hevc: move restore_tqb where it should be.
[ffmpeg.git] / libavcodec / flac.c
index 77854d5..aeb276b 100644 (file)
 /*
- * FLAC (Free Lossless Audio Codec) decoder
- * Copyright (c) 2003 Alex Beregszaszi
+ * FLAC common code
+ * Copyright (c) 2009 Justin Ruggles
  *
- * This library is free software; you can redistribute it and/or
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
- * version 2 of the License, or (at your option) any later version.
+ * version 2.1 of the License, or (at your option) any later version.
  *
- * This library is distributed in the hope that it will be useful,
+ * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
- */
-
-/**
- * @file flac.c
- * FLAC (Free Lossless Audio Codec) decoder
- * @author Alex Beregszaszi
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
-#include "avcodec.h"
-#include "golomb.h"
-
-#define MAX_CHANNELS 8
-#define MAX_BLOCKSIZE 65535
 
-enum channel_order {
-    INDEPENDENT,
-    LEFT_SIDE,
-    RIGHT_SIDE,
-    MID_SIDE,
+#include "libavutil/channel_layout.h"
+#include "libavutil/crc.h"
+#include "libavutil/log.h"
+#include "bytestream.h"
+#include "get_bits.h"
+#include "flac.h"
+#include "flacdata.h"
+
+static const int8_t sample_size_table[] = { 0, 8, 12, 0, 16, 20, 24, 0 };
+
+static const uint64_t flac_channel_layouts[8] = {
+    AV_CH_LAYOUT_MONO,
+    AV_CH_LAYOUT_STEREO,
+    AV_CH_LAYOUT_SURROUND,
+    AV_CH_LAYOUT_QUAD,
+    AV_CH_LAYOUT_5POINT0,
+    AV_CH_LAYOUT_5POINT1,
+    AV_CH_LAYOUT_6POINT1,
+    AV_CH_LAYOUT_7POINT1
 };
 
-typedef struct FLACContext {
-    AVCodecContext *avctx;
-    GetBitContext gb;
-
-    int min_blocksize, max_blocksize;
-    int min_framesize, max_framesize;
-    int samplerate, channels;
-    int blocksize, last_blocksize;
-    int bps, curr_bps;
-    enum channel_order order;
-
-    uint8_t *residual[MAX_CHANNELS];
-    uint32_t *decoded[MAX_CHANNELS];
-} FLACContext;
-
-#define METADATA_TYPE_STREAMINFO 0
-
-static int sample_rate_table[] =
-{ 0, 0, 0, 0,
-  8000, 16000, 22050, 24000, 32000, 44100, 48000, 96000,
-  0, 0, 0, 0 }; 
-
-static int sample_size_table[] = 
-{ 0, 8, 12, 0, 16, 20, 24, 0 };
-
-static uint64_t get_uvlc(GetBitContext *gb, int is64)
+static int64_t get_utf8(GetBitContext *gb)
 {
-    uint64_t val = 0;
-    int i = 0;
-
-    while(i++ < 5+is64)
-    {
-        const int tmp = get_bits(gb, 8);
-        
-        if (tmp & 0x80)
-            val = (val << 7) + tmp - 0x80;
-        else
-            return (val << 7) + tmp;
-    }
-    return -1;
+    int64_t val;
+    GET_UTF8(val, get_bits(gb, 8), return -1;)
+    return val;
 }
 
