overread AV_LOG_ERROR -> AV_LOG_DEBUG
[libav.git] / libavcodec / mpegaudiodec.c
index 562978c..f3e19d7 100644 (file)
@@ -85,13 +85,13 @@ static always_inline int MULH(int a, int b){
 
 #define HEADER_SIZE 4
 #define BACKSTEP_SIZE 512
+#define EXTRABYTES 24
 
 struct GranuleDef;
 
 typedef struct MPADecodeContext {
-    uint8_t inbuf1[2][MPA_MAX_CODED_FRAME_SIZE + BACKSTEP_SIZE];        /* input buffer */
-    int inbuf_index;
-    uint8_t *inbuf_ptr, *inbuf;
+    DECLARE_ALIGNED_8(uint8_t, last_buf[BACKSTEP_SIZE + EXTRABYTES + MPA_MAX_CODED_FRAME_SIZE]); //FIXME we dont need that much
+    int last_buf_size;
     int frame_size;
     int free_format_frame_size; /* frame size in case of free format
                                    (zero if currently unknown) */
@@ -102,8 +102,8 @@ typedef struct MPADecodeContext {
     int sample_rate;
     int sample_rate_index; /* between 0 and 8 */
     int bit_rate;
-    int old_frame_size;
     GetBitContext gb;
+    GetBitContext in_gb;
     int nb_channels;
     int mode;
     int mode_ext;
@@ -173,6 +173,8 @@ static uint16_t band_index_long[9][23];
 #define TABLE_4_3_SIZE (8191 + 16)*4
 static int8_t  *table_4_3_exp;
 static uint32_t *table_4_3_value;
+static uint32_t exp_table[512];
+static uint32_t expval_table[512][16];
 /* intensity stereo coef table */
 static int32_t is_table[2][16];
 static int32_t is_table_lsf[2][2][16];
@@ -371,8 +373,8 @@ static int decode_init(AVCodecContext * avctx)
             const HuffTable *h = &mpa_huff_tables[i];
             int xsize, x, y;
             unsigned int n;
-            uint8_t tmp_bits [256];
-            uint16_t tmp_codes[256];
+            uint8_t  tmp_bits [512];
+            uint16_t tmp_codes[512];
 
             memset(tmp_bits , 0, sizeof(tmp_bits ));
             memset(tmp_codes, 0, sizeof(tmp_codes));
@@ -383,13 +385,13 @@ static int decode_init(AVCodecContext * avctx)
             j = 0;
             for(x=0;x<xsize;x++) {
                 for(y=0;y<xsize;y++){
-                    tmp_bits [(x << 4) | y]= h->bits [j  ];
-                    tmp_codes[(x << 4) | y]= h->codes[j++];
+                    tmp_bits [(x << 5) | y | ((x&&y)<<4)]= h->bits [j  ];
+                    tmp_codes[(x << 5) | y | ((x&&y)<<4)]= h->codes[j++];
                 }
             }
 
             /* XXX: fail test */
-            init_vlc(&huff_vlc[i], 8, 256,
+            init_vlc(&huff_vlc[i], 7, 512,
                      tmp_bits, 1, 1, tmp_codes, 2, 2, 1);
         }
         for(i=0;i<2;i++) {
@@ -421,13 +423,20 @@ static int decode_init(AVCodecContext * avctx)
             f = pow((double)(i/4), 4.0 / 3.0) * pow(2, (i&3)*0.25);
             fm = frexp(f, &e);
             m = (uint32_t)(fm*(1LL<<31) + 0.5);
-            e+= FRAC_BITS - 31 + 5;
+            e+= FRAC_BITS - 31 + 5 - 100;
 
