20      /* size of 14.4 input block in bytes */
-#define DATACHUNK1      1440    /* size of 14.4 input chunk in bytes */
-#define AUDIOBLOCK      160     /* size of output block in 16-bit words (320 bytes) */
-#define AUDIOBUFFER     12288   /* size of output buffer in 16-bit words (24576 bytes) */
-/* consts */
 #define NBLOCKS         4       /* number of segments within a block */
 #define BLOCKSIZE       40      /* (quarter) block size in 16-bit words (80 bytes) */
 #define HALFBLOCK       20      /* BLOCKSIZE/2 */
@@ -35,472 +31,359 @@
 
 /* internal globals */
 typedef struct {
-        unsigned int     resetflag, val, oldval;
-        unsigned int     unpacked[28];          /* buffer for unpacked input */
-        unsigned int    *iptr;                  /* pointer to current input (from unpacked) */
-        unsigned int     gval;
-        unsigned short  *gsp;
-        unsigned int     gbuf1[8];
-        unsigned short   gbuf2[120];
-        signed   short   output_buffer[40];
-        unsigned int    *decptr;                /* decoder ptr */
-        signed   short  *decsp;
-
-        /* the swapped buffers */
-        unsigned int     swapb1a[10];
-        unsigned int     swapb2a[10];
-        unsigned int     swapb1b[10];
-        unsigned int     swapb2b[10];
-        unsigned int    *swapbuf1;
-        unsigned int    *swapbuf2;
-        unsigned int    *swapbuf1alt;
-        unsigned int    *swapbuf2alt;
-
-        unsigned int buffer[5];
-        unsigned short int buffer_2[148];
-        unsigned short int buffer_a[40];
-        unsigned short int buffer_b[40];
-        unsigned short int buffer_c[40];
-        unsigned short int buffer_d[40];
-
-        unsigned short int work[50];
-        unsigned short *sptr;
-
-        int buffer1[10];
-        int buffer2[10];
-
-        signed short wavtable1[2304];
-        unsigned short wavtable2[2304];
-} Real144_internal;
+    unsigned int     old_energy;        ///< previous frame energy
+
+    /* the swapped buffers */
+    unsigned int     lpc_tables[4][10];
+    unsigned int    *lpc_refl;          ///< LPC reflection coefficients
+    unsigned int    *lpc_coef;          ///< LPC coefficients
+    unsigned int    *lpc_refl_old;      ///< previous frame LPC reflection coefs
+    unsigned int    *lpc_coef_old;      ///< previous frame LPC coefficients
+
+    unsigned int buffer[5];
+    uint16_t adapt_cb[148];             ///< adaptive codebook
+} RA144Context;
 
 static int ra144_decode_init(AVCodecContext * avctx)
 {
-        Real144_internal *glob=avctx->priv_data;
-
-        memset(glob,0,sizeof(Real144_internal));
-        glob->resetflag=1;
-        glob->swapbuf1=glob->swapb1a;
-        glob->swapbuf2=glob->swapb2a;
-        glob->swapbuf1alt=glob->swapb1b;
-        glob->swapbuf2alt=glob->swapb2b;
+    RA144Context *ractx = avctx->priv_data;
 
-        memcpy(glob->wavtable1,wavtable1,sizeof(wavtable1));
-        memcpy(glob->wavtable2,wavtable2,sizeof(wavtable2));
+    ractx->lpc_refl     = ractx->lpc_tables[0];
+    ractx->lpc_coef     = ractx->lpc_tables[1];
+    ractx->lpc_refl_old = ractx->lpc_tables[2];
+    ractx->lpc_coef_old = ractx->lpc_tables[3];
 
-        return 0;
+    return 0;
 }
 
-static void final(Real144_internal *glob, short *i1, short *i2, void *out, int *statbuf, int len);
-static void add_wav(Real144_internal *glob, int n, int f, int m1, int m2, int m3, short *s1, short *s2, short *s3, short *dest);
-static int irms(short *data, int factor);
-static void rotate_block(short *source, short *target, int offset);
-/* lookup square roots in table */
+/**
+ * Evaluate sqrt(x << 24). x must fit in 20 bits. This value is evaluated in an
+ * odd way to make the output identical to the binary decoder.
+ */
 static int t_sqrt(unsigned int x)
 {
-  int s=0;
-  while (x>0xfff) { s++; x=x>>2; }
-  return (sqrt_table[x]<<s)<<2;
+    int s = 0;
+    while (x > 0xfff) {
+        s++;
+        x = x >> 2;
+    }
+
+    return (ff_sqrt(x << 20) << s) << 2;
 }
 
