static int dv_extract_audio(uint8_t* frame, uint8_t* ppcm[4], const DVprofile *sys) { int size, chan, i, j, d, of, smpls, freq, quant, half_ch; uint16_t lc, rc; const uint8_t* as_pack; uint8_t *pcm, ipcm; as_pack = dv_extract_pack(frame, dv_audio_source); if (!as_pack) /* No audio ? */ return 0; smpls = as_pack[1] & 0x3f; /* samples in this frame - min. samples */ freq = (as_pack[4] >> 3) & 0x07; /* 0 - 48kHz, 1 - 44,1kHz, 2 - 32kHz */ quant = as_pack[4] & 0x07; /* 0 - 16bit linear, 1 - 12bit nonlinear */ if (quant > 1) return -1; /* unsupported quantization */ size = (sys->audio_min_samples[freq] + smpls) * 4; /* 2ch, 2bytes */ half_ch = sys->difseg_size / 2; /* We work with 720p frames split in half, thus even frames have * channels 0,1 and odd 2,3. */ ipcm = (sys->height == 720 && !(frame[1] & 0x0C)) ? 2 : 0; pcm = ppcm[ipcm++]; /* for each DIF channel */ for (chan = 0; chan < sys->n_difchan; chan++) { /* for each DIF segment */ for (i = 0; i < sys->difseg_size; i++) { frame += 6 * 80; /* skip DIF segment header */ if (quant == 1 && i == half_ch) { /* next stereo channel (12bit mode only) */ pcm = ppcm[ipcm++]; if (!pcm) break; } /* for each AV sequence */ for (j = 0; j < 9; j++) { for (d = 8; d < 80; d += 2) { if (quant == 0) { /* 16bit quantization */ of = sys->audio_shuffle[i][j] + (d - 8) / 2 * sys->audio_stride; if (of*2 >= size) continue; pcm[of*2] = frame[d+1]; // FIXME: maybe we have to admit pcm[of*2+1] = frame[d]; // that DV is a big-endian PCM if (pcm[of*2+1] == 0x80 && pcm[of*2] == 0x00) pcm[of*2+1] = 0; } else { /* 12bit quantization */ lc = ((uint16_t)frame[d] << 4) | ((uint16_t)frame[d+2] >> 4); rc = ((uint16_t)frame[d+1] << 4) | ((uint16_t)frame[d+2] & 0x0f); lc = (lc == 0x800 ? 0 : dv_audio_12to16(lc)); rc = (rc == 0x800 ? 0 : dv_audio_12to16(rc)); of = sys->audio_shuffle[i%half_ch][j] + (d - 8) / 3 * sys->audio_stride; if (of*2 >= size) continue; pcm[of*2] = lc & 0xff; // FIXME: maybe we have to admit pcm[of*2+1] = lc >> 8; // that DV is a big-endian PCM of = sys->audio_shuffle[i%half_ch+half_ch][j] + (d - 8) / 3 * sys->audio_stride; pcm[of*2] = rc & 0xff; // FIXME: maybe we have to admit pcm[of*2+1] = rc >> 8; // that DV is a big-endian PCM ++d; } } frame += 16 * 80; /* 15 Video DIFs + 1 Audio DIF */ } } /* next stereo channel (50Mbps and 100Mbps only) */ pcm = ppcm[ipcm++]; if (!pcm) break; } return size; }