]> git.sesse.net Git - ffmpeg/blobdiff - libavcodec/alac.c
snow altivec is broken
[ffmpeg] / libavcodec / alac.c
index d6386b40e045f1a0a4340e4ab4737beb0bcfa9e9..b9edf596a9cdae858366a3c241c2c2805262cd51 100644 (file)
@@ -1,7 +1,6 @@
 /*
  * ALAC (Apple Lossless Audio Codec) decoder
  * Copyright (c) 2005 David Hammerton
- * All rights reserved.
  *
  * This file is part of FFmpeg.
  *
 
 #include "avcodec.h"
 #include "bitstream.h"
+#include "bytestream.h"
 
 #define ALAC_EXTRADATA_SIZE 36
+#define MAX_CHANNELS 2
 
 typedef struct {
 
@@ -71,11 +72,9 @@ typedef struct {
     int bytespersample;
 
     /* buffers */
-    int32_t *predicterror_buffer_a;
-    int32_t *predicterror_buffer_b;
+    int32_t *predicterror_buffer[MAX_CHANNELS];
 
-    int32_t *outputsamples_buffer_a;
-    int32_t *outputsamples_buffer_b;
+    int32_t *outputsamples_buffer[MAX_CHANNELS];
 
     /* stuff from setinfo */
     uint32_t setinfo_max_samples_per_frame; /* 0x1000 = 4096 */    /* max samples per frame? */
@@ -86,8 +85,8 @@ typedef struct {
     uint8_t setinfo_rice_kmodifier; /* 0x0e */
     uint8_t setinfo_7f; /* 0x02 */
     uint16_t setinfo_80; /* 0x00ff */
-    uint32_t setinfo_82; /* 0x000020e7 */
-    uint32_t setinfo_86; /* 0x00069fe4 */
+    uint32_t setinfo_82; /* 0x000020e7 */ /* max sample size?? */
+    uint32_t setinfo_86; /* 0x00069fe4 */ /* bit rate (average)?? */
     uint32_t setinfo_8a_rate; /* 0x0000ac44 */
     /* end setinfo stuff */
 
@@ -95,11 +94,14 @@ typedef struct {
 
 static void allocate_buffers(ALACContext *alac)
 {
-    alac->predicterror_buffer_a = av_malloc(alac->setinfo_max_samples_per_frame * 4);
-    alac->predicterror_buffer_b = av_malloc(alac->setinfo_max_samples_per_frame * 4);
+    int chan;
+    for (chan = 0; chan < MAX_CHANNELS; chan++) {
+        alac->predicterror_buffer[chan] =
+            av_malloc(alac->setinfo_max_samples_per_frame * 4);
 
-    alac->outputsamples_buffer_a = av_malloc(alac->setinfo_max_samples_per_frame * 4);
-    alac->outputsamples_buffer_b = av_malloc(alac->setinfo_max_samples_per_frame * 4);
+        alac->outputsamples_buffer[chan] =
+            av_malloc(alac->setinfo_max_samples_per_frame * 4);
+    }
 }
 
 static int alac_set_info(ALACContext *alac)
@@ -110,43 +112,36 @@ static int alac_set_info(ALACContext *alac)
     ptr += 4; /* alac */
     ptr += 4; /* 0 ? */
 