-/* do 'voice' */
-static void do_voice(int *a1, int *a2)
+/**
+ * Evaluate the LPC filter coefficients from the reflection coefficients.
+ * Does the inverse of the eval_refl() function.
+ */
+static void eval_coefs(const int *refl, int *coefs)
 {
-  int buffer[10];
-  int *b1,*b2;
-  int x,y;
-  int *ptr,*tmp;
+    int buffer[10];
+    int *b1 = buffer;
+    int *b2 = coefs;
+    int x, y;
 
-  b1=buffer;
-  b2=a2;
+    for (x=0; x < 10; x++) {
+        b1[x] = refl[x] << 4;
 
-  for (x=0;x<10;x++) {
-    b1[x]=(*a1)<<4;
+        for (y=0; y < x; y++)
+            b1[y] = ((refl[x] * b2[x-y-1]) >> 12) + b2[y];
 
-    if(x>0) {
-      ptr=b2+x;
-      for (y=0;y<=x-1;y++)
-        b1[y]=(((*a1)*(*(--ptr)))>>12)+b2[y];
+        FFSWAP(int *, b1, b2);
     }
-    tmp=b1;
-    b1=b2;
-    b2=tmp;
-    a1++;
-  }
-  ptr=a2+10;
-  while (ptr>a2) (*a2++)>>=4;
-}
 
-
-/* do quarter-block output */
-static void do_output_subblock(Real144_internal *glob, unsigned int x)
-{
-  int a,b,c,d,e,f,g;
-
-  if (x==1) memset(glob->buffer,0,20);
-  if ((*glob->iptr)==0) a=0;
-  else a=(*glob->iptr)+HALFBLOCK-1;
-  glob->iptr++;
-  b=*(glob->iptr++);
-  c=*(glob->iptr++);
-  d=*(glob->iptr++);
-  if (a) rotate_block(glob->buffer_2,glob->buffer_a,a);
-  memcpy(glob->buffer_b,etable1+b*BLOCKSIZE,BLOCKSIZE*2);
-  e=((ftable1[b]>>4)*glob->gval)>>8;
-  memcpy(glob->buffer_c,etable2+c*BLOCKSIZE,BLOCKSIZE*2);
-  f=((ftable2[c]>>4)*glob->gval)>>8;
-  if (a) g=irms(glob->buffer_a,glob->gval)>>12;
-  else g=0;
-  add_wav(glob,d,a,g,e,f,glob->buffer_a,glob->buffer_b,glob->buffer_c,glob->buffer_d);
-  memmove(glob->buffer_2,glob->buffer_2+BLOCKSIZE,(BUFFERSIZE-BLOCKSIZE)*2);
-  memcpy(glob->buffer_2+BUFFERSIZE-BLOCKSIZE,glob->buffer_d,BLOCKSIZE*2);
-  final(glob,glob->gsp,glob->buffer_d,glob->output_buffer,glob->buffer,BLOCKSIZE);
+    for (x=0; x < 10; x++)
+        coefs[x] >>= 4;
 }
 
 /* rotate block */
-static void rotate_block(short *source, short *target, int offset)
+static void rotate_block(const int16_t *source, int16_t *target, int offset)
 {
-  short *end;
-  short *ptr1;
-  short *ptr2;
-  short *ptr3;
-  ptr2=source+BUFFERSIZE;
-  ptr3=ptr1=ptr2-offset;
-  end=target+BLOCKSIZE;
-  while (target<end) {
-    *(target++)=*(ptr3++);
-    if (ptr3==ptr2) ptr3=ptr1;
-  }
+    int i=0, k=0;
+    source += BUFFERSIZE - offset;
+
+    while (i<BLOCKSIZE) {
+        target[i++] = source[k++];
+
+        if (k == offset)
+            k = 0;
+    }
 }
 