-static int flac_decode_init(AVCodecContext * avctx)
+int ff_flac_decode_frame_header(AVCodecContext *avctx, GetBitContext *gb,
+                                FLACFrameInfo *fi, int log_level_offset)
 {
-    return 0;
-}
+    int bs_code, sr_code, bps_code;
+
+    /* frame sync code */
+    if ((get_bits(gb, 15) & 0x7FFF) != 0x7FFC) {
+        av_log(avctx, AV_LOG_ERROR + log_level_offset, "invalid sync code\n");
+        return AVERROR_INVALIDDATA;
+    }
+
+    /* variable block size stream code */
+    fi->is_var_size = get_bits1(gb);
+
+    /* block size and sample rate codes */
+    bs_code = get_bits(gb, 4);
+    sr_code = get_bits(gb, 4);
+
+    /* channels and decorrelation */
+    fi->ch_mode = get_bits(gb, 4);
+    if (fi->ch_mode < FLAC_MAX_CHANNELS) {
+        fi->channels = fi->ch_mode + 1;
+        fi->ch_mode = FLAC_CHMODE_INDEPENDENT;
+    } else if (fi->ch_mode < FLAC_MAX_CHANNELS + FLAC_CHMODE_MID_SIDE) {
+        fi->channels = 2;
+        fi->ch_mode -= FLAC_MAX_CHANNELS - 1;
+    } else {
+        av_log(avctx, AV_LOG_ERROR + log_level_offset,
+               "invalid channel mode: %d\n", fi->ch_mode);
+        return AVERROR_INVALIDDATA;
+    }
+
+    /* bits per sample */
+    bps_code = get_bits(gb, 3);
+    if (bps_code == 3 || bps_code == 7) {
+        av_log(avctx, AV_LOG_ERROR + log_level_offset,
+               "invalid sample size code (%d)\n",
+               bps_code);
+        return AVERROR_INVALIDDATA;
+    }
+    fi->bps = sample_size_table[bps_code];
+
+    /* reserved bit */
+    if (get_bits1(gb)) {
+        av_log(avctx, AV_LOG_ERROR + log_level_offset,
+               "broken stream, invalid padding\n");
+        return AVERROR_INVALIDDATA;
+    }
+
+    /* sample or frame count */
+    fi->frame_or_sample_num = get_utf8(gb);
+    if (fi->frame_or_sample_num < 0) {
+        av_log(avctx, AV_LOG_ERROR + log_level_offset,
+               "sample/frame number invalid; utf8 fscked\n");
+        return AVERROR_INVALIDDATA;
+    }
+
+    /* blocksize */
+    if (bs_code == 0) {
+        av_log(avctx, AV_LOG_ERROR + log_level_offset,
+               "reserved blocksize code: 0\n");
+        return AVERROR_INVALIDDATA;
+    } else if (bs_code == 6) {
+        fi->blocksize = get_bits(gb, 8) + 1;
+    } else if (bs_code == 7) {
+        fi->blocksize = get_bits(gb, 16) + 1;
+    } else {
+        fi->blocksize = ff_flac_blocksize_table[bs_code];
+    }
+
+    /* sample rate */
+    if (sr_code < 12) {
+        fi->samplerate = ff_flac_sample_rate_table[sr_code];
+    } else if (sr_code == 12) {
+        fi->samplerate = get_bits(gb, 8) * 1000;
+    } else if (sr_code == 13) {
+        fi->samplerate = get_bits(gb, 16);
+    } else if (sr_code == 14) {
+        fi->samplerate = get_bits(gb, 16) * 10;
+    } else {
+        av_log(avctx, AV_LOG_ERROR + log_level_offset,
+               "illegal sample rate code %d\n",
+               sr_code);
+        return AVERROR_INVALIDDATA;
+    }
+
+    /* header CRC-8 check */
+    skip_bits(gb, 8);
+    if (av_crc(av_crc_get_table(AV_CRC_8_ATM), 0, gb->buffer,
+               get_bits_count(gb)/8)) {
+        av_log(avctx, AV_LOG_ERROR + log_level_offset,
+               "header crc mismatch\n");
+        return AVERROR_INVALIDDATA;
+    }
 
-static void dump_headers(FLACContext *s)
-{
-    printf("  Blocksize: %d .. %d (%d)\n", s->min_blocksize, s->max_blocksize, s->blocksize);
-    printf("  Framesize: %d .. %d\n", s->min_framesize, s->max_framesize);
-    printf("  Samplerate: %d\n", s->samplerate);
-    printf("  Channels: %d\n", s->channels);
-    printf("  Bits: %d\n", s->bps);
+    return 0;
 }
 
-static void metadata_streaminfo(FLACContext *s)
+int ff_flac_get_max_frame_size(int blocksize, int ch, int bps)
 {
-    int i;
-
-    /* mandatory streaminfo */
-    s->min_blocksize = get_bits(&s->gb, 16);
-    s->max_blocksize = get_bits(&s->gb, 16);
-
-    s->min_framesize = get_bits_long(&s->gb, 24);
-    s->max_framesize = get_bits_long(&s->gb, 24);
-    
-    s->samplerate = get_bits_long(&s->gb, 20);
-    s->channels = get_bits(&s->gb, 3) + 1;
-    s->bps = get_bits(&s->gb, 5) + 1;
-    
-    s->avctx->channels = s->channels;
-    s->avctx->sample_rate = s->samplerate;
+    /* Technically, there is no limit to FLAC frame size, but an encoder
+       should not write a frame that is larger than if verbatim encoding mode
+       were to be used. */
 