-    if(BE_32(ptr) >= UINT_MAX/4){
+    if(AV_RB32(ptr) >= UINT_MAX/4){
         av_log(alac->avctx, AV_LOG_ERROR, "setinfo_max_samples_per_frame too large\n");
         return -1;
     }
-    alac->setinfo_max_samples_per_frame = BE_32(ptr); /* buffer size / 2 ? */
-    ptr += 4;
-    alac->setinfo_7a = *ptr++;
-    alac->setinfo_sample_size = *ptr++;
-    alac->setinfo_rice_historymult = *ptr++;
-    alac->setinfo_rice_initialhistory = *ptr++;
-    alac->setinfo_rice_kmodifier = *ptr++;
-    alac->setinfo_7f = *ptr++; // channels?
-    alac->setinfo_80 = BE_16(ptr);
-    ptr += 2;
-    alac->setinfo_82 = BE_32(ptr); // max coded frame size
-    ptr += 4;
-    alac->setinfo_86 = BE_32(ptr); // bitrate ?
-    ptr += 4;
-    alac->setinfo_8a_rate = BE_32(ptr); // samplerate
-    ptr += 4;
+
+    /* buffer size / 2 ? */
+    alac->setinfo_max_samples_per_frame = bytestream_get_be32(&ptr);
+    alac->setinfo_7a                    = *ptr++;
+    alac->setinfo_sample_size           = *ptr++;
+    alac->setinfo_rice_historymult      = *ptr++;
+    alac->setinfo_rice_initialhistory   = *ptr++;
+    alac->setinfo_rice_kmodifier        = *ptr++;
+    /* channels? */
+    alac->setinfo_7f                    = *ptr++;
+    alac->setinfo_80                    = bytestream_get_be16(&ptr);
+    /* max coded frame size */
+    alac->setinfo_82                    = bytestream_get_be32(&ptr);
+    /* bitrate ? */
+    alac->setinfo_86                    = bytestream_get_be32(&ptr);
+    /* samplerate */
+    alac->setinfo_8a_rate               = bytestream_get_be32(&ptr);
 
     allocate_buffers(alac);
 
     return 0;
 }
 
-/* hideously inefficient. could use a bitmask search,
- * alternatively bsr on x86,
- */
-static int count_leading_zeros(int32_t input)
+static inline int count_leading_zeros(int32_t input)
 {
-    int i = 0;
-    while (!(0x80000000 & input) && i < 32) {
-        i++;
-        input = input << 1;
-    }
-    return i;
+    return 31-av_log2(input);
 }
 
 static void bastardized_rice_decompress(ALACContext *alac,
@@ -175,7 +170,7 @@ static void bastardized_rice_decompress(ALACContext *alac,
 
 
         if (x > 8) { /* RICE THRESHOLD */
-          /* use alternative encoding */
+            /* use alternative encoding */
             int32_t value;
 
             value = get_bits(&alac->gb, readsamplesize);
@@ -186,7 +181,7 @@ static void bastardized_rice_decompress(ALACContext *alac,
 
             x = value;
         } else {
-          /* standard rice encoding */
+            /* standard rice encoding */
             int extrabits;
             int k; /* size of extra bits */
 
@@ -206,10 +201,9 @@ static void bastardized_rice_decompress(ALACContext *alac,
 
                 if (extrabits > 1) {
                     x += extrabits - 1;
-                    get_bits(&alac->gb, k);
-                } else {
-                    get_bits(&alac->gb, k - 1);
-                }
+                    skip_bits(&alac->gb, k);
+                } else
+                    skip_bits(&alac->gb, k - 1);
             }
         }
 
@@ -222,8 +216,8 @@ static void bastardized_rice_decompress(ALACContext *alac,
         sign_modifier = 0;
 
         /* now update the history */
-        history += (x_modified * rice_historymult)
-                 - ((history * rice_historymult) >> 9);
+        history += x_modified * rice_historymult
+                   - ((history * rice_historymult) >> 9);
 
         if (x_modified > 0xffff)
             history = 0xffff;
@@ -256,16 +250,15 @@ static void bastardized_rice_decompress(ALACContext *alac,
                 if (extrabits < 2) {
                     x = 1 - extrabits;
                     block_size += x;
-                    get_bits(&alac->gb, k - 1);
+                    skip_bits(&alac->gb, k - 1);
                 } else {
-                    get_bits(&alac->gb, k);
+                    skip_bits(&alac->gb, k);
                 }
             }
 
