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some small speed further optimization to 24 bits SPDIF
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@philippe44
philippe44 committed Sep 23, 2023
1 parent 456f16f commit b413780
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Showing 2 changed files with 22 additions and 32 deletions.
2 changes: 1 addition & 1 deletion components/services/monitor.c
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Original file line number Diff line number Diff line change
Expand Up @@ -26,7 +26,7 @@
#include "cJSON.h"
#include "tools.h"

#define PSEUDO_IDLE_STACK_SIZE (6*1024)
#define PSEUDO_IDLE_STACK_SIZE (8*1024)

#define MONITOR_TIMER (10*1000)
#define SCRATCH_SIZE 256
Expand Down
52 changes: 21 additions & 31 deletions components/squeezelite/output_i2s.c
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Original file line number Diff line number Diff line change
Expand Up @@ -93,9 +93,6 @@ static void (*pseudo_idle_chain)(uint32_t now);
#define CONFIG_AMP_GPIO_LEVEL 1
#endif

#define VUCP24 (0xCC)
#define VUCP24I (0x32)

extern struct outputstate output;
extern struct buffer *streambuf;
extern struct buffer *outputbuf;
Expand All @@ -117,8 +114,6 @@ static frames_t oframes;
static struct {
bool enabled;
u8_t *buf;
size_t count;
u8_t vucp;
} spdif;
static size_t dma_buf_frames;
static TaskHandle_t output_i2s_task;
Expand All @@ -134,7 +129,7 @@ static int _i2s_write_frames(frames_t out_frames, bool silence, s32_t gainL, s32
static void output_thread_i2s(void *arg);
static void i2s_stats(uint32_t now);

static void spdif_convert(ISAMPLE_T *src, size_t frames, u32_t *dst, size_t *count, u8_t *vucp);
static void spdif_convert(ISAMPLE_T *src, size_t frames, u32_t *dst);
static void (*jack_handler_chain)(bool inserted);

#define I2C_PORT 0
Expand Down Expand Up @@ -545,8 +540,6 @@ static void output_thread_i2s(void *arg) {
isI2SStarted = false;
i2s_stop(CONFIG_I2S_NUM);
adac->power(ADAC_STANDBY);
spdif.count = 0;
spdif.vucp = VUCP24;
}
usleep(100000);
continue;
Expand Down Expand Up @@ -593,6 +586,7 @@ static void output_thread_i2s(void *arg) {
i2s_zero_dma_buffer(CONFIG_I2S_NUM);
i2s_start(CONFIG_I2S_NUM);
adac->power(ADAC_ON);
if (spdif.enabled) spdif_convert(NULL, 0, NULL);
}

// this does not work well as set_sample_rates resets the fifos (and it's too early)
Expand Down Expand Up @@ -622,7 +616,7 @@ static void output_thread_i2s(void *arg) {
// need IRAM for speed but can't allocate a FRAME_BLOCK * 16, so process by smaller chunks
while (count < oframes) {
size_t chunk = min(SPDIF_BLOCK, oframes - count);
spdif_convert((ISAMPLE_T*) obuf + count * 2, chunk, (u32_t*) spdif.buf, &spdif.count, &spdif.vucp);
spdif_convert((ISAMPLE_T*) obuf + count * 2, chunk, (u32_t*) spdif.buf);
i2s_write(CONFIG_I2S_NUM, spdif.buf, chunk * 16, &obytes, portMAX_DELAY);
bytes += obytes / (16 / BYTES_PER_FRAME);
count += chunk;
Expand Down Expand Up @@ -663,7 +657,7 @@ static void i2s_stats(uint32_t now) {
// then see if we need to act
if (output.state <= OUTPUT_STOPPED || now < last + STATS_PERIOD_MS) return;
last = now;

LOG_INFO( "Output State: %d, current sample rate: %d, bytes per frame: %d", output.state, output.current_sample_rate, BYTES_PER_FRAME);
LOG_INFO( LINE_MIN_MAX_FORMAT_HEAD1);
LOG_INFO( LINE_MIN_MAX_FORMAT_HEAD2);
Expand All @@ -687,11 +681,12 @@ static void i2s_stats(uint32_t now) {
/****************************************************************************************
* SPDIF support
*/

#define PREAMBLE_B (0xE8) //11101000
#define PREAMBLE_M (0xE2) //11100010
#define PREAMBLE_W (0xE4) //11100100

static const u8_t VUCP24[2] = { 0xCC, 0x32 };

static const u16_t spdif_bmclookup[256] = {
0xcccc, 0xb333, 0xd333, 0xaccc, 0xcb33, 0xb4cc, 0xd4cc, 0xab33,
0xcd33, 0xb2cc, 0xd2cc, 0xad33, 0xcacc, 0xb533, 0xd533, 0xaacc,
Expand Down Expand Up @@ -740,24 +735,28 @@ static const u16_t spdif_bmclookup[256] = {
The I2S interface must output first the B/M/W preamble which means that second
32 bits words must be first and so must be marked right channel.
*/
static void IRAM_ATTR spdif_convert(ISAMPLE_T *src, size_t frames, u32_t *dst, size_t *count, u8_t *vucp) {
static void IRAM_ATTR spdif_convert(ISAMPLE_T *src, size_t frames, u32_t *dst) {
static u8_t vu, count;
register u16_t hi, lo;
#if BYTES_PER_FRAME == 8
register u16_t aux;
#endif
register u8_t vu = *vucp;
size_t cnt = *count;


if (!src) {
count = 192;
vu = VUCP24[0];
}

while (frames--) {
// start with left channel
#if BYTES_PER_FRAME == 4
hi = spdif_bmclookup[(u8_t)(*src >> 8)];
lo = spdif_bmclookup[(u8_t)*src++];
if (lo & 1) hi = ~hi;

if (++cnt > 191) {
if (!count--) {
*dst++ = (vu << 24) | (PREAMBLE_B << 16) | 0xCCCC;
cnt = 0;
count = 192;
} else {
*dst++ = (vu << 24) | (PREAMBLE_M << 16) | 0xCCCC;
}
Expand All @@ -768,16 +767,16 @@ static void IRAM_ATTR spdif_convert(ISAMPLE_T *src, size_t frames, u32_t *dst, s
if (aux & 1) lo = ~lo;
if (lo & 1) hi = ~hi;

if (++cnt > 191) {

if (!count--) {
*dst++ = (vu << 24) | (PREAMBLE_B << 16) | aux;
cnt = 0;
count = 192;
} else {
*dst++ = (vu << 24) | (PREAMBLE_M << 16) | aux;
}
#endif

if (hi & 1) vu = VUCP24I;
else vu = VUCP24;
vu = VUCP24[hi & 1];
*dst++ = ((u32_t)lo << 16) | hi;

// then do right channel, no need to check PREAMBLE_B
Expand All @@ -797,16 +796,7 @@ static void IRAM_ATTR spdif_convert(ISAMPLE_T *src, size_t frames, u32_t *dst, s
*dst++ = (vu << 24) | (PREAMBLE_W << 16) | aux;
#endif

if (hi & 1) vu = VUCP24I;
else vu = VUCP24;
vu = VUCP24[hi & 1];
*dst++ = ((u32_t)lo << 16) | hi;
}

*count = cnt;
*vucp = vu;
}





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