 /* inverse root mean square */
-static int irms(short *data, int factor)
+static int irms(const int16_t *data, int factor)
 {
-  short *p1,*p2;
-  unsigned int sum;
-  p2=(p1=data)+BLOCKSIZE;
-  for (sum=0;p2>p1;p1++) sum+=(*p1)*(*p1);
-  if (sum==0) return 0; /* OOPS - division by zero */
-  return (0x20000000/(t_sqrt(sum)>>8))*factor;
+    unsigned int i, sum = 0;
+
+    for (i=0; i < BLOCKSIZE; i++)
+        sum += data[i] * data[i];
+
+    if (sum == 0)
+        return 0; /* OOPS - division by zero */
+
+    return (0x20000000 / (t_sqrt(sum) >> 8)) * factor;
 }
 
 /* multiply/add wavetable */
-static void add_wav(Real144_internal *glob, int n, int f, int m1, int m2, int m3, short *s1, short *s2, short *s3, short *dest)
+static void add_wav(int n, int skip_first, int *m, const int16_t *s1,
+                    const int8_t *s2, const int8_t *s3, int16_t *dest)
 {
-  int a,b,c;
-  short *ptr,*ptr2;
-
-  ptr=glob->wavtable1+n*9;
-  ptr2=glob->wavtable2+n*9;
-  if (f!=0) {
-    a=((*ptr)*m1)>>((*ptr2)+1);
-  } else {
-    a=0;
-  }
-  ptr++;ptr2++;
-  b=((*ptr)*m2)>>((*ptr2)+1);
-  ptr++;ptr2++;
-  c=((*ptr)*m3)>>((*ptr2)+1);
-  ptr2=(ptr=dest)+BLOCKSIZE;
-  if (f!=0)
-    while (ptr<ptr2)
-      *(ptr++)=((*(s1++))*a+(*(s2++))*b+(*(s3++))*c)>>12;
-  else
-    while (ptr<ptr2)
-      *(ptr++)=((*(s2++))*b+(*(s3++))*c)>>12;
+    int i;
+    int v[3];
+
+    v[0] = 0;
+    for (i=!skip_first; i<3; i++)
+        v[i] = (wavtable1[n][i] * m[i]) >> (wavtable2[n][i] + 1);
+
+    for (i=0; i < BLOCKSIZE; i++)
+        dest[i] = ((*(s1++))*v[0] + (*(s2++))*v[1] + (*(s3++))*v[2]) >> 12;
 }
 
 
-static void final(Real144_internal *glob, short *i1, short *i2, void *out, int *statbuf, int len)
+static void final(const int16_t *i1, const int16_t *i2,
+                  void *out, int *statbuf, int len)
 {
-  int x,sum;
-  int buffer[10];
-  short *ptr;
-  short *ptr2;
-
-  memcpy(glob->work,statbuf,20);
-  memcpy(glob->work+10,i2,len*2);
-
-  buffer[9]=i1[0];
-  buffer[8]=i1[1];
-  buffer[7]=i1[2];
-  buffer[6]=i1[3];
-  buffer[5]=i1[4];
-  buffer[4]=i1[5];
-  buffer[3]=i1[6];
-  buffer[2]=i1[7];
-  buffer[1]=i1[8];
-  buffer[0]=i1[9];
-
-  ptr2=(ptr=glob->work)+len;
-  while (ptr<ptr2) {
-    for(sum=0,x=0;x<=9;x++)
-      sum+=buffer[x]*(ptr[x]);
-    sum=sum>>12;
-    x=ptr[10]-sum;
-    if (x<-32768 || x>32767)
-    {
-      memset(out,0,len*2);
-      memset(statbuf,0,20);
-      return;
+    int x, i;
+    uint16_t work[50];
+    int16_t *ptr = work;
+
+    memcpy(work, statbuf,20);
+    memcpy(work + 10, i2, len * 2);
+
+    for (i=0; i<len; i++) {
+        int sum = 0;
+        int new_val;
+
+        for(x=0; x<10; x++)
+            sum += i1[9-x] * ptr[x];
+
+        sum >>= 12;
+
+        new_val = ptr[10] - sum;
+
+        if (new_val < -32768 || new_val > 32767) {
+            memset(out, 0, len * 2);
+            memset(statbuf, 0, 20);
+            return;
+        }
+
+        ptr[10] = new_val;
+        ptr++;
     }
-    ptr[10]=x;
-    ptr++;
-  }
-  memcpy(out,ptr+10-len,len*2);
-  memcpy(statbuf,ptr,20);
+
+    memcpy(out, work+10, len * 2);
+    memcpy(statbuf, work + 40, 20);
 }
 