             /* normalized to FRAC_BITS */
             table_4_3_value[i] = m;
 //            av_log(NULL, AV_LOG_DEBUG, "%d %d %f\n", i, m, pow((double)i, 4.0 / 3.0));
             table_4_3_exp[i] = -e;
         }
+        for(i=0; i<512*16; i++){
+            int exponent= (i>>4);
+            double f= pow(i&15, 4.0 / 3.0) * pow(2, (exponent-400)*0.25 + FRAC_BITS + 5);
+            expval_table[exponent][i&15]= lrintf(f);
+            if((i&15)==1)
+                exp_table[exponent]= lrintf(f);
+        }
 
         for(i=0;i<7;i++) {
             float f;
@@ -526,9 +535,6 @@ static int decode_init(AVCodecContext * avctx)
         init = 1;
     }
 
-    s->inbuf_index = 0;
-    s->inbuf = &s->inbuf1[s->inbuf_index][BACKSTEP_SIZE];
-    s->inbuf_ptr = s->inbuf;
 #ifdef DEBUG
     s->frame_count = 0;
 #endif
@@ -1245,7 +1251,6 @@ static int decode_header(MPADecodeContext *s, uint32_t header)
 int mpa_decode_header(AVCodecContext *avctx, uint32_t head)
 {
     MPADecodeContext s1, *s = &s1;
-    memset( s, 0, sizeof(MPADecodeContext) );
 
     if (ff_mpa_check_header(head) != 0)
         return -1;
@@ -1576,29 +1581,6 @@ static int mp_decode_layer2(MPADecodeContext *s)
     return 3 * 12;
 }
 
-/*
- * Seek back in the stream for backstep bytes (at most 511 bytes)
- */
-static void seek_to_maindata(MPADecodeContext *s, unsigned int backstep)
-{
-    uint8_t *ptr;
-
-    /* compute current position in stream */
-    ptr = (uint8_t *)(s->gb.buffer + (get_bits_count(&s->gb)>>3));
-
-    /* copy old data before current one */
-    ptr -= backstep;
-    memcpy(ptr, s->inbuf1[s->inbuf_index ^ 1] +
-           BACKSTEP_SIZE + s->old_frame_size - backstep, backstep);
-    /* init get bits again */
-    init_get_bits(&s->gb, ptr, (s->frame_size + backstep)*8);
-
-    /* prepare next buffer */
-    s->inbuf_index ^= 1;
-    s->inbuf = &s->inbuf1[s->inbuf_index][BACKSTEP_SIZE];
-    s->old_frame_size = s->frame_size;
-}
-
 static inline void lsf_sf_expand(int *slen,
                                  int sf, int n1, int n2, int n3)
 {
@@ -1634,7 +1616,7 @@ static void exponents_from_scale_factors(MPADecodeContext *s,
     bstab = band_size_long[s->sample_rate_index];
     pretab = mpa_pretab[g->preflag];
     for(i=0;i<g->long_end;i++) {
-        v0 = gain - ((g->scale_factors[i] + pretab[i]) << shift);
+        v0 = gain - ((g->scale_factors[i] + pretab[i]) << shift) + 400;
         len = bstab[i];
         for(j=len;j>0;j--)
             *exp_ptr++ = v0;
@@ -1649,7 +1631,7 @@ static void exponents_from_scale_factors(MPADecodeContext *s,
         for(i=g->short_start;i<13;i++) {
             len = bstab[i];
             for(l=0;l<3;l++) {
-                v0 = gains[l] - (g->scale_factors[k++] << shift);
+                v0 = gains[l] - (g->scale_factors[k++] << shift) + 400;
                 for(j=len;j>0;j--)
                 *exp_ptr++ = v0;
             }
@@ -1667,16 +1649,18 @@ static inline int get_bitsz(GetBitContext *s, int n)
 }
 
 static int huffman_decode(MPADecodeContext *s, GranuleDef *g,
-                          int16_t *exponents, int end_pos)
+                          int16_t *exponents, int end_pos2)
 {
     int s_index;
-    int linbits, code, x, y, l, v, i, j, k, pos;
-    int last_pos;
+    int i;
+    int last_pos, bits_left;
     VLC *vlc;
+    int end_pos= FFMIN(end_pos2, s->gb.size_in_bits);
 
