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adoptive the buffer size and buf count to reduce client latency #88

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4 changes: 4 additions & 0 deletions rx/rx_cmd.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -209,6 +209,10 @@ bool rx_common_cmd(int stream_type, conn_t* conn, char* cmd) {
ext_send_msg(conn->rx_channel, false, "MSG keepalive");
}

if (conn->type == STREAM_SOUND) {
send_msg(conn, false, "MSG keepalive");
}

// for STREAM_ADMIN and STREAM_MFG send a roundtrip keepalive so admin client can tell
// when server has gone away
if (conn->type == STREAM_ADMIN || conn->type == STREAM_MFG) {
Expand Down
1 change: 1 addition & 0 deletions rx/rx_sound.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -115,6 +115,7 @@ static str_hashes_t snd_cmd_hashes[] = {
{ "SET UAR ", CMD_UAR },
{ "SET AR O", CMD_AR_OKAY },
{ "SET unde", CMD_UNDERRUN },
{ "SET late", CMD_LATENCY },
{ "SET seq=", CMD_SEQ },
{ "SET lms_", CMD_LMS_AUTONOTCH },
{ "SET sam_", CMD_SAM_PLL },
Expand Down
1 change: 1 addition & 0 deletions rx/rx_sound.h
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Original file line number Diff line number Diff line change
Expand Up @@ -155,6 +155,7 @@ enum snd_cmd_key_e {
CMD_UAR,
CMD_AR_OKAY,
CMD_UNDERRUN,
CMD_LATENCY,
CMD_SEQ,
CMD_LMS_AUTONOTCH,
CMD_SAM_PLL,
Expand Down
20 changes: 20 additions & 0 deletions rx/rx_sound_cmd.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -596,6 +596,26 @@ void rx_sound_cmd(conn_t* conn, double frate, int n, char* cmd) {
}
break;

case CMD_LATENCY: {
int target, min, max, underruns, overruns, rtt, jitter;
int bufsize = 0, cb_ms = 0, cb_over = 0;
float avg;
u4_t seq;
n = sscanf(cmd, "SET latency target=%d min=%d max=%d avg=%f underruns=%d overruns=%d rtt=%d jitter=%d seq=%u bufsize=%d cb_ms=%d cb_over=%d",
&target, &min, &max, &avg, &underruns, &overruns, &rtt, &jitter, &seq, &bufsize, &cb_ms, &cb_over);
if (n == 12) {
did_cmd = true;
cprintf(conn, "SND: latency target=%d q=%d/%0.2f/%d und=%d ovr=%d rtt=%d jitter=%d seq=%u bufsize=%d cb_ms=%d cb_over=%d %s\n",
target, min, avg, max, underruns, overruns, rtt, jitter, seq, bufsize, cb_ms, cb_over, conn->ident_user);
} else if (n == 9) {
// backward compatibility with older clients
did_cmd = true;
cprintf(conn, "SND: latency target=%d q=%d/%0.2f/%d und=%d ovr=%d rtt=%d jitter=%d seq=%u %s\n",
target, min, avg, max, underruns, overruns, rtt, jitter, seq, conn->ident_user);
}
break;
}

#ifdef SND_SEQ_CHECK
case CMD_SEQ: {
int _seq, _sequence;
Expand Down
249 changes: 236 additions & 13 deletions web/openwebrx/audio.js
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Original file line number Diff line number Diff line change
Expand Up @@ -147,6 +147,30 @@ var audio_resample_ratio;
var audio_transition_bw;
var audio_min_nbuf;
var audio_max_nbuf;
var audio_adapt_min_nbuf;
var audio_adapt_max_nbuf;
var audio_adapt_target_nbuf;
var audio_adapt_last_underruns;
var audio_adapt_last_overruns;
var audio_adapt_stable_windows;
var audio_adapt_cooldown;
var audio_adapt_queue_avg;
var audio_adapt_queue_samples;
var audio_adapt_queue_min;
var audio_adapt_queue_max;
var audio_adapt_rtt_ewma;
var audio_adapt_jitter_ewma;
var audio_adapt_last_arrival_ms;
var audio_adapt_server_seq;