-    skip_bits(&s->gb, 36); /* total num of samples */
-    
-    skip_bits(&s->gb, 64); /* md5 sum */
-    skip_bits(&s->gb, 64); /* md5 sum */
+    int count;
 
-    for (i = 0; i < s->channels; i++)
-    {
-        s->decoded[i] = av_realloc(s->decoded[i], sizeof(uint32_t)*s->max_blocksize);
-        s->residual[i] = av_realloc(s->residual[i], sizeof(uint8_t)*s->max_blocksize);
+    count = 16;                  /* frame header */
+    count += ch * ((7+bps+7)/8); /* subframe headers */
+    if (ch == 2) {
+        /* for stereo, need to account for using decorrelation */
+        count += (( 2*bps+1) * blocksize + 7) / 8;
+    } else {
+        count += ( ch*bps    * blocksize + 7) / 8;
     }
+    count += 2; /* frame footer */
+
+    return count;
 }
 
-static int decode_residuals(FLACContext *s, int channel, int pred_order)
+int avpriv_flac_is_extradata_valid(AVCodecContext *avctx,
+                               enum FLACExtradataFormat *format,
+                               uint8_t **streaminfo_start)
 {
-    int i, tmp, partition, method_type, rice_order;
-    int sample = 0, samples;
-
-    method_type = get_bits(&s->gb, 2);
-    if (method_type != 0)
-        return -1;
-    
-    rice_order = get_bits(&s->gb, 4);
-
-    samples = (rice_order > 0) ?
-        (s->blocksize >> rice_order) : (s->blocksize - pred_order);
-
-    for (partition = 0; partition < (1 << rice_order); partition++)
-    {
-        tmp = get_bits(&s->gb, 4);
-        if (tmp == 0)
-        {
-            i = (!rice_order || partition) ? 0 : pred_order;
-            for (; i < samples; i++, sample++)
-                s->residual[channel][sample] = get_sr_golomb_flac(&s->gb, tmp, 0, 0);
-            printf("zero k\n");
-        }
-        else if (tmp == 15)
-        {
-            printf("fixed len partition\n");
-            tmp = get_bits(&s->gb, 5);
-            i = (!rice_order || partition) ? 0 : pred_order;
-            for (; i < samples; i++, sample++)
-                s->residual[channel][sample] = get_bits(&s->gb, tmp);
+    if (!avctx->extradata || avctx->extradata_size < FLAC_STREAMINFO_SIZE) {
+        av_log(avctx, AV_LOG_ERROR, "extradata NULL or too small.\n");
+        return 0;
+    }
+    if (AV_RL32(avctx->extradata) != MKTAG('f','L','a','C')) {
+        /* extradata contains STREAMINFO only */
+        if (avctx->extradata_size != FLAC_STREAMINFO_SIZE) {
+            av_log(avctx, AV_LOG_WARNING, "extradata contains %d bytes too many.\n",
+                   FLAC_STREAMINFO_SIZE-avctx->extradata_size);
         }
-        else
-        {
-//            printf("rice coded partition\n");
-#if 1
-            i = (!rice_order || partition) ? 0 : pred_order;
-            for (; i < samples; i++, sample++)
-                s->residual[channel][sample] = get_sr_golomb_flac(&s->gb, tmp, 0, 0);
-#else
-            i = ((!rice_order || partition) ? samples : samples - pred_order) + sample;
-            for (; sample < i; sample++)
-                s->residual[channel][sample] = get_ur_golomb(&s->gb, tmp, 0, 0);
-//                s->residual[channel][sample] = get_se_golomb(&s->gb);
-#endif
+        *format = FLAC_EXTRADATA_FORMAT_STREAMINFO;
+        *streaminfo_start = avctx->extradata;
+    } else {
+        if (avctx->extradata_size < 8+FLAC_STREAMINFO_SIZE) {
+            av_log(avctx, AV_LOG_ERROR, "extradata too small.\n");
+            return 0;
         }
+        *format = FLAC_EXTRADATA_FORMAT_FULL_HEADER;
+        *streaminfo_start = &avctx->extradata[8];
     }
-
-    printf("partitions: %d, samples: %d\n", 1 << rice_order, sample);
-
-    return 0;
