-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];
- unsigned shift = aacenc_is_dual_rate_sbr(params);
-
- switch (params->profile) {
- case AOT_SBR:
- case AOT_PS:
- if (!shift)
- break;
- 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 << shift) << 3;
- if (params->profile == AOT_SBR) {
- *outsize = ascsize + 3;
- return 0;
- }
- 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;
- return 0;
- }
- if (*outsize < ascsize)
- return -1;
- memcpy(outasc, asc, ascsize);
- *outsize = ascsize;
- return 0;
-}
-