// size axis (two-axis adaptive controller)
var audio_adapt_cb_ewma_ms;
var audio_adapt_cb_overruns;
var audio_adapt_cb_overruns_last;
var audio_adapt_size_stable_windows;
var audio_adapt_size_cooldown;
var audio_adapt_size_min = 1024; // power-of-two; ScriptProcessor allows 256 but very risky
var audio_adapt_size_max = 8192; // ScriptProcessor max

// set in audio_connect()
var audio_stat_output_epoch;
Expand Down Expand Up @@ -225,6 +249,200 @@ function audio_camp(disconnect, is_local, less_buffering, compression)
audio_watchdog_restart = false;;
}

function audio_adapt_calc_nbuf(length_sec)
{
return Math.ceil((length_sec * audio_output_rate) / audio_buffer_size);
}

function audio_adapt_recalc_bounds()
{
audio_min_nbuf = audio_adapt_calc_nbuf(audio_buffer_min_length_sec);
audio_max_nbuf = audio_adapt_calc_nbuf(audio_buffer_max_length_sec);
audio_adapt_min_nbuf = audio_min_nbuf;
audio_adapt_max_nbuf = audio_max_nbuf;
audio_adapt_target_nbuf = audio_min_nbuf;
}

function audio_adapt_reset()
{
audio_adapt_last_underruns = audio_underrun_errors;
audio_adapt_last_overruns = audio_overrun_errors;
audio_adapt_stable_windows = 0;
audio_adapt_cooldown = 0;
audio_adapt_queue_avg = 0;
audio_adapt_queue_samples = 0;
audio_adapt_queue_min = 0;
audio_adapt_queue_max = 0;
audio_adapt_rtt_ewma = 0;
audio_adapt_jitter_ewma = 0;
audio_adapt_last_arrival_ms = 0;
audio_adapt_server_seq = 0;
audio_adapt_cb_ewma_ms = 0;
audio_adapt_cb_overruns = 0;
audio_adapt_cb_overruns_last = 0;
audio_adapt_size_stable_windows = 0;
audio_adapt_size_cooldown = 0;
}

function audio_adapt_note_arrival(seq)
{
var now = Date.now();
if (audio_adapt_last_arrival_ms) {
var delta = now - audio_adapt_last_arrival_ms;
if (audio_adapt_rtt_ewma == 0) {
audio_adapt_jitter_ewma = 0;
} else {
var err = Math.abs(delta - audio_adapt_rtt_ewma);
audio_adapt_jitter_ewma = audio_adapt_jitter_ewma? ((audio_adapt_jitter_ewma * 0.85) + (err * 0.15)) : err;
}
}
audio_adapt_last_arrival_ms = now;
audio_adapt_server_seq = seq;
}

function audio_adapt_set_rtt(rtt_ms)
{
if (!(rtt_ms > 0)) return;
audio_adapt_rtt_ewma = audio_adapt_rtt_ewma? ((audio_adapt_rtt_ewma * 0.8) + (rtt_ms * 0.2)) : rtt_ms;
}

function audio_adapt_update()
{
if (!audio_output_rate || !audio_buffer_size) return;

var qlen = audio_prepared_buffers.length;
audio_adapt_queue_samples++;
audio_adapt_queue_avg += qlen;
if (audio_adapt_queue_samples == 1) {
audio_adapt_queue_min = qlen;
audio_adapt_queue_max = qlen;
} else {
audio_adapt_queue_min = Math.min(audio_adapt_queue_min, qlen);
audio_adapt_queue_max = Math.max(audio_adapt_queue_max, qlen);
}

var underrun_delta = audio_underrun_errors - audio_adapt_last_underruns;
var overrun_delta = audio_overrun_errors - audio_adapt_last_overruns;
var queue_avg = audio_adapt_queue_samples? (audio_adapt_queue_avg / audio_adapt_queue_samples) : qlen;
var target = audio_adapt_target_nbuf;
var grew = false;