             if (block_size > 0) {
                 memset(&output_buffer[output_count+1], 0, block_size * 4);
                 output_count += block_size;
-
             }
 
             if (block_size > 0xffff)
@@ -297,7 +290,9 @@ static void predictor_decompress_fir_adapt(int32_t *error_buffer,
     *buffer_out = *error_buffer;
 
     if (!predictor_coef_num) {
-        if (output_size <= 1) return;
+        if (output_size <= 1)
+            return;
+
         memcpy(buffer_out+1, error_buffer+1, (output_size-1) * 4);
         return;
     }
@@ -306,31 +301,29 @@ static void predictor_decompress_fir_adapt(int32_t *error_buffer,
       /* second-best case scenario for fir decompression,
        * error describes a small difference from the previous sample only
        */
-        if (output_size <= 1) return;
+        if (output_size <= 1)
+            return;
         for (i = 0; i < output_size - 1; i++) {
             int32_t prev_value;
             int32_t error_value;
 
             prev_value = buffer_out[i];
             error_value = error_buffer[i+1];
-            buffer_out[i+1] = SIGN_EXTENDED32((prev_value + error_value), readsamplesize);
+            buffer_out[i+1] =
+                SIGN_EXTENDED32((prev_value + error_value), readsamplesize);
         }
         return;
     }
 
     /* read warm-up samples */
-    if (predictor_coef_num > 0) {
-        int i;
+    if (predictor_coef_num > 0)
         for (i = 0; i < predictor_coef_num; i++) {
             int32_t val;
 
             val = buffer_out[i] + error_buffer[i+1];
-
             val = SIGN_EXTENDED32(val, readsamplesize);
-
             buffer_out[i+1] = val;
         }
-    }
 
 #if 0
     /* 4 and 8 are very common cases (the only ones i've seen). these
@@ -347,12 +340,9 @@ static void predictor_decompress_fir_adapt(int32_t *error_buffer,
     }
 #endif
 
-
     /* general case */
     if (predictor_coef_num > 0) {
-        for (i = predictor_coef_num + 1;
-             i < output_size;
-             i++) {
+        for (i = predictor_coef_num + 1; i < output_size; i++) {
             int j;
             int sum = 0;
             int outval;
@@ -409,32 +399,29 @@ static void predictor_decompress_fir_adapt(int32_t *error_buffer,
     }
 }
 
-static void deinterlace_16(int32_t *buffer_a, int32_t *buffer_b,
-                    int16_t *buffer_out,
-                    int numchannels, int numsamples,
-                    uint8_t interlacing_shift,
-                    uint8_t interlacing_leftweight)
+static void reconstruct_stereo_16(int32_t *buffer[MAX_CHANNELS],
+                                  int16_t *buffer_out,
+                                  int numchannels, int numsamples,
+                                  uint8_t interlacing_shift,
+                                  uint8_t interlacing_leftweight)
 {
     int i;
-    if (numsamples <= 0) return;
+    if (numsamples <= 0)
+        return;
 
     /* weighted interlacing */
     if (interlacing_leftweight) {
         for (i = 0; i < numsamples; i++) {
-            int32_t difference, midright;
-            int16_t left;
-            int16_t right;
-
-            midright = buffer_a[i];
-            difference = buffer_b[i];
+            int32_t a, b;
 
+            a = buffer[0][i];
+            b = buffer[1][i];
 
-            right = midright - ((difference * interlacing_leftweight) >> interlacing_shift);
-            left = (midright - ((difference * interlacing_leftweight) >> interlacing_shift))
-                 + difference;
+            a -= (b * interlacing_leftweight) >> interlacing_shift;
+            b += a;
 
-            buffer_out[i*numchannels] = left;
-            buffer_out[i*numchannels + 1] = right;
+            buffer_out[i*numchannels] = b;
+            buffer_out[i*numchannels + 1] = a;
         }
 
         return;
@@ -444,8 +431,8 @@ static void deinterlace_16(int32_t *buffer_a, int32_t *buffer_b,
     for (i = 0; i < numsamples; i++) {
         int16_t left, right;
 