     /* low frequencies (called big values) */
     s_index = 0;
     for(i=0;i<3;i++) {
+        int j, k, l, linbits;
         j = g->region_size[i];
         if (j == 0)
             continue;
@@ -1687,16 +1671,31 @@ static int huffman_decode(MPADecodeContext *s, GranuleDef *g,
         vlc = &huff_vlc[l];
 
         if(!l){
-            memset(&g->sb_hybrid[s_index], 0, sizeof(*g->sb_hybrid)*j);
+            memset(&g->sb_hybrid[s_index], 0, sizeof(*g->sb_hybrid)*2*j);
             s_index += 2*j;
             continue;
         }
 
         /* read huffcode and compute each couple */
         for(;j>0;j--) {
-            if (get_bits_count(&s->gb) >= end_pos)
-                break;
-            y = get_vlc2(&s->gb, vlc->table, 8, 3);
+            int exponent, x, y, v;
+            int pos= get_bits_count(&s->gb);
+
+            if (pos >= end_pos){
+//                av_log(NULL, AV_LOG_ERROR, "pos: %d %d %d %d\n", pos, end_pos, end_pos2, s_index);
+                if(s->in_gb.buffer && pos >= s->gb.size_in_bits){
+                    s->gb= s->in_gb;
+                    s->in_gb.buffer=NULL;
+                    assert((get_bits_count(&s->gb) & 7) == 0);
+                    skip_bits_long(&s->gb, pos - end_pos);
+                    end_pos= end_pos2 + get_bits_count(&s->gb) - pos;
+                    pos= get_bits_count(&s->gb);
+                }
+//                av_log(NULL, AV_LOG_ERROR, "new pos: %d %d\n", pos, end_pos);
+                if(pos >= end_pos)
+                    break;
+            }
+            y = get_vlc2(&s->gb, vlc->table, 7, 3);
 
             if(!y){
                 g->sb_hybrid[s_index  ] =
@@ -1705,31 +1704,48 @@ static int huffman_decode(MPADecodeContext *s, GranuleDef *g,
                 continue;
             }
 
-            x = y >> 4;
-            y = y & 0x0f;
+            exponent= exponents[s_index];
 
             dprintf("region=%d n=%d x=%d y=%d exp=%d\n",
-                    i, g->region_size[i] - j, x, y, exponents[s_index]);
-            if (x) {
-                if (x == 15)
+                    i, g->region_size[i] - j, x, y, exponent);
+            if(y&16){
+                x = y >> 5;
+                y = y & 0x0f;
+                if (x < 15){
+                    v = expval_table[ exponent ][ x ];
+//                      v = expval_table[ (exponent&3) ][ x ] >> FFMIN(0 - (exponent>>2), 31);
+                }else{
                     x += get_bitsz(&s->gb, linbits);
-                v = l3_unscale(x, exponents[s_index]);
+                    v = l3_unscale(x, exponent);
+                }
                 if (get_bits1(&s->gb))
                     v = -v;
-            } else {
-                v = 0;
-            }
-            g->sb_hybrid[s_index++] = v;
-            if (y) {
-                if (y == 15)
+                g->sb_hybrid[s_index] = v;
+                if (y < 15){
+                    v = expval_table[ exponent ][ y ];
+                }else{
                     y += get_bitsz(&s->gb, linbits);
-                v = l3_unscale(y, exponents[s_index]);
+                    v = l3_unscale(y, exponent);
+                }
                 if (get_bits1(&s->gb))
                     v = -v;
-            } else {
-                v = 0;
+                g->sb_hybrid[s_index+1] = v;
+            }else{
+                x = y >> 5;
+                y = y & 0x0f;
+                x += y;
+                if (x < 15){
+                    v = expval_table[ exponent ][ x ];
+                }else{
+                    x += get_bitsz(&s->gb, linbits);
+                    v = l3_unscale(x, exponent);
+                }
+                if (get_bits1(&s->gb))
+                    v = -v;
+                g->sb_hybrid[s_index+!!y] = v;
+                g->sb_hybrid[s_index+ !y] = 0;
             }
-            g->sb_hybrid[s_index++] = v;
+            s_index+=2;
         }
     }
 