if (audio_buffering || underrun_delta > 0) {
target = Math.min(audio_adapt_max_nbuf, target + 1);
audio_adapt_stable_windows = 0;
audio_adapt_cooldown = 3;
grew = true;
} else if (overrun_delta > 0 || audio_adapt_queue_max > (target + 1)) {
target = Math.min(audio_adapt_max_nbuf, target + 1);
audio_adapt_stable_windows = 0;
audio_adapt_cooldown = Math.max(audio_adapt_cooldown, 2);
grew = true;
} else {
audio_adapt_stable_windows++;
if (audio_adapt_cooldown > 0) {
audio_adapt_cooldown--;
} else {
var advisory = audio_adapt_min_nbuf;
if (audio_adapt_rtt_ewma > 250) advisory++;
if (audio_adapt_jitter_ewma > 40) advisory++;
advisory = Math.min(audio_adapt_max_nbuf, advisory);
target = Math.max(target, advisory);
if (audio_adapt_stable_windows >= 6 && queue_avg > audio_adapt_min_nbuf && qlen > target && target > advisory) {
target--;
audio_adapt_stable_windows = 0;
}
}
}

audio_adapt_target_nbuf = Math.max(audio_adapt_min_nbuf, Math.min(audio_adapt_max_nbuf, target));
audio_min_nbuf = audio_adapt_target_nbuf;
audio_max_nbuf = Math.max(audio_min_nbuf + 2, Math.min(audio_adapt_max_nbuf, audio_adapt_target_nbuf + 6));
audio_adapt_last_underruns = audio_underrun_errors;
audio_adapt_last_overruns = audio_overrun_errors;

if (!grew && audio_prepared_buffers.length > audio_max_nbuf) {
audio.trim_bufs = true;
}

if ((audio_stat_input_epoch != -1) && ws_snd && ws_snd.up) {
snd_send('SET latency target='+ audio_adapt_target_nbuf +' min='+ audio_adapt_queue_min +' max='+ audio_adapt_queue_max +
' avg='+ queue_avg.toFixed(2) +' underruns='+ audio_underrun_errors +' overruns='+ audio_overrun_errors +
' rtt='+ Math.round(audio_adapt_rtt_ewma) +' jitter='+ Math.round(audio_adapt_jitter_ewma) +' seq='+ audio_adapt_server_seq +
' bufsize='+ audio_buffer_size +' cb_ms='+ Math.round(audio_adapt_cb_ewma_ms) +' cb_over='+ audio_adapt_cb_overruns);
}

audio_adapt_queue_avg = 0;
audio_adapt_queue_samples = 0;
audio_adapt_queue_min = 0;
audio_adapt_queue_max = 0;

audio_adapt_size_update();
}

function audio_adapt_note_callback(dur_ms)
{
if (!audio_buffer_size || !audio_output_rate) return;
var buf_ms = (audio_buffer_size / audio_output_rate) * 1000;
audio_adapt_cb_ewma_ms = audio_adapt_cb_ewma_ms? ((audio_adapt_cb_ewma_ms * 0.9) + (dur_ms * 0.1)) : dur_ms;
if (dur_ms > buf_ms * 0.7) audio_adapt_cb_overruns++;
}

function audio_adapt_size_update()
{
if (!audio_running || !audio_buffer_size || !audio_output_rate) return;
if (!audio_started) return;

var buf_ms = (audio_buffer_size / audio_output_rate) * 1000;
var cb_over_delta = audio_adapt_cb_overruns - audio_adapt_cb_overruns_last;
audio_adapt_cb_overruns_last = audio_adapt_cb_overruns;
// count axis just stored last_underruns; use stable_windows as the "count axis healthy" proxy
var count_healthy = (audio_adapt_stable_windows > 0);

var next_size = audio_buffer_size;