-        left = buffer_a[i];
-        right = buffer_b[i];
+        left = buffer[0][i];
+        right = buffer[1][i];
 
         buffer_out[i*numchannels] = left;
         buffer_out[i*numchannels + 1] = right;
@@ -460,6 +447,12 @@ static int alac_decode_frame(AVCodecContext *avctx,
 
     int channels;
     int32_t outputsamples;
+    int hassize;
+    int readsamplesize;
+    int wasted_bytes;
+    int isnotcompressed;
+    uint8_t interlacing_shift;
+    uint8_t interlacing_leftweight;
 
     /* short-circuit null buffers */
     if (!inbuffer || !input_buffer_size)
@@ -472,122 +465,118 @@ static int alac_decode_frame(AVCodecContext *avctx,
                 ALAC_EXTRADATA_SIZE);
             return input_buffer_size;
         }
-        alac_set_info(alac);
+        if (alac_set_info(alac)) {
+            av_log(avctx, AV_LOG_ERROR, "alac: set_info failed\n");
+            return input_buffer_size;
+        }
         alac->context_initialized = 1;
     }
 
-    outputsamples = alac->setinfo_max_samples_per_frame;
-
     init_get_bits(&alac->gb, inbuffer, input_buffer_size * 8);
 
-    channels = get_bits(&alac->gb, 3);
-
-    *outputsize = outputsamples * alac->bytespersample;
-
-    switch(channels) {
-    case 0: { /* 1 channel */
-        int hassize;
-        int isnotcompressed;
-        int readsamplesize;
-
-        int wasted_bytes;
-        int ricemodifier;
-
+    channels = get_bits(&alac->gb, 3) + 1;
+    if (channels > MAX_CHANNELS) {
+        av_log(avctx, AV_LOG_ERROR, "channels > %d not supported\n",
+               MAX_CHANNELS);
+        return input_buffer_size;
+    }
 
-        /* 2^result = something to do with output waiting.
-         * perhaps matters if we read > 1 frame in a pass?
-         */
-        get_bits(&alac->gb, 4);
+    /* 2^result = something to do with output waiting.
+     * perhaps matters if we read > 1 frame in a pass?
+     */
+    skip_bits(&alac->gb, 4);
 
-        get_bits(&alac->gb, 12); /* unknown, skip 12 bits */
+    skip_bits(&alac->gb, 12); /* unknown, skip 12 bits */
 
-        hassize = get_bits(&alac->gb, 1); /* the output sample size is stored soon */
+    /* the output sample size is stored soon */
+    hassize = get_bits1(&alac->gb);
 
-        wasted_bytes = get_bits(&alac->gb, 2); /* unknown ? */
+    wasted_bytes = get_bits(&alac->gb, 2); /* unknown ? */
 
-        isnotcompressed = get_bits(&alac->gb, 1); /* whether the frame is compressed */
+    /* whether the frame is compressed */
+    isnotcompressed = get_bits1(&alac->gb);
 
-        if (hassize) {
-            /* now read the number of samples,
-             * as a 32bit integer */
-            outputsamples = get_bits(&alac->gb, 32);
-            *outputsize = outputsamples * alac->bytespersample;
-        }
+    if (hassize) {
+        /* now read the number of samples as a 32bit integer */
+        outputsamples = get_bits(&alac->gb, 32);
+    } else
+        outputsamples = alac->setinfo_max_samples_per_frame;
 
-        readsamplesize = alac->setinfo_sample_size - (wasted_bytes * 8);
+    *outputsize = outputsamples * alac->bytespersample;
+    readsamplesize = alac->setinfo_sample_size - (wasted_bytes * 8) + channels - 1;
 
