Fix issue 123 (Support Magic-carpet fli version,

[ffmpeg] / libavcodec / alac.c

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index 03f9ae3f39e0bf358be22f180e5d9017179afa55..777c720f34753be4a5026c3227c54a64807ccc44 100644 (file)
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -55,6 +55,7 @@
 #include "avcodec.h"
 #include "bitstream.h"
 #include "bytestream.h"
+#include "unary.h"
 
 #define ALAC_EXTRADATA_SIZE 36
 #define MAX_CHANNELS 2
@@ -159,15 +160,12 @@ static void bastardized_rice_decompress(ALACContext *alac,
     int sign_modifier = 0;
 
     for (output_count = 0; output_count < output_size; output_count++) {
-        int32_t x = 0;
+        int32_t x;
         int32_t x_modified;
         int32_t final_val;
 
         /* read x - number of 1s before 0 represent the rice */
-        while (x <= 8 && get_bits1(&alac->gb)) {
-            x++;
-        }
-
+        x = get_unary_0_9(&alac->gb);
 
         if (x > 8) { /* RICE THRESHOLD */
             /* use alternative encoding */
@@ -201,9 +199,9 @@ static void bastardized_rice_decompress(ALACContext *alac,
 
                 if (extrabits > 1) {
                     x += extrabits - 1;
-                    get_bits(&alac->gb, k);
+                    skip_bits(&alac->gb, k);
                 } else
-                    get_bits(&alac->gb, k - 1);
+                    skip_bits(&alac->gb, k - 1);
             }
         }
 
@@ -228,10 +226,7 @@ static void bastardized_rice_decompress(ALACContext *alac,
 
             sign_modifier = 1;
 
-            x = 0;
-            while (x <= 8 && get_bits1(&alac->gb)) {
-                x++;
-            }
+            x = get_unary_0_9(&alac->gb);
 
             if (x > 8) {
                 block_size = get_bits(&alac->gb, 16);
@@ -250,9 +245,9 @@ 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);
                 }
             }
 
@@ -269,12 +264,15 @@ static void bastardized_rice_decompress(ALACContext *alac,
     }
 }
 
-#define SIGN_EXTENDED32(val, bits) ((val << (32 - bits)) >> (32 - bits))
+static inline int32_t extend_sign32(int32_t val, int bits)
+{
+    return (val << (32 - bits)) >> (32 - bits);
+}
 
-#define SIGN_ONLY(v) \
-                     ((v < 0) ? (-1) : \
-                                ((v > 0) ? (1) : \
-                                           (0)))
+static inline int sign_only(int v)
+{
+    return v ? FFSIGN(v) : 0;
+}
 
 static void predictor_decompress_fir_adapt(int32_t *error_buffer,
                                            int32_t *buffer_out,
@@ -310,7 +308,7 @@ static void predictor_decompress_fir_adapt(int32_t *error_buffer,
             prev_value = buffer_out[i];
             error_value = error_buffer[i+1];
             buffer_out[i+1] =
-                SIGN_EXTENDED32((prev_value + error_value), readsamplesize);
+                extend_sign32((prev_value + error_value), readsamplesize);
         }
         return;
     }
@@ -321,7 +319,7 @@ static void predictor_decompress_fir_adapt(int32_t *error_buffer,
             int32_t val;
 
             val = buffer_out[i] + error_buffer[i+1];
-            val = SIGN_EXTENDED32(val, readsamplesize);
+            val = extend_sign32(val, readsamplesize);
             buffer_out[i+1] = val;
         }
 
@@ -356,7 +354,7 @@ static void predictor_decompress_fir_adapt(int32_t *error_buffer,
             outval = (1 << (predictor_quantitization-1)) + sum;
             outval = outval >> predictor_quantitization;
             outval = outval + buffer_out[0] + error_val;
-            outval = SIGN_EXTENDED32(outval, readsamplesize);
+            outval = extend_sign32(outval, readsamplesize);
 
             buffer_out[predictor_coef_num+1] = outval;
 
@@ -365,7 +363,7 @@ static void predictor_decompress_fir_adapt(int32_t *error_buffer,
 
                 while (predictor_num >= 0 && error_val > 0) {
                     int val = buffer_out[0] - buffer_out[predictor_coef_num - predictor_num];
-                    int sign = SIGN_ONLY(val);
+                    int sign = sign_only(val);
 
                     predictor_coef_table[predictor_num] -= sign;
 
@@ -381,7 +379,7 @@ static void predictor_decompress_fir_adapt(int32_t *error_buffer,
 
                 while (predictor_num >= 0 && error_val < 0) {
                     int val = buffer_out[0] - buffer_out[predictor_coef_num - predictor_num];
-                    int sign = - SIGN_ONLY(val);
+                    int sign = - sign_only(val);
 
                     predictor_coef_table[predictor_num] -= sign;
 
@@ -399,11 +397,11 @@ static void predictor_decompress_fir_adapt(int32_t *error_buffer,
     }
 }
 
-static void deinterlace_16(int32_t *buffer[MAX_CHANNELS],
-                           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)
@@ -484,17 +482,17 @@ static int alac_decode_frame(AVCodecContext *avctx,
     /* 2^result = something to do with output waiting.
      * perhaps matters if we read > 1 frame in a pass?
      */
-    get_bits(&alac->gb, 4);
+    skip_bits(&alac->gb, 4);
 
-    get_bits(&alac->gb, 12); /* unknown, skip 12 bits */
+    skip_bits(&alac->gb, 12); /* unknown, skip 12 bits */
 
     /* the output sample size is stored soon */
-    hassize = get_bits(&alac->gb, 1);
+    hassize = get_bits1(&alac->gb);
 
     wasted_bytes = get_bits(&alac->gb, 2); /* unknown ? */
 
     /* whether the frame is compressed */
-    isnotcompressed = get_bits(&alac->gb, 1);
+    isnotcompressed = get_bits1(&alac->gb);
 
     if (hassize) {
         /* now read the number of samples as a 32bit integer */
@@ -529,9 +527,8 @@ static int alac_decode_frame(AVCodecContext *avctx,
                 predictor_coef_table[chan][i] = (int16_t)get_bits(&alac->gb, 16);
         }
 
-        if (wasted_bytes) {
+        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,
@@ -571,7 +568,7 @@ static int alac_decode_frame(AVCodecContext *avctx,
                     int32_t audiobits;
 
                     audiobits = get_bits(&alac->gb, alac->setinfo_sample_size);
-                    audiobits = SIGN_EXTENDED32(audiobits, readsamplesize);
+                    audiobits = extend_sign32(audiobits, readsamplesize);
 
                     alac->outputsamples_buffer[chan][i] = audiobits;
                 }
@@ -597,14 +594,14 @@ static int alac_decode_frame(AVCodecContext *avctx,
     }
 
     switch(alac->setinfo_sample_size) {
-    case 16: {
+    case 16:
         if (channels == 2) {
-            deinterlace_16(alac->outputsamples_buffer,
-                           (int16_t*)outbuffer,
-                           alac->numchannels,
-                           outputsamples,
-                           interlacing_shift,
-                           interlacing_leftweight);
+            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++) {
@@ -613,9 +610,10 @@ static int alac_decode_frame(AVCodecContext *avctx,
             }
         }
         break;
-    }
     case 20:
     case 24:
+        // It is not clear if there exist any encoder that creates 24 bit ALAC
+        // files. iTunes convert 24 bit raw files to 16 bit before encoding.
     case 32:
         av_log(avctx, AV_LOG_ERROR, "FIXME: unimplemented sample size %i\n", alac->setinfo_sample_size);
         break;