-}    
-
-static int decode_subframe_fixed(FLACContext *s, int channel, int pred_order)
-{
-    int i;
-        
-    printf("  SUBFRAME FIXED\n");
-        
-    /* warm up samples */
-    printf("   warm up samples: %d\n", pred_order);
-        
-    for (i = 0; i < pred_order; i++)
-    {
-        s->decoded[channel][i] = get_bits(&s->gb, s->curr_bps);
-        printf("    %d: %d\n", i, s->decoded[channel][i]);
-    }
-    
-    if (decode_residuals(s, channel, pred_order) < 0)
-        return -1;
-
-    switch(pred_order)
-    {
-        case 0:
-            for (i = pred_order; i < s->blocksize; i++)
-                s->decoded[channel][i] = s->residual[channel][i];
-            break;
-        case 1:
-            for (i = pred_order; i < s->blocksize; i++)
-                s->decoded[channel][i] = s->residual[channel][i] +
-                                        s->decoded[channel][i-1];
-            break;
-        case 2:
-            for (i = pred_order; i < s->blocksize; i++)
-                s->decoded[channel][i] = s->residual[channel][i] +
-                                        (s->decoded[channel][i-1] << 1) -
-                                        s->decoded[channel][i-2];
-            break;
-        case 3:
-            for (i = pred_order; i < s->blocksize; i++)
-                s->decoded[channel][i] = s->residual[channel][i] +
-                                        (((s->decoded[channel][i-1] -
-                                        s->decoded[channel][i-2]) << 1) +
-                                        (s->decoded[channel][i-1] -
-                                        s->decoded[channel][i-2])) +
-                                        s->decoded[channel][i-3];
-            break;
-        case 4:
-            for (i = pred_order; i < s->blocksize; i++)
-                s->decoded[channel][i] = s->residual[channel][i] +
-                                        ((s->decoded[channel][i-1] +
-                                        s->decoded[channel][i-3]) << 2) -
-                                        ((s->decoded[channel][i-2] << 2) +
-                                        (s->decoded[channel][i-2] << 1)) -
-                                        s->decoded[channel][i-4];
-            break;
-    }
-    
-    return 0;
-}
-
-static int decode_subframe_lpc(FLACContext *s, int channel, int pred_order)
-{
-    int sum, i, j;
-    int coeff_prec, qlevel;
-    int coeffs[pred_order];
-        
-    printf("  SUBFRAME LPC\n");
-        
-    /* warm up samples */
-    printf("   warm up samples: %d\n", pred_order);
-        
-    for (i = 0; i < pred_order; i++)
-    {
-        s->decoded[channel][i] = get_bits(&s->gb, s->curr_bps);
-        printf("    %d: %d\n", i, s->decoded[channel][i]);
-    }
-    
-    coeff_prec = get_bits(&s->gb, 4) + 1;
-    if (coeff_prec == 16)
-    {
-        printf("invalid coeff precision\n");
-        return -1;
-    }
-    printf("   qlp coeff prec: %d\n", coeff_prec);
-    qlevel = get_bits(&s->gb, 5);
-    printf("   quant level: %d\n", qlevel);
-    
-    for (i = 0; i < pred_order; i++)
-    {
-        coeffs[i] = get_bits(&s->gb, coeff_prec);
-        printf("    %d: %d\n", i, coeffs[i]);
-    }
-    
-    if (decode_residuals(s, channel, pred_order) < 0)
-        return -1;
-
-    for (i = pred_order; i < s->blocksize; i++)
-    {
-        sum = 0;
-        for (j = 0; j < pred_order; j++)
-            sum += coeffs[j] * s->decoded[channel][i-j-1];
-        s->decoded[channel][i] = s->residual[channel][i] + (sum >> qlevel);
-    }
-    
-    return 0;
+    return 1;
 }
 