-        if (!isnotcompressed) {
-         /* so it is compressed */
-            int16_t predictor_coef_table[32];
-            int predictor_coef_num;
-            int prediction_type;
-            int prediction_quantitization;
-            int i;
+    if (!isnotcompressed) {
+        /* so it is compressed */
+        int16_t predictor_coef_table[channels][32];
+        int predictor_coef_num[channels];
+        int prediction_type[channels];
+        int prediction_quantitization[channels];
+        int ricemodifier[channels];
+        int i, chan;
 
-            /* FIXME: skip 16 bits, not sure what they are. seem to be used in
-             * two channel case */
-            get_bits(&alac->gb, 8);
-            get_bits(&alac->gb, 8);
+        interlacing_shift = get_bits(&alac->gb, 8);
+        interlacing_leftweight = get_bits(&alac->gb, 8);
 
-            prediction_type = get_bits(&alac->gb, 4);
-            prediction_quantitization = get_bits(&alac->gb, 4);
+        for (chan = 0; chan < channels; chan++) {
+            prediction_type[chan] = get_bits(&alac->gb, 4);
+            prediction_quantitization[chan] = get_bits(&alac->gb, 4);
 
-            ricemodifier = get_bits(&alac->gb, 3);
-            predictor_coef_num = get_bits(&alac->gb, 5);
+            ricemodifier[chan] = get_bits(&alac->gb, 3);
+            predictor_coef_num[chan] = get_bits(&alac->gb, 5);
 
             /* read the predictor table */
-            for (i = 0; i < predictor_coef_num; i++) {
-                predictor_coef_table[i] = (int16_t)get_bits(&alac->gb, 16);
-            }
+            for (i = 0; i < predictor_coef_num[chan]; i++)
+                predictor_coef_table[chan][i] = (int16_t)get_bits(&alac->gb, 16);
+        }
 
-            if (wasted_bytes) {
-                /* these bytes seem to have something to do with
-                 * > 2 channel files.
-                 */
-                av_log(avctx, AV_LOG_ERROR, "FIXME: unimplemented, unhandling of wasted_bytes\n");
-            }
+        if (wasted_bytes)
+            av_log(avctx, AV_LOG_ERROR, "FIXME: unimplemented, unhandling of wasted_bytes\n");
 
+        for (chan = 0; chan < channels; chan++) {
             bastardized_rice_decompress(alac,
-                                        alac->predicterror_buffer_a,
+                                        alac->predicterror_buffer[chan],
                                         outputsamples,
                                         readsamplesize,
                                         alac->setinfo_rice_initialhistory,
                                         alac->setinfo_rice_kmodifier,
-                                        ricemodifier * alac->setinfo_rice_historymult / 4,
+                                        ricemodifier[chan] * alac->setinfo_rice_historymult / 4,
                                         (1 << alac->setinfo_rice_kmodifier) - 1);
 
-            if (prediction_type == 0) {
-              /* adaptive fir */
-                predictor_decompress_fir_adapt(alac->predicterror_buffer_a,
-                                               alac->outputsamples_buffer_a,
+            if (prediction_type[chan] == 0) {
+                /* adaptive fir */
+                predictor_decompress_fir_adapt(alac->predicterror_buffer[chan],
+                                               alac->outputsamples_buffer[chan],
                                                outputsamples,
                                                readsamplesize,
-                                               predictor_coef_table,
-                                               predictor_coef_num,
-                                               prediction_quantitization);
+                                               predictor_coef_table[chan],
+                                               predictor_coef_num[chan],
+                                               prediction_quantitization[chan]);
             } else {
-                av_log(avctx, AV_LOG_ERROR, "FIXME: unhandled prediction type: %i\n", prediction_type);
-                /* i think the only other prediction type (or perhaps this is just a
-                 * boolean?) runs adaptive fir twice.. like:
+                av_log(avctx, AV_LOG_ERROR, "FIXME: unhandled prediction type: %i\n", prediction_type[chan]);
+                /* I think the only other prediction type (or perhaps this is
+                 * just a boolean?) runs adaptive fir twice.. like:
                  * predictor_decompress_fir_adapt(predictor_error, tempout, ...)
                  * predictor_decompress_fir_adapt(predictor_error, outputsamples ...)
                  * little strange..
                  */
             }
-
-        } else {
-          /* not compressed, easy case */
-            if (readsamplesize <= 16) {
-                int i;
+        }
+    } else {
+        /* not compressed, easy case */
+        if (alac->setinfo_sample_size <= 16) {
+            int i, chan;
+            for (chan = 0; chan < channels; chan++)
                 for (i = 0; i < outputsamples; i++) {
-                    int32_t audiobits = get_bits(&alac->gb, readsamplesize);
+                    int32_t audiobits;
 
