#include "avcodec.h"
#include "bitstream.h"
#include "bytestream.h"
+#include "unary.h"
#define ALAC_EXTRADATA_SIZE 36
#define MAX_CHANNELS 2
return 0;
}
-/* hideously inefficient. could use a bitmask search,
- * alternatively bsr on x86,
- */
-static int count_leading_zeros(int32_t input)
+static inline int count_leading_zeros(int32_t input)
{
- int i = 0;
- while (!(0x80000000 & input) && i < 32) {
- i++;
- input = input << 1;
- }
- return i;
+ return 31-av_log2(input);
}
static void bastardized_rice_decompress(ALACContext *alac,
int sign_modifier = 0;
for (output_count = 0; output_count < output_size; output_count++) {
- int32_t x = 0;
+ int32_t x;
int32_t x_modified;
int32_t final_val;
/* read x - number of 1s before 0 represent the rice */
- while (x <= 8 && get_bits1(&alac->gb)) {
- x++;
- }
-
+ x = get_unary_0_9(&alac->gb);
if (x > 8) { /* RICE THRESHOLD */
- /* use alternative encoding */
+ /* use alternative encoding */
int32_t value;
value = get_bits(&alac->gb, readsamplesize);
x = value;
} else {
- /* standard rice encoding */
+ /* standard rice encoding */
int extrabits;
int k; /* size of extra bits */
if (extrabits > 1) {
x += extrabits - 1;
- get_bits(&alac->gb, k);
- } else {
- get_bits(&alac->gb, k - 1);
- }
+ skip_bits(&alac->gb, k);
+ } else
+ skip_bits(&alac->gb, k - 1);
}
}
sign_modifier = 0;
/* now update the history */
- history += (x_modified * rice_historymult)
- - ((history * rice_historymult) >> 9);
+ history += x_modified * rice_historymult
+ - ((history * rice_historymult) >> 9);
if (x_modified > 0xffff)
history = 0xffff;
sign_modifier = 1;
- x = 0;
- while (x <= 8 && get_bits1(&alac->gb)) {
- x++;
- }
+ x = get_unary_0_9(&alac->gb);
if (x > 8) {
block_size = get_bits(&alac->gb, 16);
if (extrabits < 2) {
x = 1 - extrabits;
block_size += x;
- get_bits(&alac->gb, k - 1);
+ skip_bits(&alac->gb, k - 1);
} else {
- get_bits(&alac->gb, k);
+ skip_bits(&alac->gb, k);
}
}
if (block_size > 0) {
memset(&output_buffer[output_count+1], 0, block_size * 4);
output_count += block_size;
-
}
if (block_size > 0xffff)
}
}
-#define SIGN_EXTENDED32(val, bits) ((val << (32 - bits)) >> (32 - bits))
+static inline int32_t extend_sign32(int32_t val, int bits)
+{
+ return (val << (32 - bits)) >> (32 - bits);
+}
-#define SIGN_ONLY(v) \
- ((v < 0) ? (-1) : \
- ((v > 0) ? (1) : \
- (0)))
+static inline int sign_only(int v)
+{
+ return v ? FFSIGN(v) : 0;
+}
static void predictor_decompress_fir_adapt(int32_t *error_buffer,
int32_t *buffer_out,
*buffer_out = *error_buffer;
if (!predictor_coef_num) {
- if (output_size <= 1) return;
+ if (output_size <= 1)
+ return;
+
memcpy(buffer_out+1, error_buffer+1, (output_size-1) * 4);
return;
}
/* second-best case scenario for fir decompression,
* error describes a small difference from the previous sample only
*/
- if (output_size <= 1) return;
+ if (output_size <= 1)
+ return;
for (i = 0; i < output_size - 1; i++) {
int32_t prev_value;
int32_t error_value;
prev_value = buffer_out[i];
error_value = error_buffer[i+1];
- buffer_out[i+1] = SIGN_EXTENDED32((prev_value + error_value), readsamplesize);