@@ -1737,16 +1753,28 @@ static int huffman_decode(MPADecodeContext *s, GranuleDef *g,
     vlc = &huff_quad_vlc[g->count1table_select];
     last_pos=0;
     while (s_index <= 572) {
+        int pos, code;
         pos = get_bits_count(&s->gb);
         if (pos >= end_pos) {
-            if (pos > end_pos && last_pos){
+//                av_log(NULL, AV_LOG_ERROR, "pos2: %d %d %d %d\n", pos, end_pos, end_pos2, s_index);
+            if(s->in_gb.buffer && pos >= s->gb.size_in_bits){
+                s->gb= s->in_gb;
+                s->in_gb.buffer=NULL;
+                assert((get_bits_count(&s->gb) & 7) == 0);
+                skip_bits_long(&s->gb, pos - end_pos);
+                end_pos= end_pos2 + get_bits_count(&s->gb) - pos;
+                pos= get_bits_count(&s->gb);
+            }
+//                av_log(NULL, AV_LOG_ERROR, "new pos2: %d %d %d\n", pos, end_pos, s_index);
+            if (pos > end_pos && last_pos){ //FIXME last_pos is messed if we switch buffers
                 /* some encoders generate an incorrect size for this
                    part. We must go back into the data */
                 s_index -= 4;
-                init_get_bits(&s->gb, s->gb.buffer + 4*(last_pos>>5), s->gb.size_in_bits - (last_pos&(~31)));
-                skip_bits(&s->gb, last_pos&31);
+                skip_bits_long(&s->gb, last_pos - pos);
+                av_log(NULL, AV_LOG_DEBUG, "overread, skip %d\n", last_pos - pos);
             }
-            break;
+            if(pos >= end_pos)
+                break;
         }
         last_pos= pos;
 
@@ -1758,9 +1786,11 @@ static int huffman_decode(MPADecodeContext *s, GranuleDef *g,
         g->sb_hybrid[s_index+3]= 0;
         while(code){
             const static int idxtab[16]={3,3,2,2,1,1,1,1,0,0,0,0,0,0,0,0};
+            int v;
             int pos= s_index+idxtab[code];
             code ^= 8>>idxtab[code];
-            v = l3_unscale(1, exponents[pos]);
+            v = exp_table[ exponents[pos] ];
+//            v = exp_table[ (exponents[pos]&3) ] >> FFMIN(0 - (exponents[pos]>>2), 31);
             if(get_bits1(&s->gb))
                 v = -v;
             g->sb_hybrid[pos] = v;
@@ -1768,6 +1798,16 @@ static int huffman_decode(MPADecodeContext *s, GranuleDef *g,
         s_index+=4;
     }
     memset(&g->sb_hybrid[s_index], 0, sizeof(*g->sb_hybrid)*(576 - s_index));
+
+    /* skip extension bits */
+    bits_left = end_pos - get_bits_count(&s->gb);
+//av_log(NULL, AV_LOG_ERROR, "left:%d buf:%p\n", bits_left, s->in_gb.buffer);
+    if (bits_left < 0) {
+        dprintf("bits_left=%d\n", bits_left);
+        return -1;
+    }
+    skip_bits_long(&s->gb, bits_left);
+
     return 0;
 }
 