-static inline int decode_subframe(FLACContext *s, int channel)
+void ff_flac_set_channel_layout(AVCodecContext *avctx)
 {
-    int type, wasted = 0;
-    int i, tmp;
-    
-    s->curr_bps = s->bps;
-    
-    if (get_bits1(&s->gb))
-    {
-        printf("invalid subframe padding\n");
-        return -1;
-    }
-    type = get_bits(&s->gb, 6);
-//    wasted = get_bits1(&s->gb);
-    
-//    if (wasted)
-//    {
-//        while (!get_bits1(&s->gb))
-//            wasted++;
-//        if (wasted)
-//            wasted++;
-//        s->curr_bps -= wasted;
-//    }
-
-    if (get_bits1(&s->gb))
-    {
-        wasted = 1;
-        while (!get_bits1(&s->gb))
-            wasted++;
-        s->curr_bps -= wasted;
-    }
-
-    if (type == 0)
-    {
-        printf("coding type: constant\n");
-        tmp = get_bits(&s->gb, s->curr_bps);
-        for (i = 0; i < s->blocksize; i++)
-            s->decoded[channel][i] = tmp;
-    }
-    else if (type == 1)
-    {
-        printf("coding type: verbatim\n");
-        for (i = 0; i < s->blocksize; i++)
-            s->decoded[channel][i] = get_bits(&s->gb, s->curr_bps);
-    }
-    else if ((type >= 8) && (type <= 12))
-    {
-        printf("coding type: fixed\n");
-        if (decode_subframe_fixed(s, channel, type & ~0x8) < 0)
-            return -1;
-    }
-    else if (type >= 32)
-    {
-        printf("coding type: lpc\n");
-        if (decode_subframe_lpc(s, channel, (type & ~0x20)+1) < 0)
-            return -1;
-    }
+    if (avctx->channels <= FF_ARRAY_ELEMS(flac_channel_layouts))
+        avctx->channel_layout = flac_channel_layouts[avctx->channels - 1];
     else
-    {
-        printf("invalid coding type\n");
-        return -1;
-    }
-        
-    if (wasted)
-    {
-        int i;
-        for (i = 0; i < s->blocksize; i++)
-            s->decoded[channel][i] <<= wasted;
-    }
-
-    return 0;
+        avctx->channel_layout = 0;
 }
 
-static int decode_frame(FLACContext *s)
+void avpriv_flac_parse_streaminfo(AVCodecContext *avctx, struct FLACStreaminfo *s,
+                              const uint8_t *buffer)
 {
-    int blocksize_code, sample_rate_code, sample_size_code, assignment, i;
-    
-    blocksize_code = get_bits(&s->gb, 4);
-    if (blocksize_code == 0)
-        s->blocksize = s->min_blocksize;
-    else if (blocksize_code == 1)
-        s->blocksize = 192;
-    else if (blocksize_code <= 5)
-        s->blocksize = 576 << (blocksize_code - 2);
-    else if (blocksize_code >= 8)
-        s->blocksize = 256 << (blocksize_code - 8);
-
-    sample_rate_code = get_bits(&s->gb, 4);
-    if ((sample_rate_code > 3) && (sample_rate_code < 12))
-        s->samplerate = sample_rate_table[sample_rate_code];
-    
-    assignment = get_bits(&s->gb, 4); /* channel assignment */
-    if (assignment < 8)
-    {
-        s->order = INDEPENDENT;
-        if (s->channels != assignment+1)
-            printf("channel number and number of assigned channels differ!\n");
-        printf("channels: %d\n", assignment+1);
-    }
-    else if (assignment == 8)
-    {
-        s->order = LEFT_SIDE;
-        printf("left/side\n");
-    }
-    else if (assignment == 9)
-    {
-        s->order = RIGHT_SIDE;
-        printf("right/side\n");
-    }
-    else if (assignment == 10)
-    {
-        s->order = MID_SIDE;
-        printf("mid/side\n");
-    }
-    else
-    {
-        printf("unsupported channel assignment\n");
-        return -1;
-    }
-
-    if ((assignment >= 8) && (s->channels != 2))
-    {
-        return -1;
-    }
-        
-    sample_size_code = get_bits(&s->gb, 3);
-    if (s->bps != 0)
-        s->bps = sample_size_table[sample_size_code];
+    GetBitContext gb;
+    init_get_bits(&gb, buffer, FLAC_STREAMINFO_SIZE*8);
 
-    if ((sample_size_code == 3) || (sample_size_code == 7))
-    {
-        printf("invalid sample size code (%d)\n", sample_size_code);
-        return -1;
+    skip_bits(&gb, 16); /* skip min blocksize */
+    s->max_blocksize = get_bits(&gb, 16);
+    if (s->max_blocksize < FLAC_MIN_BLOCKSIZE) {
+        av_log(avctx, AV_LOG_WARNING, "invalid max blocksize: %d\n",
+               s->max_blocksize);
+        s->max_blocksize = 16;
     }
 