+ buffer_out[i+1] =
+ extend_sign32((prev_value + error_value), readsamplesize);
}
return;
}
/* read warm-up samples */
- if (predictor_coef_num > 0) {
- int i;
+ if (predictor_coef_num > 0)
for (i = 0; i < predictor_coef_num; i++) {
int32_t val;
val = buffer_out[i] + error_buffer[i+1];
-
- val = SIGN_EXTENDED32(val, readsamplesize);
-
+ val = extend_sign32(val, readsamplesize);
buffer_out[i+1] = val;
}
- }
#if 0
/* 4 and 8 are very common cases (the only ones i've seen). these
}
#endif
-
/* general case */
if (predictor_coef_num > 0) {
- for (i = predictor_coef_num + 1;
- i < output_size;
- i++) {
+ for (i = predictor_coef_num + 1; i < output_size; i++) {
int j;
int sum = 0;
int outval;
outval = (1 << (predictor_quantitization-1)) + sum;
outval = outval >> predictor_quantitization;
outval = outval + buffer_out[0] + error_val;
- outval = SIGN_EXTENDED32(outval, readsamplesize);
+ outval = extend_sign32(outval, readsamplesize);
buffer_out[predictor_coef_num+1] = outval;
while (predictor_num >= 0 && error_val > 0) {
int val = buffer_out[0] - buffer_out[predictor_coef_num - predictor_num];
- int sign = SIGN_ONLY(val);
+ int sign = sign_only(val);
predictor_coef_table[predictor_num] -= sign;
while (predictor_num >= 0 && error_val < 0) {
int val = buffer_out[0] - buffer_out[predictor_coef_num - predictor_num];
- int sign = - SIGN_ONLY(val);
+ int sign = - sign_only(val);
predictor_coef_table[predictor_num] -= sign;
}
}
-static void deinterlace_16(int32_t *buffer_a, int32_t *buffer_b,
- int16_t *buffer_out,
- int numchannels, int numsamples,
- uint8_t interlacing_shift,
- uint8_t interlacing_leftweight)
+static void reconstruct_stereo_16(int32_t *buffer[MAX_CHANNELS],
+ int16_t *buffer_out,
+ int numchannels, int numsamples,
+ uint8_t interlacing_shift,
+ uint8_t interlacing_leftweight)
{
int i;
- if (numsamples <= 0) return;
+ if (numsamples <= 0)
+ return;
/* weighted interlacing */
if (interlacing_leftweight) {
for (i = 0; i < numsamples; i++) {
- int32_t difference, midright;
- int16_t left;
- int16_t right;
+ int32_t a, b;
- midright = buffer_a[i];
- difference = buffer_b[i];
+ a = buffer[0][i];
+ b = buffer[1][i];
+ a -= (b * interlacing_leftweight) >> interlacing_shift;
+ b += a;
- right = midright - ((difference * interlacing_leftweight) >> interlacing_shift);
- left = (midright - ((difference * interlacing_leftweight) >> interlacing_shift))
- + difference;
-
- buffer_out[i*numchannels] = left;
- buffer_out[i*numchannels + 1] = right;
+ buffer_out[i*numchannels] = b;
+ buffer_out[i*numchannels + 1] = a;
}
return;
for (i = 0; i < numsamples; i++) {
int16_t left, right;
- left = buffer_a[i];
- right = buffer_b[i];
+ left = buffer[0][i];
+ right = buffer[1][i];
buffer_out[i*numchannels] = left;
buffer_out[i*numchannels + 1] = right;
init_get_bits(&alac->gb, inbuffer, input_buffer_size * 8);
channels = get_bits(&alac->gb, 3) + 1;
+ if (channels > MAX_CHANNELS) {
+ av_log(avctx, AV_LOG_ERROR, "channels > %d not supported\n",
+ MAX_CHANNELS);
+ return input_buffer_size;
+ }
- /* 2^result = something to do with output waiting.
