tta.c

从FFMPEG转换而来的H264解码程序,VC下编译..

	rice->sum1 = shift_16[k1];
}

static const int flt_set[3] = {10, 9, 10};

static void filter_init (fltst *fs, int shift) {
	memset (fs, 0, sizeof(fltst));
	fs->shift = shift;
	fs->round = 1 << (shift - 1);
}

static __inline void memshl (register int *pA, register int *pB) {
	*pA++ = *pB++;
	*pA++ = *pB++;
	*pA++ = *pB++;
	*pA++ = *pB++;
	*pA++ = *pB++;
	*pA++ = *pB++;
	*pA++ = *pB++;
	*pA   = *pB;
}

static __inline void hybrid_filter (fltst *fs, int *in) {
	register int *pA = fs->dl;
	register int *pB = fs->qm;
	register int *pM = fs->dx;
	register int sum = fs->round;

	if (!fs->error) {
		sum += *pA++ * *pB, pB++;
		sum += *pA++ * *pB, pB++;
		sum += *pA++ * *pB, pB++;
		sum += *pA++ * *pB, pB++;
		sum += *pA++ * *pB, pB++;
		sum += *pA++ * *pB, pB++;
		sum += *pA++ * *pB, pB++;
		sum += *pA++ * *pB, pB++; pM += 8;
	} else if (fs->error < 0) {
		sum += *pA++ * (*pB -= *pM++), pB++;
		sum += *pA++ * (*pB -= *pM++), pB++;
		sum += *pA++ * (*pB -= *pM++), pB++;
		sum += *pA++ * (*pB -= *pM++), pB++;
		sum += *pA++ * (*pB -= *pM++), pB++;
		sum += *pA++ * (*pB -= *pM++), pB++;
		sum += *pA++ * (*pB -= *pM++), pB++;
		sum += *pA++ * (*pB -= *pM++), pB++;
	} else {
		sum += *pA++ * (*pB += *pM++), pB++;
		sum += *pA++ * (*pB += *pM++), pB++;
		sum += *pA++ * (*pB += *pM++), pB++;
		sum += *pA++ * (*pB += *pM++), pB++;
		sum += *pA++ * (*pB += *pM++), pB++;
		sum += *pA++ * (*pB += *pM++), pB++;
		sum += *pA++ * (*pB += *pM++), pB++;
		sum += *pA++ * (*pB += *pM++), pB++;
	}

	*(pM-0) = ((*(pA-1) >> 30) | 1) << 2;
	*(pM-1) = ((*(pA-2) >> 30) | 1) << 1;
	*(pM-2) = ((*(pA-3) >> 30) | 1) << 1;
	*(pM-3) = ((*(pA-4) >> 30) | 1);

	fs->error = *in;
	*in += (sum >> fs->shift);
	*pA = *in;

	*(pA-1) = *(pA-0) - *(pA-1);
	*(pA-2) = *(pA-1) - *(pA-2);
	*(pA-3) = *(pA-2) - *(pA-3);

	memshl (fs->dl, fs->dl + 1);
	memshl (fs->dx, fs->dx + 1);
}


static void decoder_init(decoder *tta, int nch, int byte_size) {
	int shift = flt_set[byte_size - 1];
	int i;

	for (i = 0; i < nch; i++) {
		filter_init(&tta[i].fst, shift);
		rice_init(&tta[i].rice, 10, 10);
		tta[i].last = 0;
	}
}

static int set_position (TTAstate *s,unsigned int pos) {
/*
	unsigned int seek_pos;
	if (pos >= fframes) return 0;
	if (!st_state) {
		ttainfo->STATE = FILE_ERROR;
		return -1;
	}

	seek_pos = ttainfo->DATAPOS + seek_table[data_pos = pos];
	if (fseek(ttainfo->HANDLE, seek_pos, SEEK_SET) < 0) {
		ttainfo->STATE = READ_ERROR;
		return -1;
	}
*/
	s->data_cur = 0;
	s->framelen = 0;

	// init bit reader
	init_buffer_read(s);

	return 0;
}

#define PREDICTOR1(x, k)	((int)((((uint64_t)x << k) - x) >> k))
#define DEC(x)			(((x)&1)?(++(x)>>1):(-(x)>>1))

static int tta_decode_frame(AVCodecContext *avctx,
			    void *data, int *data_size,
			    uint8_t *buf, int buf_size)
{
    TTAstate *s = avctx->priv_data;
    unsigned int k, depth, unary, binary;
    uint8_t *p = data;
    int value, res;
    int *prev = s->cache;
    decoder *dec = s->tta;

    s->src=buf;s->srcsize=buf_size;s->readsize=0;

	for (res = 0; p < (uint8_t*)data + s->pcm_buffer_size;) {
		fltst *fst = &dec->fst;
		adapt *rice = &dec->rice;
		int *last = &dec->last;

		if (s->data_cur == s->framelen) {
			//if (data_pos == fframes) break;
			if (s->framelen && done_buffer_read(s)) {
			    if (set_position(s,s->data_pos))
			     return -1;
			    if (res)
			     break;
			}