@@ -2153,7 +2193,7 @@ void sample_dump(int fnum, int32_t *tab, int n)
 static int mp_decode_layer3(MPADecodeContext *s)
 {
     int nb_granules, main_data_begin, private_bits;
-    int gr, ch, blocksplit_flag, i, j, k, n, bits_pos, bits_left;
+    int gr, ch, blocksplit_flag, i, j, k, n, bits_pos;
     GranuleDef granules[2][2], *g;
     int16_t exponents[576];
 
@@ -2277,9 +2317,16 @@ static int mp_decode_layer3(MPADecodeContext *s)
     }
 
   if (!s->adu_mode) {
+    const uint8_t *ptr = s->gb.buffer + (get_bits_count(&s->gb)>>3);
     /* now we get bits from the main_data_begin offset */
     dprintf("seekback: %d\n", main_data_begin);
-    seek_to_maindata(s, main_data_begin);
+//av_log(NULL, AV_LOG_ERROR, "backstep:%d, lastbuf:%d\n", main_data_begin, s->last_buf_size);
+    if(main_data_begin > s->last_buf_size)
+        s->last_buf_size= main_data_begin;
+
+    memcpy(s->last_buf + s->last_buf_size, ptr, EXTRABYTES);
+    s->in_gb= s->gb;
+    init_get_bits(&s->gb, s->last_buf + s->last_buf_size - main_data_begin, main_data_begin*8);
   }
 
     for(gr=0;gr<nb_granules;gr++) {
@@ -2421,19 +2468,6 @@ static int mp_decode_layer3(MPADecodeContext *s)
 #if defined(DEBUG)
             sample_dump(0, g->sb_hybrid, 576);
 #endif
-
-            /* skip extension bits */
-            bits_left = g->part2_3_length - (get_bits_count(&s->gb) - bits_pos);
-            if (bits_left < 0) {
-                dprintf("bits_left=%d\n", bits_left);
-                return -1;
-            }
-            while (bits_left >= 16) {
-                skip_bits(&s->gb, 16);
-                bits_left -= 16;
-            }
-            if (bits_left > 0)
-                skip_bits(&s->gb, bits_left);
         } /* ch */
 
         if (s->nb_channels == 2)
@@ -2460,13 +2494,12 @@ static int mp_decode_layer3(MPADecodeContext *s)
 }
 
 static int mp_decode_frame(MPADecodeContext *s,
-                           OUT_INT *samples)
+                           OUT_INT *samples, const uint8_t *buf, int buf_size)
 {
     int i, nb_frames, ch;
     OUT_INT *samples_ptr;
 
-    init_get_bits(&s->gb, s->inbuf + HEADER_SIZE,
-                  (s->inbuf_ptr - s->inbuf - HEADER_SIZE)*8);
+    init_get_bits(&s->gb, buf + HEADER_SIZE, (buf_size - HEADER_SIZE)*8);
 
     /* skip error protection field */
     if (s->error_protection)
@@ -2483,6 +2516,28 @@ static int mp_decode_frame(MPADecodeContext *s,
     case 3:
     default:
         nb_frames = mp_decode_layer3(s);
+
+        s->last_buf_size=0;
+        if(s->in_gb.buffer){
+            align_get_bits(&s->gb);
+            i= (s->gb.size_in_bits - get_bits_count(&s->gb))>>3;
+            if(i > 0 && i <= BACKSTEP_SIZE){
+                memmove(s->last_buf, s->gb.buffer + (get_bits_count(&s->gb)>>3), i);
+                s->last_buf_size=i;
+            }
+            s->gb= s->in_gb;
+        }
+
+        align_get_bits(&s->gb);
+        assert((get_bits_count(&s->gb) & 7) == 0);
+        i= (s->gb.size_in_bits - get_bits_count(&s->gb))>>3;
+
+        if(i<0 || s->last_buf_size + i > BACKSTEP_SIZE || nb_frames<0)
+            i= FFMIN(BACKSTEP_SIZE-s->last_buf_size, buf_size - HEADER_SIZE);
+        assert(i <= buf_size - HEADER_SIZE && i>= 0);
+            memcpy(s->last_buf + s->last_buf_size, s->gb.buffer + buf_size - HEADER_SIZE - i, i);
+        s->last_buf_size += i;
+
         break;
     }
 #if defined(DEBUG)
@@ -2519,159 +2574,58 @@ static int decode_frame(AVCodecContext * avctx,
 {
     MPADecodeContext *s = avctx->priv_data;
     uint32_t header;
-    uint8_t *buf_ptr;
-    int len, out_size;
+    int out_size;
     OUT_INT *out_samples = data;
 