+                    audiobits = get_bits(&alac->gb, alac->setinfo_sample_size);
                     audiobits = SIGN_EXTENDED32(audiobits, readsamplesize);
 
-                    alac->outputsamples_buffer_a[i] = audiobits;
+                    alac->outputsamples_buffer[chan][i] = audiobits;
                 }
-            } else {
-                int i;
+        } else {
+            int i, chan;
+            for (chan = 0; chan < channels; chan++)
                 for (i = 0; i < outputsamples; i++) {
                     int32_t audiobits;
 
@@ -595,224 +584,41 @@ static int alac_decode_frame(AVCodecContext *avctx,
                     /* special case of sign extension..
                      * as we'll be ORing the low 16bits into this */
                     audiobits = audiobits << 16;
-                    audiobits = audiobits >> (32 - readsamplesize);
-
-                    audiobits |= get_bits(&alac->gb, readsamplesize - 16);
+                    audiobits = audiobits >> (32 - alac->setinfo_sample_size);
+                    audiobits |= get_bits(&alac->gb, alac->setinfo_sample_size - 16);
 
-                    alac->outputsamples_buffer_a[i] = audiobits;
+                    alac->outputsamples_buffer[chan][i] = audiobits;
                 }
-            }
-            /* wasted_bytes = 0; // unused */
         }
+        /* wasted_bytes = 0; */
+        interlacing_shift = 0;
+        interlacing_leftweight = 0;
+    }
 