-/* Decode 20-byte input */
-static void unpack_input(unsigned char *input, unsigned int *output)
+static unsigned int rms(const int *data, int f, RA144Context *ractx)
 {
-  unsigned int outbuffer[28];
-  unsigned short inbuffer[10];
-  unsigned int x;
-  unsigned int *ptr;
-
-  /* fix endianness */
-  for (x=0;x<20;x+=2)
-    inbuffer[x/2]=(input[x]<<8)+input[x+1];
-
-  /* unpack */
-  ptr=outbuffer;
-  *(ptr++)=27;
-  *(ptr++)=(inbuffer[0]>>10)&0x3f;
-  *(ptr++)=(inbuffer[0]>>5)&0x1f;
-  *(ptr++)=inbuffer[0]&0x1f;
-  *(ptr++)=(inbuffer[1]>>12)&0xf;
-  *(ptr++)=(inbuffer[1]>>8)&0xf;
-  *(ptr++)=(inbuffer[1]>>5)&7;
-  *(ptr++)=(inbuffer[1]>>2)&7;
-  *(ptr++)=((inbuffer[1]<<1)&6)|((inbuffer[2]>>15)&1);
-  *(ptr++)=(inbuffer[2]>>12)&7;
-  *(ptr++)=(inbuffer[2]>>10)&3;
-  *(ptr++)=(inbuffer[2]>>5)&0x1f;
-  *(ptr++)=((inbuffer[2]<<2)&0x7c)|((inbuffer[3]>>14)&3);
-  *(ptr++)=(inbuffer[3]>>6)&0xff;
-  *(ptr++)=((inbuffer[3]<<1)&0x7e)|((inbuffer[4]>>15)&1);
-  *(ptr++)=(inbuffer[4]>>8)&0x7f;
-  *(ptr++)=(inbuffer[4]>>1)&0x7f;
-  *(ptr++)=((inbuffer[4]<<7)&0x80)|((inbuffer[5]>>9)&0x7f);
-  *(ptr++)=(inbuffer[5]>>2)&0x7f;
-  *(ptr++)=((inbuffer[5]<<5)&0x60)|((inbuffer[6]>>11)&0x1f);
-  *(ptr++)=(inbuffer[6]>>4)&0x7f;
-  *(ptr++)=((inbuffer[6]<<4)&0xf0)|((inbuffer[7]>>12)&0xf);
-  *(ptr++)=(inbuffer[7]>>5)&0x7f;
-  *(ptr++)=((inbuffer[7]<<2)&0x7c)|((inbuffer[8]>>14)&3);
-  *(ptr++)=(inbuffer[8]>>7)&0x7f;
-  *(ptr++)=((inbuffer[8]<<1)&0xfe)|((inbuffer[9]>>15)&1);
-  *(ptr++)=(inbuffer[9]>>8)&0x7f;
-  *(ptr++)=(inbuffer[9]>>1)&0x7f;
-
-  *(output++)=outbuffer[11];
-  for (x=1;x<11;*(output++)=outbuffer[x++]);
-  ptr=outbuffer+12;
-  for (x=0;x<16;x+=4)
-  {
-    *(output++)=ptr[x];
-    *(output++)=ptr[x+2];
-    *(output++)=ptr[x+3];
-    *(output++)=ptr[x+1];
-  }
+    int x;
+    unsigned int res = 0x10000;
+    int b = 0;
+
+    for (x=0; x<10; x++) {
+        res = (((0x1000000 - (*data) * (*data)) >> 12) * res) >> 12;
+
+        if (res == 0)
+            return 0;
+
+        if (res > 0x10000) {
+            av_log(ractx, AV_LOG_ERROR, "Overflow. Broken sample?\n");
+            return 0;
+        }
+
+        while (res <= 0x3fff) {
+            b++;
+            res <<= 2;
+        }
+        data++;
+    }
+
+    if (res > 0)
+        res = t_sqrt(res);
+
+    res >>= (b + 10);
+    res = (res * f) >> 10;
+    return res;
 }
 