-    if (get_bits1(&s->gb))
-    {
-        printf("broken stream, invalid padding\n");
-//        return -1;
-    }
-    
-    if (((blocksize_code == 6) || (blocksize_code == 7)) &&
-        (s->min_blocksize != s->max_blocksize))
-    {
-        get_uvlc(&s->gb, 1);
-    }
-    else
-        get_uvlc(&s->gb, 0);
-    
-    if (blocksize_code == 6)
-        s->blocksize = get_bits(&s->gb, 8)+1;
-    if (blocksize_code == 7)
-        s->blocksize = get_bits(&s->gb, 16)+1;
+    skip_bits(&gb, 24); /* skip min frame size */
+    s->max_framesize = get_bits_long(&gb, 24);
 
-    if ((sample_rate_code > 11) && (sample_rate_code < 15))
-    {
-        switch(sample_rate_code)
-        {
-            case 12:
-                s->samplerate = get_bits(&s->gb, 8) * 1000;
-                break;
-            case 13:
-                s->samplerate = get_bits(&s->gb, 16);
-                break;
-            case 14:
-                s->samplerate = get_bits(&s->gb, 16) * 10;
-                break;
-        }
-    }
+    s->samplerate = get_bits_long(&gb, 20);
+    s->channels = get_bits(&gb, 3) + 1;
+    s->bps = get_bits(&gb, 5) + 1;
 
-    skip_bits(&s->gb, 8); /* header crc */
+    avctx->channels = s->channels;
+    avctx->sample_rate = s->samplerate;
+    avctx->bits_per_raw_sample = s->bps;
 
-    dump_headers(s);
+    if (!avctx->channel_layout ||
+        av_get_channel_layout_nb_channels(avctx->channel_layout) != avctx->channels)
+        ff_flac_set_channel_layout(avctx);
 
-    /* subframes */
-    for (i = 0; i < s->channels; i++)
-    {
-        if (s->blocksize != s->last_blocksize)
-        {
-            s->decoded[i] = av_realloc(s->decoded[i], sizeof(uint32_t)*s->blocksize);
-            s->residual[i] = av_realloc(s->residual[i], sizeof(uint8_t)*s->blocksize);
-        }
-        printf("decoded: %x residual: %x\n", s->decoded[i], s->residual[i]);
-        if (decode_subframe(s, i) < 0)
-            return -1;
-    }
-    
-    align_get_bits(&s->gb);
-
-    /* frame footer */
-    skip_bits(&s->gb, 16); /* data crc */
+    s->samples = get_bits64(&gb, 36);
 
-    return 0;
+    skip_bits_long(&gb, 64); /* md5 sum */
+    skip_bits_long(&gb, 64); /* md5 sum */
 }
 