-        switch(alac->setinfo_sample_size) {
-        case 16: {
+    switch(alac->setinfo_sample_size) {
+    case 16:
+        if (channels == 2) {
+            reconstruct_stereo_16(alac->outputsamples_buffer,
+                                  (int16_t*)outbuffer,
+                                  alac->numchannels,
+                                  outputsamples,
+                                  interlacing_shift,
+                                  interlacing_leftweight);
+        } else {
             int i;
             for (i = 0; i < outputsamples; i++) {
-                int16_t sample = alac->outputsamples_buffer_a[i];
+                int16_t sample = alac->outputsamples_buffer[0][i];
                 ((int16_t*)outbuffer)[i * alac->numchannels] = sample;
             }
-            break;
-        }
-        case 20:
-        case 24:
-        case 32:
-            av_log(avctx, AV_LOG_ERROR, "FIXME: unimplemented sample size %i\n", alac->setinfo_sample_size);
-            break;
-        default:
-            break;
         }
         break;
-    }
-    case 1: { /* 2 channels */
-        int hassize;
-        int isnotcompressed;
-        int readsamplesize;
-
-        int wasted_bytes;
-
-        uint8_t interlacing_shift;
-        uint8_t interlacing_leftweight;
-
-        /* 2^result = something to do with output waiting.
-         * perhaps matters if we read > 1 frame in a pass?
-         */
-        get_bits(&alac->gb, 4);
-
-        get_bits(&alac->gb, 12); /* unknown, skip 12 bits */
-
-        hassize = get_bits(&alac->gb, 1); /* the output sample size is stored soon */
-
-        wasted_bytes = get_bits(&alac->gb, 2); /* unknown ? */
-
-        isnotcompressed = get_bits(&alac->gb, 1); /* whether the frame is compressed */
-
-        if (hassize) {
-            /* now read the number of samples,
-             * as a 32bit integer */
-            outputsamples = get_bits(&alac->gb, 32);
-            *outputsize = outputsamples * alac->bytespersample;
-        }
-
-        readsamplesize = alac->setinfo_sample_size - (wasted_bytes * 8) + 1;
-
-        if (!isnotcompressed) {
-         /* compressed */
-            int16_t predictor_coef_table_a[32];
-            int predictor_coef_num_a;
-            int prediction_type_a;
-            int prediction_quantitization_a;
-            int ricemodifier_a;
-
-            int16_t predictor_coef_table_b[32];
-            int predictor_coef_num_b;
-            int prediction_type_b;
-            int prediction_quantitization_b;
-            int ricemodifier_b;
-
-            int i;
-
-            interlacing_shift = get_bits(&alac->gb, 8);
-            interlacing_leftweight = get_bits(&alac->gb, 8);
-
-            /******** channel 1 ***********/
-            prediction_type_a = get_bits(&alac->gb, 4);
-            prediction_quantitization_a = get_bits(&alac->gb, 4);
-
-            ricemodifier_a = get_bits(&alac->gb, 3);
-            predictor_coef_num_a = get_bits(&alac->gb, 5);
-
-            /* read the predictor table */
-            for (i = 0; i < predictor_coef_num_a; i++) {
-                predictor_coef_table_a[i] = (int16_t)get_bits(&alac->gb, 16);
-            }
-
-            /******** channel 2 *********/
-            prediction_type_b = get_bits(&alac->gb, 4);
-            prediction_quantitization_b = get_bits(&alac->gb, 4);
-
-            ricemodifier_b = get_bits(&alac->gb, 3);
-            predictor_coef_num_b = get_bits(&alac->gb, 5);
-
-            /* read the predictor table */
-            for (i = 0; i < predictor_coef_num_b; i++) {
-                predictor_coef_table_b[i] = (int16_t)get_bits(&alac->gb, 16);
-            }
-
-            /*********************/
-            if (wasted_bytes) {
-              /* see mono case */
-                av_log(avctx, AV_LOG_ERROR, "FIXME: unimplemented, unhandling of wasted_bytes\n");
-            }
-
-            /* channel 1 */
-            bastardized_rice_decompress(alac,
-                                        alac->predicterror_buffer_a,
-                                        outputsamples,
-                                        readsamplesize,
-                                        alac->setinfo_rice_initialhistory,
-                                        alac->setinfo_rice_kmodifier,
-                                        ricemodifier_a * alac->setinfo_rice_historymult / 4,
-                                        (1 << alac->setinfo_rice_kmodifier) - 1);
-
-            if (prediction_type_a == 0) {
-              /* adaptive fir */
-                predictor_decompress_fir_adapt(alac->predicterror_buffer_a,
-                                               alac->outputsamples_buffer_a,
-                                               outputsamples,
-                                               readsamplesize,