- * perhaps matters if we read > 1 frame in a pass?
- */
- get_bits(&alac->gb, 4);
-
- get_bits(&alac->gb, 12); /* unknown, skip 12 bits */
+ /* 2^result = something to do with output waiting.
+ * perhaps matters if we read > 1 frame in a pass?
+ */
+ skip_bits(&alac->gb, 4);
- hassize = get_bits(&alac->gb, 1); /* the output sample size is stored soon */
+ skip_bits(&alac->gb, 12); /* unknown, skip 12 bits */
- wasted_bytes = get_bits(&alac->gb, 2); /* unknown ? */
+ /* the output sample size is stored soon */
+ hassize = get_bits1(&alac->gb);
- isnotcompressed = get_bits(&alac->gb, 1); /* whether the frame is compressed */
+ wasted_bytes = get_bits(&alac->gb, 2); /* unknown ? */
- if (hassize) {
- /* now read the number of samples,
- * as a 32bit integer */
- outputsamples = get_bits(&alac->gb, 32);
- } else
- outputsamples = alac->setinfo_max_samples_per_frame;
+ /* whether the frame is compressed */
+ isnotcompressed = get_bits1(&alac->gb);
- *outputsize = outputsamples * alac->bytespersample;
- readsamplesize = alac->setinfo_sample_size - (wasted_bytes * 8) + channels - 1;
+ if (hassize) {
+ /* now read the number of samples as a 32bit integer */
+ outputsamples = get_bits(&alac->gb, 32);
+ } else
+ outputsamples = alac->setinfo_max_samples_per_frame;
- if (!isnotcompressed) {
- /* so it is compressed */
- int16_t predictor_coef_table[channels][32];
- int predictor_coef_num[channels];
- int prediction_type[channels];
- int prediction_quantitization[channels];
- int ricemodifier[channels];
+ *outputsize = outputsamples * alac->bytespersample;
+ readsamplesize = alac->setinfo_sample_size - (wasted_bytes * 8) + channels - 1;
- int i, chan;
+ if (!isnotcompressed) {
+ /* so it is compressed */
+ int16_t predictor_coef_table[channels][32];
+ int predictor_coef_num[channels];
+ int prediction_type[channels];
+ int prediction_quantitization[channels];
+ int ricemodifier[channels];
+ int i, chan;
- interlacing_shift = get_bits(&alac->gb, 8);
- interlacing_leftweight = get_bits(&alac->gb, 8);
+ interlacing_shift = get_bits(&alac->gb, 8);
+ interlacing_leftweight = get_bits(&alac->gb, 8);
- for (chan = 0; chan < channels; chan++) {
+ for (chan = 0; chan < channels; chan++) {
prediction_type[chan] = get_bits(&alac->gb, 4);
prediction_quantitization[chan] = get_bits(&alac->gb, 4);
predictor_coef_num[chan] = get_bits(&alac->gb, 5);
/* read the predictor table */
- for (i = 0; i < predictor_coef_num[chan]; i++) {
+ for (i = 0; i < predictor_coef_num[chan]; i++)
predictor_coef_table[chan][i] = (int16_t)get_bits(&alac->gb, 16);
- }
- }
+ }
- if (wasted_bytes) {
- av_log(avctx, AV_LOG_ERROR, "FIXME: unimplemented, unhandling of wasted_bytes\n");
- }
+ if (wasted_bytes)
+ av_log(avctx, AV_LOG_ERROR, "FIXME: unimplemented, unhandling of wasted_bytes\n");
- for (chan = 0; chan < channels; chan++) {
+ for (chan = 0; chan < channels; chan++) {
bastardized_rice_decompress(alac,
alac->predicterror_buffer[chan],
outputsamples,
(1 << alac->setinfo_rice_kmodifier) - 1);
if (prediction_type[chan] == 0) {
- /* adaptive fir */
+ /* adaptive fir */
predictor_decompress_fir_adapt(alac->predicterror_buffer[chan],
alac->outputsamples_buffer[chan],
outputsamples,
prediction_quantitization[chan]);
} else {
av_log(avctx, AV_LOG_ERROR, "FIXME: unhandled prediction type: %i\n", prediction_type[chan]);
- /* i think the only other prediction type (or perhaps this is just a
- * boolean?) runs adaptive fir twice.. like:
+ /* I think the only other prediction type (or perhaps this is
+ * just a boolean?) runs adaptive fir twice.. like:
* predictor_decompress_fir_adapt(predictor_error, tempout, ...)