-static int flac_decode_frame(AVCodecContext *avctx,
-                            void *data, int *data_size,
-                            uint8_t *buf, int buf_size)
+#if LIBAVCODEC_VERSION_MAJOR < 56
+void avpriv_flac_parse_block_header(const uint8_t *block_header,
+                                int *last, int *type, int *size)
 {
-    FLACContext *s = avctx->priv_data;
-    int metadata_flag, metadata_type, metadata_size;
-    int tmp = 0, i, j = 0;
-    int16_t *samples = data, *left, *right;
-
-    *data_size = 0;
-
-    s->avctx = avctx;
-
-    init_get_bits(&s->gb, buf, buf_size*8);
-    
-    /* fLaC signature (be) */
-    if (get_bits_long(&s->gb, 32) == bswap_32(ff_get_fourcc("fLaC")))
-    {
-        printf("STREAM HEADER\n");
-        do {
-            metadata_flag = get_bits(&s->gb, 1);
-            metadata_type = get_bits(&s->gb, 7);
-            metadata_size = get_bits_long(&s->gb, 24);
-            
-            printf(" metadata block: flag = %d, type = %d, size = %d\n",
-                metadata_flag, metadata_type,
-                metadata_size);
-
-            switch(metadata_type)
-            {
-                case METADATA_TYPE_STREAMINFO:
-                    metadata_streaminfo(s);
-                    dump_headers(s);
-                    break;
-                default:
-                    while ((metadata_size -= 8) > 0)
-                        skip_bits(&s->gb, 8);
-            }
-        } while(metadata_flag != 1);
-    }
-    else
-    {
-        init_get_bits(&s->gb, buf, buf_size*8);
-        tmp = get_bits(&s->gb, 16);
-        if (tmp == 0xfff8)
-            printf("FRAME HEADER\n");
-
-        if (decode_frame(s) < 0)
-            return -1;
-    }
-    
-#if 0
-    /* fix the channel order here */
-    if (s->order == MID_SIDE)
-    {
-        short *left = samples;
-        short *right = samples + s->blocksize;
-        for (i = 0; i < s->blocksize; i += 2)
-        {
-            uint32_t x = s->decoded[0][i];
-            uint32_t y = s->decoded[0][i+1];
-
-            right[i] = x - (y / 2);
-            left[i] = right[i] + y;
-        }
-        *data_size = 2 * s->blocksize;
-    }
-    else
-    {
-    for (i = 0; i < s->channels; i++)
-    {
-        switch(s->order)
-        {
-            case INDEPENDENT:
-                for (j = 0; j < s->blocksize; j++)
-                    samples[(s->blocksize*i)+j] = s->decoded[i][j];
-                break;
-            case LEFT_SIDE:
-            case RIGHT_SIDE:
-                if (i == 0)
-                    for (j = 0; j < s->blocksize; j++)
-                        samples[(s->blocksize*i)+j] = s->decoded[0][j];
-                else
-                    for (j = 0; j < s->blocksize; j++)
-                        samples[(s->blocksize*i)+j] = s->decoded[0][j] - s->decoded[i][j];
-                break;
-//            case MID_SIDE:
-//                printf("mid-side unsupported\n");
-        }
-        *data_size += s->blocksize;
-    }
-    }
-#else
-    switch(s->order)
-    {
-        case INDEPENDENT:
-            for (i = 0; i < s->channels; i++)
-            {
-                for (j = 0; j < s->blocksize; j++)
-                    *(samples++) = s->decoded[i][j];
-                *data_size += s->blocksize;
-            }
-            break;
-        case LEFT_SIDE:
-            assert(s->channels == 2);
-            for (i = 0; i < s->blocksize; i++)
-            {
-                *(samples++) = s->decoded[0][i];
-                *(samples++) = s->decoded[0][i] - s->decoded[1][i];
-            }
-            *data_size = 2*s->blocksize;
-            break;
-        case RIGHT_SIDE:
-            assert(s->channels == 2);
-            for (i = 0; i < s->blocksize; i++)
-            {
-                *(samples++) = s->decoded[0][i] + s->decoded[1][i];
-                *(samples++) = s->decoded[1][i];
-            }
-            *data_size = 2*s->blocksize;
-            break;
-        case MID_SIDE:
-            assert(s->channels == 2);
-            for (i = 0; i < s->blocksize; i++)
-            {
-                int16_t mid, side;
-                mid = s->decoded[0][i];
-                side = s->decoded[1][i];
-                
-                mid <<= 1;
-                if (side & 1)
-                    mid++;
-                *(samples++) = (mid + side) >> 1;
-                *(samples++) = (mid - side) >> 1;
-            }
-            *data_size = 2*s->blocksize;
-            break;
-    }
-#endif
-
-//    *data_size = (int8_t *)samples - (int8_t *)data;
-    printf("data size: %d\n", *data_size);
-
-    s->last_blocksize = s->blocksize;
-
-    return (get_bits_count(&s->gb)+7)/8;
-}
-
-static int flac_decode_close(AVCodecContext *avctx)
-{
-    FLACContext *s = avctx->priv_data;
-    int i;
-    
-    for (i = 0; i < s->channels; i++)
-    {
-        if (s->decoded[i])
-            av_free(s->decoded[i]);
-        if (s->residual[i])
-            av_free(s->residual[i]);
-    }
-    
-    return 0;
+    flac_parse_block_header(block_header, last, type, size);
 }
-
-AVCodec flac_decoder = {
-    "flac",
-    CODEC_TYPE_AUDIO,
-    CODEC_ID_FLAC,
-    sizeof(FLACContext),
-    flac_decode_init,
-    NULL,
-    flac_decode_close,
-    flac_decode_frame,
-};
+#endif