// FAST: grow on CPU stress
if (cb_over_delta > 0 || audio_adapt_cb_ewma_ms > buf_ms * 0.7) {
if (audio_buffer_size < audio_adapt_size_max) {
next_size = Math.min(audio_adapt_size_max, audio_buffer_size * 2);
}
audio_adapt_size_stable_windows = 0;
audio_adapt_size_cooldown = 10;
}
// SLOW: shrink only with sustained headroom and a healthy count axis
else if (audio_adapt_size_cooldown == 0 &&
audio_adapt_cb_ewma_ms > 0 && audio_adapt_cb_ewma_ms < buf_ms * 0.25 &&
count_healthy &&
audio_buffer_size > audio_adapt_size_min &&
audio_adapt_size_stable_windows >= 30) {
next_size = audio_buffer_size / 2;
audio_adapt_size_stable_windows = 0;
audio_adapt_size_cooldown = 5;
} else {
audio_adapt_size_stable_windows++;
if (audio_adapt_size_cooldown > 0) audio_adapt_size_cooldown--;
}

if (next_size != audio_buffer_size) {
console.log('AUDIO size axis: '+ audio_buffer_size +' -> '+ next_size +
' cb_ms='+ audio_adapt_cb_ewma_ms.toFixed(1) +' buf_ms='+ buf_ms.toFixed(1));
audio.buffer_size = next_size;
audio_buffer_size = next_size;
// reallocate buffers sized off audio_buffer_size; queue is reset by audio_connect(reconnect=1)
audio_data = new Int16Array(audio_buffer_size);
audio_data_unsquelched = new Int16Array(audio_buffer_size);
audio_last_output_buffer = new Float32Array(audio_buffer_size);
audio_last_output_buffer2 = new Float32Array(audio_buffer_size);
audio_silence_buffer = new Float32Array(audio_buffer_size);
// count-axis bounds are in buffers; recompute and let the count axis re-stabilize
audio_adapt_recalc_bounds();
audio_adapt_stable_windows = 0;
audio_adapt_cooldown = 3;
audio_buffering = true;
audio_adapt_cb_ewma_ms = 0; // EWMA must reset because buf_ms changed
audio_connect(1); // reinstantiates ScriptProcessorNode at the new size
}
}

function audio_reset()
{
audio.trim_bufs = true;
Expand Down Expand Up @@ -293,7 +511,8 @@ function audio_init(is_local, less_buffering, compression)
audio_change_sq_UI_latch = false;
audio_last_sq = undefined; // so set true/false first time
audio_firefox_watchdog = 0;

audio_adapt_reset();

kiwi_clearInterval(audio_stats_interval);
if (audio_init_disconnect) {
if (audio.d) console.log('AUDIO audio_init DISCONNECT');
Expand All @@ -309,12 +528,12 @@ function audio_init(is_local, less_buffering, compression)
if (a != null) {
var a2 = a.split(',');
abuf = parseFloat(a2[0]);
if (!isNaN(abuf) && abuf >= 0.15 && abuf <= 5.0) {
if (!isNaN(abuf) && abuf >= 0.08 && abuf <= 5.0) {
console.log('AUDIO override abuf='+ a);
var max = abuf * 3;
if (a2.length >= 2) {
var m = parseFloat(a2[1]);
if (!isNaN(m) && m >= 0.15 && m <= 5.0 && m > abuf) {
if (!isNaN(m) && m >= 0.08 && m <= 5.0 && m > abuf) {
max = m;
}
} else {
Expand Down Expand Up @@ -346,21 +565,21 @@ function audio_init(is_local, less_buffering, compression)

if (buffering_scheme == 2) {
audio_buffer_size = audio.buffer_size;
audio_buffer_min_length_sec = 0.25; // min_nbuf = 2 @ 44.1 kHz
audio_buffer_min_length_sec = 0.15; // min_nbuf = 1 @ 44.1 kHz; controller raises if needed
audio_buffer_max_length_sec = 2.00;
scheme_s = 'less buf, local';
} else

if (buffering_scheme == 1) {
audio_buffer_size = audio.buffer_size;
audio_buffer_min_length_sec = 0.35; // min_nbuf = 4 @ 44.1 kHz
audio_buffer_min_length_sec = 0.20; // min_nbuf = 2 @ 44.1 kHz; controller raises if needed
audio_buffer_max_length_sec = 3.00;
scheme_s = 'less buf, remote';
} else