* predictor_decompress_fir_adapt(predictor_error, outputsamples ...)
* little strange..
*/
}
- }
- } else {
- /* not compressed, easy case */
- if (alac->setinfo_sample_size <= 16) {
- int i, chan;
- for (chan = 0; chan < channels; chan++) {
+ }
+ } else {
+ /* not compressed, easy case */
+ if (alac->setinfo_sample_size <= 16) {
+ int i, chan;
+ for (chan = 0; chan < channels; chan++)
for (i = 0; i < outputsamples; i++) {
int32_t audiobits;
audiobits = get_bits(&alac->gb, alac->setinfo_sample_size);
- audiobits = SIGN_EXTENDED32(audiobits, readsamplesize);
+ audiobits = extend_sign32(audiobits, readsamplesize);
alac->outputsamples_buffer[chan][i] = audiobits;
}
- }
- } else {
- int i, chan;
- for (chan = 0; chan < channels; chan++) {
+ } else {
+ int i, chan;
+ for (chan = 0; chan < channels; chan++)
for (i = 0; i < outputsamples; i++) {
int32_t audiobits;
alac->outputsamples_buffer[chan][i] = audiobits;
}
- }
- }
- /* wasted_bytes = 0; */
- interlacing_shift = 0;
- interlacing_leftweight = 0;
}
+ /* wasted_bytes = 0; */
+ interlacing_shift = 0;
+ interlacing_leftweight = 0;
+ }
- switch(alac->setinfo_sample_size) {
- case 16: {
- if (channels == 2) {
- deinterlace_16(alac->outputsamples_buffer[0],
- alac->outputsamples_buffer[1],
- (int16_t*)outbuffer,
- alac->numchannels,
- outputsamples,
- interlacing_shift,
- interlacing_leftweight);
- } else {
- int i;
- for (i = 0; i < outputsamples; i++) {
- int16_t sample = alac->outputsamples_buffer[0][i];
- ((int16_t*)outbuffer)[i * alac->numchannels] = sample;
- }
- }
- break;
- }
- case 20:
- case 24:
- case 32:
- av_log(avctx, AV_LOG_ERROR, "FIXME: unimplemented sample size %i\n", alac->setinfo_sample_size);
- break;
- default:
- break;
+ switch(alac->setinfo_sample_size) {
+ case 16:
+ if (channels == 2) {
+ reconstruct_stereo_16(alac->outputsamples_buffer,
+ (int16_t*)outbuffer,
+ alac->numchannels,
+ outputsamples,
+ interlacing_shift,
+ interlacing_leftweight);
+ } else {
+ int i;
+ for (i = 0; i < outputsamples; i++) {
+ int16_t sample = alac->outputsamples_buffer[0][i];
+ ((int16_t*)outbuffer)[i * alac->numchannels] = sample;
+ }
}
-
+ break;
+ case 20:
+ case 24:
+ // It is not clear if there exist any encoder that creates 24 bit ALAC
+ // files. iTunes convert 24 bit raw files to 16 bit before encoding.
+ case 32:
+ av_log(avctx, AV_LOG_ERROR, "FIXME: unimplemented sample size %i\n", alac->setinfo_sample_size);
+ break;
+ default:
+ break;
+ }
return input_buffer_size;
}
projects / ffmpeg / blobdiff