-                                               predictor_coef_table_a,
-                                               predictor_coef_num_a,
-                                               prediction_quantitization_a);
-            } else {
-              /* see mono case */
-                av_log(avctx, AV_LOG_ERROR, "FIXME: unhandled prediction type: %i\n", prediction_type_a);
-            }
-
-            /* channel 2 */
-            bastardized_rice_decompress(alac,
-                                        alac->predicterror_buffer_b,
-                                        outputsamples,
-                                        readsamplesize,
-                                        alac->setinfo_rice_initialhistory,
-                                        alac->setinfo_rice_kmodifier,
-                                        ricemodifier_b * alac->setinfo_rice_historymult / 4,
-                                        (1 << alac->setinfo_rice_kmodifier) - 1);
-
-            if (prediction_type_b == 0) {
-              /* adaptive fir */
-                predictor_decompress_fir_adapt(alac->predicterror_buffer_b,
-                                               alac->outputsamples_buffer_b,
-                                               outputsamples,
-                                               readsamplesize,
-                                               predictor_coef_table_b,
-                                               predictor_coef_num_b,
-                                               prediction_quantitization_b);
-            } else {
-                av_log(avctx, AV_LOG_ERROR, "FIXME: unhandled prediction type: %i\n", prediction_type_b);
-            }
-        } else {
-         /* not compressed, easy case */
-            if (alac->setinfo_sample_size <= 16) {
-                int i;
-                for (i = 0; i < outputsamples; i++) {
-                    int32_t audiobits_a, audiobits_b;
-
-                    audiobits_a = get_bits(&alac->gb, alac->setinfo_sample_size);
-                    audiobits_b = get_bits(&alac->gb, alac->setinfo_sample_size);
-
-                    audiobits_a = SIGN_EXTENDED32(audiobits_a, alac->setinfo_sample_size);
-                    audiobits_b = SIGN_EXTENDED32(audiobits_b, alac->setinfo_sample_size);
-
-                    alac->outputsamples_buffer_a[i] = audiobits_a;
-                    alac->outputsamples_buffer_b[i] = audiobits_b;
-                }
-            } else {
-                int i;
-                for (i = 0; i < outputsamples; i++) {
-                    int32_t audiobits_a, audiobits_b;
-
-                    audiobits_a = get_bits(&alac->gb, 16);
-                    audiobits_a = audiobits_a << 16;
-                    audiobits_a = audiobits_a >> (32 - alac->setinfo_sample_size);
-                    audiobits_a |= get_bits(&alac->gb, alac->setinfo_sample_size - 16);
-
-                    audiobits_b = get_bits(&alac->gb, 16);
-                    audiobits_b = audiobits_b << 16;
-                    audiobits_b = audiobits_b >> (32 - alac->setinfo_sample_size);
-                    audiobits_b |= get_bits(&alac->gb, alac->setinfo_sample_size - 16);
-
-                    alac->outputsamples_buffer_a[i] = audiobits_a;
-                    alac->outputsamples_buffer_b[i] = audiobits_b;
-                }
-            }
-            /* wasted_bytes = 0; */
-            interlacing_shift = 0;
-            interlacing_leftweight = 0;
-        }
-
-        switch(alac->setinfo_sample_size) {
-        case 16: {
-            deinterlace_16(alac->outputsamples_buffer_a,
-                           alac->outputsamples_buffer_b,
-                           (int16_t*)outbuffer,
-                           alac->numchannels,
-                           outputsamples,
-                           interlacing_shift,
-                           interlacing_leftweight);
-            break;
-        }
-        case 20:
-        case 24:
-        case 32:
-            av_log(avctx, AV_LOG_ERROR, "FIXME: unimplemented sample size %i\n", alac->setinfo_sample_size);
-            break;
-        default:
-            break;
-        }
-
+    case 20:
+    case 24:
+    case 32:
+        av_log(avctx, AV_LOG_ERROR, "FIXME: unimplemented sample size %i\n", alac->setinfo_sample_size);
+        break;
+    default:
         break;
-    }
     }
 
     return input_buffer_size;
@@ -835,11 +641,11 @@ static int alac_decode_close(AVCodecContext *avctx)
 {
     ALACContext *alac = avctx->priv_data;
 
-    av_free(alac->predicterror_buffer_a);
-    av_free(alac->predicterror_buffer_b);
-
-    av_free(alac->outputsamples_buffer_a);
-    av_free(alac->outputsamples_buffer_b);
+    int chan;
+    for (chan = 0; chan < MAX_CHANNELS; chan++) {
+        av_free(alac->predicterror_buffer[chan]);
+        av_free(alac->outputsamples_buffer[chan]);
+    }
 
     return 0;
 }