			/*if (s->data_pos == fframes - 1 && lastlen)
				framelen = lastlen;
			else*/ s->framelen = s->FRAMELEN;

			decoder_init(s->tta, avctx->channels, avctx->bits_per_sample>>3);
			s->data_pos++; s->data_cur = 0;
		}

		// decode Rice unsigned
		//GET_UNARY(unary);
	        unary = 0;
	        while (!(s->bit_cache ^ bit_mask[s->bit_count])) {
		        if (s->bitpos == s->iso_buffers_end) {
			        if (!read(s,s->isobuffers, 1, ISO_BUFFERS_SIZE)) {
			            s->STATE = READ_ERROR;
			            return -1; }
			        s->bitpos = s->isobuffers; }
		        unary += s->bit_count;
		        s->bit_cache = *s->bitpos++;
		        UPDATE_CRC32(s->bit_cache, s->frame_crc32);
		        s->bit_count = 8; }
	        while (s->bit_cache & 1) {
		        unary++;
		        s->bit_cache >>= 1;
		        s->bit_count--; }
	        s->bit_cache >>= 1;
	        s->bit_count--;

		switch (unary) {
		case 0: depth = 0; k = rice->k0; break;
		default:
			depth = 1; k = rice->k1;
			unary--;
		}

		if (k) {
//			GET_BINARY(binary, k);
	                while (s->bit_count < k) {
		                if (s->bitpos == s->iso_buffers_end) {
			                if (!read(s,s->isobuffers, 1, ISO_BUFFERS_SIZE)) {
			                    s->STATE = READ_ERROR;
			                    return -1; }
			                s->bitpos = s->isobuffers; }
		                UPDATE_CRC32(*s->bitpos, s->frame_crc32);
		                s->bit_cache |= *s->bitpos << s->bit_count;
		                s->bit_count += 8;
		                s->bitpos++; }
	                binary = s->bit_cache & bit_mask[k];
	                s->bit_cache >>= k;
	                s->bit_count -= k;
	                s->bit_cache &= bit_mask[s->bit_count];

			value = (unary << k) + binary;
		} else value = unary;

		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 += bit_shift[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++;
		}

		value = DEC(value);

		// decompress stage 1: adaptive hybrid filter
		hybrid_filter(fst, &value);

		// decompress stage 2: fixed order 1 prediction
		switch (avctx->bits_per_sample>>3) {
		case 1: value += PREDICTOR1(*last, 4); break;	// bps 8
		case 2: value += PREDICTOR1(*last, 5); break;	// bps 16
		case 3: value += PREDICTOR1(*last, 5); break;	// bps 24
		} *last = value;

		// check for errors
		if (FFABS(value) > s->maxvalue) {
			unsigned int tail =
				s->pcm_buffer_size / ((avctx->bits_per_sample>>3)* avctx->channels) - res;
			memset(data, 0, s->pcm_buffer_size);
			s->data_cur += tail; res += tail;
			break;
		}

		if (dec < s->tta + (avctx->channels - 1)) {
			*prev++ = value; dec++;
		} else {
			*prev = value;
			if (avctx->channels > 1) {
				int *r = prev - 1;
				for (*prev += *r/2; r >= s->cache; r--)
					*r = *(r + 1) - *r;
				for (r = s->cache; r < prev; r++)
					WRITE_BUFFER(r, (avctx->bits_per_sample>>3), p)
			}
			WRITE_BUFFER(prev, (avctx->bits_per_sample>>3), p)
			prev = s->cache;
			s->data_cur++; res++;
			dec = s->tta;
		}
        }
    *data_size=res*avctx->channels*(avctx->bits_per_sample>>3);
    return s->readsize; //buf_size-s->srcsize;
}

static void tta_flush(AVCodecContext *avctx)
{
    TTAstate *s = avctx->priv_data;
    set_position(s,0);
}

AVCodec tta_decoder = {
    "tta",
    CODEC_TYPE_AUDIO,
    CODEC_ID_TTA,
    sizeof(TTAstate),
    tta_decode_init,
    NULL,
    NULL,
    tta_decode_frame,
    0,
    NULL,
    tta_flush
};