X-Git-Url: http://git.ieval.ro/?p=fdkaac.git;a=blobdiff_plain;f=src%2Faacenc.c;h=d25be8a3570a0eb019d1355f14731fc12f3c268c;hp=af9107d32e82630440952d9dbfcd0f8da2757cf7;hb=9b8f9915c2cac2887e52bb38d263f171b5f7d69d;hpb=5ccbfaa710c8d86a59e5d07f10e2667ea3619ab0

diff --git a/src/aacenc.c b/src/aacenc.c
index af9107d..d25be8a 100644
--- a/src/aacenc.c
+++ b/src/aacenc.c
@@ -10,6 +10,7 @@
 #endif
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include "aacenc.h"
 
 int aacenc_is_sbr_active(const aacenc_param_t *params)
@@ -25,6 +26,68 @@ int aacenc_is_sbr_active(const aacenc_param_t *params)
     return 0;
 }
 
+static const unsigned aacenc_sampling_freq_tab[] = {
+    96000, 88200, 64000, 48000, 44100, 32000, 24000, 22050, 
+    16000, 12000, 11025, 8000, 7350, 0, 0, 0
+};
+
+static
+unsigned sampling_freq_index(unsigned rate)
+{
+    unsigned i;
+    for (i = 0; aacenc_sampling_freq_tab[i]; ++i)
+        if (aacenc_sampling_freq_tab[i] == rate)
+            return i;
+    return 0xf;
+}
+
+/*
+ * Append backward compatible SBR/PS signaling to implicit signaling ASC,
+ * if SBR/PS is present.
+ */
+int aacenc_mp4asc(const aacenc_param_t *params,
+                  const uint8_t *asc, uint32_t ascsize,
+                  uint8_t *outasc, uint32_t *outsize)
+{
+    unsigned asc_sfreq = aacenc_sampling_freq_tab[(asc[0]&0x7)<<1 |asc[1]>>7];
+
+    switch (params->profile) {
+    case AOT_SBR:
+    case AOT_PS:
+        if (*outsize < ascsize + 3)
+            return -1;
+        memcpy(outasc, asc, ascsize);
+        /* syncExtensionType:11 (value:0x2b7) */
+        outasc[ascsize+0] = 0x2b << 1;
+        outasc[ascsize+1] = 0x7 << 5;
+        /* extensionAudioObjectType:5 (value:5)*/
+        outasc[ascsize+1] |= 5;
+        /* sbrPresentFlag:1 (value:1) */
+        outasc[ascsize+2] = 0x80;
+        /* extensionSamplingFrequencyIndex:4 */
+        outasc[ascsize+2] |= sampling_freq_index(asc_sfreq << 1) << 3;
+        if (params->profile == AOT_SBR) {
+            *outsize = ascsize + 3;
+            break;
+        }
+        if (*outsize < ascsize + 5)
+            return -1;
+        /* syncExtensionType:11 (value:0x548) */
+        outasc[ascsize+2] |= 0x5;
+        outasc[ascsize+3] = 0x48;
+        /* psPresentFlag:1 (value:1) */
+        outasc[ascsize+4] = 0x80;
+        *outsize = ascsize + 5;
+        break;
+    default:
+        if (*outsize < ascsize)
+            return -1;
+        memcpy(outasc, asc, ascsize);
+        *outsize = ascsize;
+    }
+    return 0;
+}
+
 static
 int aacenc_channel_mode(const pcm_sample_description_t *format)
 {