-static unsigned int rms(int *data, int f)
+/* do quarter-block output */
+static void do_output_subblock(RA144Context *ractx,
+                               const uint16_t  *lpc_coefs, unsigned int gval,
+                               int16_t *output_buffer, GetBitContext *gb)
 {
-  int *c;
-  int x;
-  unsigned int res;
-  int b;
-
-  c=data;
-  b=0;
-  res=0x10000;
-  for (x=0;x<10;x++)
-  {
-    res=(((0x1000000-(*c)*(*c))>>12)*res)>>12;
-    if (res==0) return 0;
-    if (res<=0x3fff)
-    {
-      while (res<=0x3fff)
-      {
-        b++;
-        res<<=2;
-      }
+    uint16_t buffer_a[40];
+    uint16_t *block;
+    int cba_idx = get_bits(gb, 7); // index of the adaptive CB, 0 if none
+    int gain    = get_bits(gb, 8);
+    int cb1_idx = get_bits(gb, 7);
+    int cb2_idx = get_bits(gb, 7);
+    int m[3];
+
+    if (cba_idx) {
+        cba_idx += HALFBLOCK - 1;
+        rotate_block(ractx->adapt_cb, buffer_a, cba_idx);
+        m[0] = irms(buffer_a, gval) >> 12;
     } else {
-      if (res>0x10000)
-        return 0; /* We're screwed, might as well go out with a bang. :P */
+        m[0] = 0;
     }
-    c++;
-  }
-  if (res>0) res=t_sqrt(res);
 
-  res>>=(b+10);
-  res=(res*f)>>10;
-  return res;
+    m[1] = ((ftable1[cb1_idx] >> 4) * gval) >> 8;
+    m[2] = ((ftable2[cb2_idx] >> 4) * gval) >> 8;
+
+    memmove(ractx->adapt_cb, ractx->adapt_cb + BLOCKSIZE,
+            (BUFFERSIZE - BLOCKSIZE) * 2);
+
+    block = ractx->adapt_cb + BUFFERSIZE - BLOCKSIZE;
+
+    add_wav(gain, cba_idx, m, buffer_a, etable1[cb1_idx], etable2[cb2_idx],
+            block);
+
+    final(lpc_coefs, block, output_buffer, ractx->buffer, BLOCKSIZE);
 }
 
-static void dec1(Real144_internal *glob, int *data, int *inp, int n, int f)
+static void int_to_int16(int16_t *decsp, const int *inp)
 {
-  short *ptr,*end;
+    int i;
 
-  *(glob->decptr++)=rms(data,f);
-  glob->decptr++;
-  end=(ptr=glob->decsp)+(n*10);
-  while (ptr<end) *(ptr++)=*(inp++);
+    for (i=0; i<30; i++)
+        *(decsp++) = *(inp++);
 }
 
-static int eq(Real144_internal *glob, short *in, int *target)
+/**
+ * Evaluate the reflection coefficients from the filter coefficients.
+ * Does the inverse of the eval_coefs() function.
+ *
+ * @return 1 if one of the reflection coefficients is of magnitude greater than
+ *         4095, 0 if not.
+ */
+static int eval_refl(const int16_t *coefs, int *refl, RA144Context *ractx)
 {
-  int retval;
-  int a;
-  int b;
-  int c;
-  unsigned int u;
-  short *sptr;
-  int *ptr1,*ptr2,*ptr3;
-  int *bp1,*bp2,*temp;
-
-  retval=0;
-  bp1=glob->buffer1;
-  bp2=glob->buffer2;
-  ptr2=(ptr3=glob->buffer2)+9;
-  sptr=in;
-  while (ptr2>=ptr3)
-    *(ptr3++)=*(sptr++);
-
-  target+=9;
-  a=bp2[9];
-  *target=a;
-  if (a+0x1000>0x1fff)
-    return 0; /* We're screwed, might as well go out with a bang. :P */
-  c=8;u=a;
-  while (c>=0)
-  {
-    if (u==0x1000) u++;
-    if (u==0xfffff000) u--;
-    b=0x1000-((u*u)>>12);
-    if (b==0) b++;
-    ptr2=bp1;
-    ptr1=(ptr3=bp2)+c;
-    for (u=0;u<=c;u++)
-      *(ptr2++)=((*(ptr3++)-(((*target)*(*(ptr1--)))>>12))*(0x1000000/b))>>12;
-    *(--target)=u=bp1[(c--)];
-    if ((u+0x1000)>0x1fff) retval=1;
-    temp=bp2;
-    bp2=bp1;
-    bp1=temp;
-  }
-  return retval;
+    int retval = 0;
+    int b, c, i;
+    unsigned int u;
+    int buffer1[10];
+    int buffer2[10];
+    int *bp1 = buffer1;
+    int *bp2 = buffer2;
+
+    for (i=0; i < 10; i++)
+        buffer2[i] = coefs[i];
+
+    u = refl[9] = bp2[9];
+
+    if (u + 0x1000 > 0x1fff) {
+        av_log(ractx, AV_LOG_ERROR, "Overflow. Broken sample?\n");
+        return 0;
+    }
+
+    for (c=8; c >= 0; c--) {
+        if (u == 0x1000)
+            u++;
+
+        if (u == 0xfffff000)
+            u--;
+
+        b = 0x1000-((u * u) >> 12);
+
+        if (b == 0)
+            b++;
+
+        for (u=0; u<=c; u++)
+            bp1[u] = ((bp2[u] - ((refl[c+1] * bp2[c-u]) >> 12)) * (0x1000000 / b)) >> 12;
+
+        refl[c] = u = bp1[c];
+
+        if ((u + 0x1000) > 0x1fff)
+            retval = 1;
+
+        FFSWAP(int *, bp1, bp2);
+    }
+    return retval;
 }
 
