int decode_chunk( ape_ctx_t* ape_ctx,
unsigned char* inbuffer, int* firstbyte,
int* bytesconsumed,
int32_t* decoded0, int32_t* decoded1,
int count)
{
int res;
int32_t left, right;
#define SCALE(x) (x)
if ((ape_ctx->channels==1) || (ape_ctx->frameflags & APE_FRAMECODE_PSEUDO_STEREO)) {
if (ape_ctx->frameflags & APE_FRAMECODE_STEREO_SILENCE) {
res = entropy_decode(ape_ctx, inbuffer, firstbyte, bytesconsumed, decoded0, decoded1, count);
/* We are pure silence, so we're done. */
return 0;
} else {
res = entropy_decode(ape_ctx, inbuffer, firstbyte, bytesconsumed, decoded0, NULL, count);
}
switch (ape_ctx->compressiontype)
{
case 2000:
apply_filter_16_11(ape_ctx->fileversion,decoded0,NULL,count);
break;
case 3000:
apply_filter_64_11(ape_ctx->fileversion,decoded0,NULL,count);
break;
case 4000:
apply_filter_32_10(ape_ctx->fileversion,decoded0,NULL,count);
apply_filter_256_13(ape_ctx->fileversion,decoded0,NULL,count);
break;
case 5000:
apply_filter_16_11(ape_ctx->fileversion,decoded0,NULL,count);
apply_filter_256_13(ape_ctx->fileversion,decoded0,NULL,count);
apply_filter_1280_15(ape_ctx->fileversion,decoded0,NULL,count);
}
/* Now apply the predictor decoding */
predictor_decode_mono(ape_ctx,decoded0,count);
if (ape_ctx->channels==2) {
/* Pseudo-stereo - just copy left channel to right channel */
while (count--)
{
left = *decoded0;
*(decoded1++) = *(decoded0++) = SCALE(left);
}
} else {
/* Mono - do nothing unless it's 8-bit audio */
if (ape_ctx->bps == 8) {
/* TODO: Handle 8-bit streams */
}
}
} else { /* Stereo */
if (ape_ctx->frameflags & APE_FRAMECODE_STEREO_SILENCE) {
/* We are pure silence, so we're done. */
return 0;
}
res = entropy_decode(ape_ctx, inbuffer, firstbyte, bytesconsumed, decoded0, decoded1, count);
/* Apply filters - compression type 1000 doesn't have any */
switch (ape_ctx->compressiontype)
{
case 2000:
apply_filter_16_11(ape_ctx->fileversion,decoded0,decoded1,count);
break;
case 3000:
apply_filter_64_11(ape_ctx->fileversion,decoded0,decoded1,count);
break;
case 4000:
apply_filter_32_10(ape_ctx->fileversion,decoded0,decoded1,count);
apply_filter_256_13(ape_ctx->fileversion,decoded0,decoded1,count);
break;
case 5000:
apply_filter_16_11(ape_ctx->fileversion,decoded0,decoded1,count);
apply_filter_256_13(ape_ctx->fileversion,decoded0,decoded1,count);
apply_filter_1280_15(ape_ctx->fileversion,decoded0,decoded1,count);
}
/* Now apply the predictor decoding */
predictor_decode_stereo(ape_ctx,decoded0,decoded1,count);
if (ape_ctx->bps == 8) {
/* TODO: Handle 8-bit streams */
} else {
/* Decorrelate and scale to output depth */
while (count--)
{
left = *decoded1 - (*decoded0 / 2);
right = left + *decoded0;
*(decoded0++) = SCALE(left);
*(decoded1++) = SCALE(right);
}
}
}
return res;
}
int ICODE_ATTR_DEMAC decode_chunk(struct ape_ctx_t* ape_ctx,
unsigned char* inbuffer, int* firstbyte,
int* bytesconsumed,
int32_t* decoded0, int32_t* decoded1,
int count)
{
int32_t left, right;
#ifdef ROCKBOX
int scale = (APE_OUTPUT_DEPTH - ape_ctx->bps);
#define SCALE(x) ((x) << scale)
#else
#define SCALE(x) (x)
#endif
if ((ape_ctx->channels==1) || ((ape_ctx->frameflags
& (APE_FRAMECODE_PSEUDO_STEREO|APE_FRAMECODE_STEREO_SILENCE))
== APE_FRAMECODE_PSEUDO_STEREO)) {
entropy_decode(ape_ctx, inbuffer, firstbyte, bytesconsumed,
decoded0, NULL, count);
if (ape_ctx->frameflags & APE_FRAMECODE_MONO_SILENCE) {
/* We are pure silence, so we're done. */
return 0;
}
switch (ape_ctx->compressiontype)
{
case 2000:
apply_filter_16_11(ape_ctx->fileversion,decoded0,NULL,count);
break;
case 3000:
apply_filter_64_11(ape_ctx->fileversion,decoded0,NULL,count);
break;
case 4000:
apply_filter_32_10(ape_ctx->fileversion,decoded0,NULL,count);
apply_filter_256_13(ape_ctx->fileversion,decoded0,NULL,count);
break;
case 5000:
apply_filter_16_11(ape_ctx->fileversion,decoded0,NULL,count);
apply_filter_256_13(ape_ctx->fileversion,decoded0,NULL,count);
apply_filter_1280_15(ape_ctx->fileversion,decoded0,NULL,count);
}
/* Now apply the predictor decoding */
predictor_decode_mono(&ape_ctx->predictor,decoded0,count);
if (ape_ctx->channels==2) {
/* Pseudo-stereo - copy left channel to right channel */
while (count--)
{
left = *decoded0;
*(decoded1++) = *(decoded0++) = SCALE(left);
}
}
#ifdef ROCKBOX
else {
/* Scale to output depth */
while (count--)
{
left = *decoded0;
*(decoded0++) = SCALE(left);
}
}
#endif
} else { /* Stereo */
entropy_decode(ape_ctx, inbuffer, firstbyte, bytesconsumed,
decoded0, decoded1, count);
if ((ape_ctx->frameflags & APE_FRAMECODE_STEREO_SILENCE)
== APE_FRAMECODE_STEREO_SILENCE) {
/* We are pure silence, so we're done. */
return 0;
}
/* Apply filters - compression type 1000 doesn't have any */
switch (ape_ctx->compressiontype)
{
case 2000:
apply_filter_16_11(ape_ctx->fileversion,decoded0,decoded1,count);
break;
case 3000:
apply_filter_64_11(ape_ctx->fileversion,decoded0,decoded1,count);
break;
case 4000:
apply_filter_32_10(ape_ctx->fileversion,decoded0,decoded1,count);
apply_filter_256_13(ape_ctx->fileversion,decoded0,decoded1,count);
break;
case 5000:
apply_filter_16_11(ape_ctx->fileversion,decoded0,decoded1,count);
apply_filter_256_13(ape_ctx->fileversion,decoded0,decoded1,count);
apply_filter_1280_15(ape_ctx->fileversion,decoded0,decoded1,count);
}
/* Now apply the predictor decoding */
predictor_decode_stereo(&ape_ctx->predictor,decoded0,decoded1,count);
/* Decorrelate and scale to output depth */
while (count--)
{
left = *decoded1 - (*decoded0 / 2);
right = left + *decoded0;
*(decoded0++) = SCALE(left);
*(decoded1++) = SCALE(right);
}
}
return 0;
}
