static int tta_decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPacket *avpkt) { const uint8_t *buf = avpkt->data; int buf_size = avpkt->size; TTAContext *s = avctx->priv_data; int i; init_get_bits(&s->gb, buf, buf_size*8); { int cur_chan = 0, framelen = s->frame_length; int32_t *p; if (*data_size < (framelen * s->channels * 2)) { av_log(avctx, AV_LOG_ERROR, "Output buffer size is too small.\n"); return -1; } // FIXME: seeking s->total_frames--; if (!s->total_frames && s->last_frame_length) framelen = s->last_frame_length; // init per channel states for (i = 0; i < s->channels; i++) { s->ch_ctx[i].predictor = 0; ttafilter_init(&s->ch_ctx[i].filter, ttafilter_configs[s->bps-1][0], ttafilter_configs[s->bps-1][1]); rice_init(&s->ch_ctx[i].rice, 10, 10); } for (p = s->decode_buffer; p < s->decode_buffer + (framelen * s->channels); p++) { int32_t *predictor = &s->ch_ctx[cur_chan].predictor; TTAFilter *filter = &s->ch_ctx[cur_chan].filter; TTARice *rice = &s->ch_ctx[cur_chan].rice; uint32_t unary, depth, k; int32_t value; unary = tta_get_unary(&s->gb); if (unary == 0) { depth = 0; k = rice->k0; } else { depth = 1; k = rice->k1; unary--; } if (get_bits_left(&s->gb) < k) return -1; if (k) { if (k > MIN_CACHE_BITS) return -1; value = (unary << k) + get_bits(&s->gb, k); } else value = unary; // FIXME: copy paste from original switch (depth) { case 1: rice->sum1 += value - (rice->sum1 >> 4); if (rice->k1 > 0 && rice->sum1 < shift_16[rice->k1]) rice->k1--; else if(rice->sum1 > shift_16[rice->k1 + 1]) rice->k1++; value += shift_1[rice->k0]; default: rice->sum0 += value - (rice->sum0 >> 4); if (rice->k0 > 0 && rice->sum0 < shift_16[rice->k0]) rice->k0--; else if(rice->sum0 > shift_16[rice->k0 + 1]) rice->k0++; } // extract coded value #define UNFOLD(x) (((x)&1) ? (++(x)>>1) : (-(x)>>1)) *p = UNFOLD(value); // run hybrid filter ttafilter_process(filter, p, 0); // fixed order prediction #define PRED(x, k) (int32_t)((((uint64_t)x << k) - x) >> k) switch (s->bps) { case 1: *p += PRED(*predictor, 4); break; case 2: case 3: *p += PRED(*predictor, 5); break; case 4: *p += *predictor; break; } *predictor = *p; // flip channels if (cur_chan < (s->channels-1)) cur_chan++; else { // decorrelate in case of stereo integer if (s->channels > 1) { int32_t *r = p - 1; for (*p += *r / 2; r > p - s->channels; r--) *r = *(r + 1) - *r; } cur_chan = 0; } } if (get_bits_left(&s->gb) < 32) return -1; skip_bits(&s->gb, 32); // frame crc // convert to output buffer switch(s->bps) { case 2: { uint16_t *samples = data; for (p = s->decode_buffer; p < s->decode_buffer + (framelen * s->channels); p++) { *samples++ = *p; } *data_size = (uint8_t *)samples - (uint8_t *)data; break; } default: av_log(s->avctx, AV_LOG_ERROR, "Error, only 16bit samples supported!\n"); } } return buf_size; }