-static void dec2(Real144_internal *glob, int *data, int *inp, int n, int f, int *inp2, int l)
+static int interp(RA144Context *ractx, int16_t *decsp, int block_num,
+                  int copynew, int energy)
 {
-  unsigned int *ptr1,*ptr2;
-  int work[10];
-  int a,b;
-  int x;
-  int result;
-
-  if(l+1<NBLOCKS/2) a=NBLOCKS-(l+1);
-  else a=l+1;
-  b=NBLOCKS-a;
-  if (l==0)
-  {
-    glob->decsp=glob->sptr=glob->gbuf2;
-    glob->decptr=glob->gbuf1;
-  }
-  ptr1=inp;
-  ptr2=inp2;
-  for (x=0;x<10*n;x++)
-    *(glob->sptr++)=(a*(*ptr1++)+b*(*ptr2++))>>2;
-  result=eq(glob,glob->decsp,work);
-  if (result==1)
-  {
-    dec1(glob,data,inp,n,f);
-  } else {
-    *(glob->decptr++)=rms(work,f);
-    glob->decptr++;
-  }
-  glob->decsp+=n*10;
+    int work[10];
+    int a = block_num + 1;
+    int b = NBLOCKS - a;
+    int x;
+
+    // Interpolate block coefficients from the this frame forth block and
+    // last frame forth block
+    for (x=0; x<30; x++)
+        decsp[x] = (a * ractx->lpc_coef[x] + b * ractx->lpc_coef_old[x])>> 2;
+
+    if (eval_refl(decsp, work, ractx)) {
+        // The interpolated coefficients are unstable, copy either new or old
+        // coefficients
+        if (copynew) {
+            int_to_int16(decsp, ractx->lpc_coef);
+            return rms(ractx->lpc_refl, energy, ractx);
+        } else {
+            int_to_int16(decsp, ractx->lpc_coef_old);
+            return rms(ractx->lpc_refl_old, energy, ractx);
+        }
+    } else {
+        return rms(work, energy, ractx);
+    }
 }
 
 /* Uncompress one block (20 bytes -> 160*2 bytes) */
 static int ra144_decode_frame(AVCodecContext * avctx,
-            void *vdata, int *data_size,
-            uint8_t * buf, int buf_size)
+                              void *vdata, int *data_size,
+                              const uint8_t * buf, int buf_size)
 {
-  unsigned int a,b,c;
-  long s;
-  signed short *shptr;
-  unsigned int *lptr,*temp;
-  const short **dptr;
-  int16_t *datao;
-  int16_t *data = vdata;
-  Real144_internal *glob=avctx->priv_data;
+    static const uint8_t sizes[10] = {6, 5, 5, 4, 4, 3, 3, 3, 3, 2};
+    unsigned int refl_rms[4];  // RMS of the reflection coefficients
+    uint16_t block_coefs[4][30]; // LPC coefficients of each sub-block
+    int i, c;
+    int16_t *data = vdata;
+    unsigned int energy;
+
+    RA144Context *ractx = avctx->priv_data;
+    GetBitContext gb;
+
+    if(buf_size < 20) {
+        av_log(avctx, AV_LOG_ERROR,
+               "Frame too small (%d bytes). Truncated file?\n", buf_size);
+        return buf_size;
+    }
+    init_get_bits(&gb, buf, 20 * 8);
 
-  if(buf_size==0)
-      return 0;
+    for (i=0; i<10; i++)
+        // "<< 1"? Doesn't this make one value out of two of the table useless?
+        ractx->lpc_refl[i] = decodetable[i][get_bits(&gb, sizes[i]) << 1];
 
-  datao = data;
-  unpack_input(buf,glob->unpacked);
+    eval_coefs(ractx->lpc_refl, ractx->lpc_coef);
 
-  glob->iptr=glob->unpacked;
-  glob->val=decodetable[0][(*(glob->iptr++))<<1];
+    energy = decodeval[get_bits(&gb, 5) << 1]; // Useless table entries?
 