-    buf_ptr = buf;
-    while (buf_size > 0) {
-        len = s->inbuf_ptr - s->inbuf;
-        if (s->frame_size == 0) {
-            /* special case for next header for first frame in free
-               format case (XXX: find a simpler method) */
-            if (s->free_format_next_header != 0) {
-                s->inbuf[0] = s->free_format_next_header >> 24;
-                s->inbuf[1] = s->free_format_next_header >> 16;
-                s->inbuf[2] = s->free_format_next_header >> 8;
-                s->inbuf[3] = s->free_format_next_header;
-                s->inbuf_ptr = s->inbuf + 4;
-                s->free_format_next_header = 0;
-                goto got_header;
-            }
-            /* no header seen : find one. We need at least HEADER_SIZE
-               bytes to parse it */
-            len = HEADER_SIZE - len;
-            if (len > buf_size)
-                len = buf_size;
-            if (len > 0) {
-                memcpy(s->inbuf_ptr, buf_ptr, len);
-                buf_ptr += len;
-                buf_size -= len;
-                s->inbuf_ptr += len;
-            }
-            if ((s->inbuf_ptr - s->inbuf) >= HEADER_SIZE) {
-            got_header:
-                header = (s->inbuf[0] << 24) | (s->inbuf[1] << 16) |
-                    (s->inbuf[2] << 8) | s->inbuf[3];
-
-                if (ff_mpa_check_header(header) < 0) {
-                    /* no sync found : move by one byte (inefficient, but simple!) */
-                    memmove(s->inbuf, s->inbuf + 1, s->inbuf_ptr - s->inbuf - 1);
-                    s->inbuf_ptr--;
-                    dprintf("skip %x\n", header);
-                    /* reset free format frame size to give a chance
-                       to get a new bitrate */
-                    s->free_format_frame_size = 0;
-                } else {
-                    if (decode_header(s, header) == 1) {
-                        /* free format: prepare to compute frame size */
-                        s->frame_size = -1;
-                    }
-                    /* update codec info */
-                    avctx->sample_rate = s->sample_rate;
-                    avctx->channels = s->nb_channels;
-                    avctx->bit_rate = s->bit_rate;
-                    avctx->sub_id = s->layer;
-                    switch(s->layer) {
-                    case 1:
-                        avctx->frame_size = 384;
-                        break;
-                    case 2:
-                        avctx->frame_size = 1152;
-                        break;
-                    case 3:
-                        if (s->lsf)
-                            avctx->frame_size = 576;
-                        else
-                            avctx->frame_size = 1152;
-                        break;
-                    }
-                }
-            }
-        } else if (s->frame_size == -1) {
-            /* free format : find next sync to compute frame size */
-            len = MPA_MAX_CODED_FRAME_SIZE - len;
-            if (len > buf_size)
-                len = buf_size;
-            if (len == 0) {
-                /* frame too long: resync */
-                s->frame_size = 0;
-                memmove(s->inbuf, s->inbuf + 1, s->inbuf_ptr - s->inbuf - 1);
-                s->inbuf_ptr--;
-            } else {
-                uint8_t *p, *pend;
-                uint32_t header1;
-                int padding;
-
-                memcpy(s->inbuf_ptr, buf_ptr, len);
-                /* check for header */
-                p = s->inbuf_ptr - 3;
-                pend = s->inbuf_ptr + len - 4;
-                while (p <= pend) {
-                    header = (p[0] << 24) | (p[1] << 16) |
-                        (p[2] << 8) | p[3];
-                    header1 = (s->inbuf[0] << 24) | (s->inbuf[1] << 16) |
-                        (s->inbuf[2] << 8) | s->inbuf[3];
-                    /* check with high probability that we have a