if (buffering_scheme == 0) {
audio_buffer_size = audio.buffer_size;
audio_buffer_min_length_sec = 0.85; // min_nbuf = 5 @ 44.1 kHz
audio_buffer_min_length_sec = 0.50; // min_nbuf = 3 @ 44.1 kHz; controller raises if needed
audio_buffer_max_length_sec = 3.40;
scheme_s = 'more buf';
}
Expand Down Expand Up @@ -459,8 +678,7 @@ function audio_rate(input_rate)
audio_resample_ratio = 1;
}

audio_min_nbuf = Math.ceil((audio_buffer_min_length_sec * audio_output_rate) / audio_buffer_size);
audio_max_nbuf = Math.ceil((audio_buffer_max_length_sec * audio_output_rate) / audio_buffer_size);
audio_adapt_recalc_bounds();
console.log('AUDIO audio_input_rate='+ audio_input_rate +' audio_output_rate='+ audio_output_rate);
console.log('AUDIO min_length_sec='+ audio_buffer_min_length_sec +'('+ audio_min_nbuf +' bufs) max_length_sec='+ audio_buffer_max_length_sec +'('+ audio_max_nbuf +' bufs)');
}
Expand Down Expand Up @@ -617,10 +835,11 @@ function audio_watchdog_process(ev)
// NB: always use kiwi_log() instead of console.log() in here
function audio_onprocess(ev)
{
var _cb_t0 = (typeof performance !== 'undefined' && performance.now)? performance.now() : Date.now();
audio_firefox_watchdog++;

if (audio_disconnected) return;

//if (!audio_started) { kiwi_log('audio_onprocess audio_started='+ audio_started +' ql='+ audio_prepared_buffers.length +' ----------------'); }
if (audio_stat_output_epoch == -1) {
audio_stat_output_epoch = (new Date()).getTime();
Expand Down Expand Up @@ -655,6 +874,7 @@ function audio_onprocess(ev)
audio_need_stats_reset = true;
ev.outputBuffer.copyToChannel(audio_silence_buffer, 0);
if (audio_channels == 2) ev.outputBuffer.copyToChannel(audio_silence_buffer, 1);
audio_adapt_note_callback((((typeof performance !== 'undefined' && performance.now)? performance.now() : Date.now()) - _cb_t0));
return;
}

Expand Down Expand Up @@ -694,6 +914,7 @@ function audio_onprocess(ev)
kiwi_log('AUDIO dly='+ audio_meas_dly);
audio_meas_dly_start = 0;
}
audio_adapt_note_callback((((typeof performance !== 'undefined' && performance.now)? performance.now() : Date.now()) - _cb_t0));
}

//setInterval(function() { audio_ext_adc_ovfl = audio_ext_adc_ovfl? false:true; }, 1000);
Expand Down Expand Up @@ -732,9 +953,10 @@ function audio_periodic()
//if (audio_watchdog_restart) { console.log('audio_watchdog_restart '+ audio_watchdog_restart_cnt); audio_watchdog_restart_cnt++; }

//console.log('AUDIO FLUSH');
audio_adapt_update();
var overran = false;
//var audio_buffer_mid_length_sec = audio_buffer_min_length_sec + ((audio_buffer_max_length_sec - audio_buffer_min_length_sec) /2);

while (audio_prepared_buffers.length > audio_max_nbuf) {
overran = true;
audio_prepared_buffers.shift();
Expand Down Expand Up @@ -825,7 +1047,8 @@ function audio_recv(data, ws, firstChars)
//if (flags != audio.last_flags) { console.log('AUDIO flags='+ flags.toHex(+4)); audio.last_flags = flags; }

var seq = (h8[7] << 24) | (h8[6] << 16) | (h8[5] << 8) | h8[4];

audio_adapt_note_arrival(seq);

// if camping and compressed have to wait for MSG with adpcm state
//if (audio_camping)
//console.log('camping='+ audio_camping +' comp='+ ((flags & audio.SND_FLAG_COMPRESSED)? 1:0) +' seq='+ seq);
Expand Down
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