-  dptr=decodetable+1;
-  lptr=glob->swapbuf1;
-  while (lptr<glob->swapbuf1+10)
-    *(lptr++)=(*(dptr++))[(*(glob->iptr++))<<1];
+    refl_rms[0] = interp(ractx, block_coefs[0], 0, 0, ractx->old_energy);
+    refl_rms[1] = interp(ractx, block_coefs[1], 1, energy > ractx->old_energy,
+                    t_sqrt(energy*ractx->old_energy) >> 12);
+    refl_rms[2] = interp(ractx, block_coefs[2], 2, 1, energy);
+    refl_rms[3] = rms(ractx->lpc_refl, energy, ractx);
 
-  do_voice(glob->swapbuf1,glob->swapbuf2);
+    int_to_int16(block_coefs[3], ractx->lpc_coef);
 
-  a=t_sqrt(glob->val*glob->oldval)>>12;
+    /* do output */
+    for (c=0; c<4; c++) {
+        do_output_subblock(ractx, block_coefs[c], refl_rms[c], data, &gb);
 
-  for (c=0;c<NBLOCKS;c++) {
-    if (c==(NBLOCKS-1)) {
-      dec1(glob,glob->swapbuf1,glob->swapbuf2,3,glob->val);
-    } else {
-      if (c*2==(NBLOCKS-2)) {
-        if (glob->oldval<glob->val) {
-          dec2(glob,glob->swapbuf1,glob->swapbuf2,3,a,glob->swapbuf2alt,c);
-        } else {
-          dec2(glob,glob->swapbuf1alt,glob->swapbuf2alt,3,a,glob->swapbuf2,c);
-        }
-      } else {
-        if (c*2<(NBLOCKS-2)) {
-          dec2(glob,glob->swapbuf1alt,glob->swapbuf2alt,3,glob->oldval,glob->swapbuf2,c);
-        } else {
-          dec2(glob,glob->swapbuf1,glob->swapbuf2,3,glob->val,glob->swapbuf2alt,c);
+        for (i=0; i<BLOCKSIZE; i++) {
+            *data = av_clip_int16(*data << 2);
+            data++;
         }
-      }
     }
-  }
-
-  /* do output */
-  for (b=0,c=0;c<4;c++) {
-    glob->gval=glob->gbuf1[c*2];
-    glob->gsp=glob->gbuf2+b;
-    do_output_subblock(glob,glob->resetflag);
-    glob->resetflag=0;
-
-    shptr=glob->output_buffer;
-    while (shptr<glob->output_buffer+BLOCKSIZE) {
-      s=*(shptr++)<<2;
-      *data=av_clip_int16(s);
-      data++;
-    }
-    b+=30;
-  }
-
-  glob->oldval=glob->val;
-  temp=glob->swapbuf1alt;
-  glob->swapbuf1alt=glob->swapbuf1;
-  glob->swapbuf1=temp;
-  temp=glob->swapbuf2alt;
-  glob->swapbuf2alt=glob->swapbuf2;
-  glob->swapbuf2=temp;
-  *data_size=(data-datao)*sizeof(*data);
-  return 20;
+
+    ractx->old_energy = energy;
+
+    FFSWAP(unsigned int *, ractx->lpc_refl_old, ractx->lpc_refl);
+    FFSWAP(unsigned int *, ractx->lpc_coef_old, ractx->lpc_coef);
+
+    *data_size = 2*160;
+    return 20;
 }
 
 
@@ -509,9 +392,10 @@ AVCodec ra_144_decoder =
     "real_144",
     CODEC_TYPE_AUDIO,
     CODEC_ID_RA_144,
-    sizeof(Real144_internal),
+    sizeof(RA144Context),
     ra144_decode_init,
     NULL,
     NULL,
     ra144_decode_frame,
+    .long_name = "RealAudio 1.0 (14.4K)",
 };