-                       valid header */
-                    if ((header & SAME_HEADER_MASK) ==
-                        (header1 & SAME_HEADER_MASK)) {
-                        /* header found: update pointers */
-                        len = (p + 4) - s->inbuf_ptr;
-                        buf_ptr += len;
-                        buf_size -= len;
-                        s->inbuf_ptr = p;
-                        /* compute frame size */
-                        s->free_format_next_header = header;
-                        s->free_format_frame_size = s->inbuf_ptr - s->inbuf;
-                        padding = (header1 >> 9) & 1;
-                        if (s->layer == 1)
-                            s->free_format_frame_size -= padding * 4;
-                        else
-                            s->free_format_frame_size -= padding;
-                        dprintf("free frame size=%d padding=%d\n",
-                                s->free_format_frame_size, padding);
-                        decode_header(s, header1);
-                        goto next_data;
-                    }
-                    p++;
-                }
-                /* not found: simply increase pointers */
-                buf_ptr += len;
-                s->inbuf_ptr += len;
-                buf_size -= len;
-            }
-        } else if (len < s->frame_size) {
-            if (s->frame_size > MPA_MAX_CODED_FRAME_SIZE)
-                s->frame_size = MPA_MAX_CODED_FRAME_SIZE;
-            len = s->frame_size - len;
-            if (len > buf_size)
-                len = buf_size;
-            memcpy(s->inbuf_ptr, buf_ptr, len);
-            buf_ptr += len;
-            s->inbuf_ptr += len;
-            buf_size -= len;
-        }
-    next_data:
-        if (s->frame_size > 0 &&
-            (s->inbuf_ptr - s->inbuf) >= s->frame_size) {
-            if (avctx->parse_only) {
-                /* simply return the frame data */
-                *(uint8_t **)data = s->inbuf;
-                out_size = s->inbuf_ptr - s->inbuf;
-            } else {
-                out_size = mp_decode_frame(s, out_samples);
-            }
-            s->inbuf_ptr = s->inbuf;
-            s->frame_size = 0;
-            if(out_size>=0)
-                *data_size = out_size;
-            else
-                av_log(avctx, AV_LOG_DEBUG, "Error while decoding mpeg audio frame\n"); //FIXME return -1 / but also return the number of bytes consumed
-            break;
-        }
+retry:
+    if(buf_size < HEADER_SIZE)
+        return -1;
+
+    header = (buf[0] << 24) | (buf[1] << 16) | (buf[2] << 8) | buf[3];
+    if(ff_mpa_check_header(header) < 0){
+        buf++;
+//        buf_size--;
+        av_log(avctx, AV_LOG_ERROR, "header missing skiping one byte\n");
+        goto retry;
+    }
+
+    if (decode_header(s, header) == 1) {
+        /* free format: prepare to compute frame size */
+        s->frame_size = -1;
+        return -1;
+    }
+    /* update codec info */
+    avctx->sample_rate = s->sample_rate;
+    avctx->channels = s->nb_channels;
+    avctx->bit_rate = s->bit_rate;
+    avctx->sub_id = s->layer;
+    switch(s->layer) {
+    case 1:
+        avctx->frame_size = 384;
+        break;
+    case 2:
+        avctx->frame_size = 1152;
+        break;
+    case 3:
+        if (s->lsf)
+            avctx->frame_size = 576;
+        else
+            avctx->frame_size = 1152;
+        break;
     }
-    return buf_ptr - buf;
+
+    if(s->frame_size<=0 || s->frame_size < buf_size){
+        av_log(avctx, AV_LOG_ERROR, "incomplete frame\n");
+        return -1;
+    }
+
+    out_size = mp_decode_frame(s, out_samples, buf, buf_size);
+    if(out_size>=0)
+        *data_size = out_size;
+    else
+        av_log(avctx, AV_LOG_DEBUG, "Error while decoding mpeg audio frame\n"); //FIXME return -1 / but also return the number of bytes consumed
+    s->frame_size = 0;
+    return buf_size;
 }
 
 
@@ -2696,12 +2650,8 @@ static int decode_frame_adu(AVCodecContext * avctx,
     if (len > MPA_MAX_CODED_FRAME_SIZE)
         len = MPA_MAX_CODED_FRAME_SIZE;
 
-    memcpy(s->inbuf, buf, len);
-    s->inbuf_ptr = s->inbuf + len;
-
     // Get header and restore sync word
-    header = (s->inbuf[0] << 24) | (s->inbuf[1] << 16) |
-              (s->inbuf[2] << 8) | s->inbuf[3] | 0xffe00000;
+    header = (buf[0] << 24) | (buf[1] << 16) | (buf[2] << 8) | buf[3] | 0xffe00000;
 
     if (ff_mpa_check_header(header) < 0) { // Bad header, discard frame
         *data_size = 0;
@@ -2718,11 +2668,9 @@ static int decode_frame_adu(AVCodecContext * avctx,
     avctx->frame_size=s->frame_size = len;
 
     if (avctx->parse_only) {
-        /* simply return the frame data */
-        *(uint8_t **)data = s->inbuf;
-        out_size = s->inbuf_ptr - s->inbuf;
+        out_size = buf_size;
     } else {
-        out_size = mp_decode_frame(s, out_samples);
+        out_size = mp_decode_frame(s, out_samples, buf, buf_size);
     }
 
     *data_size = out_size;
@@ -2785,8 +2733,6 @@ static int decode_init_mp3on4(AVCodecContext * avctx)
     for (i = 1; i < s->frames; i++) {
         s->mp3decctx[i] = av_mallocz(sizeof(MPADecodeContext));
         s->mp3decctx[i]->compute_antialias = s->mp3decctx[0]->compute_antialias;
-        s->mp3decctx[i]->inbuf = &s->mp3decctx[i]->inbuf1[0][BACKSTEP_SIZE];
-        s->mp3decctx[i]->inbuf_ptr = s->mp3decctx[i]->inbuf;
         s->mp3decctx[i]->adu_mode = 1;
     }
 
@@ -2846,13 +2792,9 @@ static int decode_frame_mp3on4(AVCodecContext * avctx,
             fsize = MPA_MAX_CODED_FRAME_SIZE;
         m = s->mp3decctx[fr];
         assert (m != NULL);
-        /* copy original to new */
-        m->inbuf_ptr = m->inbuf + fsize;
-        memcpy(m->inbuf, start, fsize);
 
         // Get header
-        header = (m->inbuf[0] << 24) | (m->inbuf[1] << 16) |
-                  (m->inbuf[2] << 8) | m->inbuf[3] | 0xfff00000;
+        header = (start[0] << 24) | (start[1] << 16) | (start[2] << 8) | start[3] | 0xfff00000;
 
         if (ff_mpa_check_header(header) < 0) { // Bad header, discard block
             *data_size = 0;
@@ -2860,7 +2802,7 @@ static int decode_frame_mp3on4(AVCodecContext * avctx,
         }
 
         decode_header(m, header);
-        mp_decode_frame(m, decoded_buf);
+        mp_decode_frame(m, decoded_buf, start, fsize);
 
         n = MPA_FRAME_SIZE * m->nb_channels;
         out_size += n * sizeof(OUT_INT);