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FS-7772: mod_opus: add functionality to keep FEC enabled on the encoder by modifying the bitrate if packet loss changes (Opus codec specific behaviour).

This commit is contained in:
Dragos Oancea 2015-07-03 11:21:27 -04:00
parent 2f836a2c53
commit b3f453b02f
1 changed files with 57 additions and 1 deletions
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58
src/mod/codecs/mod_opus/mod_opus.c
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@ -25,6 +25,7 @@
*
* Brian K. West <brian@freeswitch.org>
* Noel Morgan <noel@vwci.com>
* Dragos Oancea <droancea@yahoo.com>
*
* mod_opus.c -- The OPUS ultra-low delay audio codec (http://www.opus-codec.org/)
*
@ -86,6 +87,7 @@ struct {
int sprop_maxcapturerate;
int plpct;
int asymmetric_samplerates;
int keep_fec;
int debuginfo;
switch_mutex_t *mutex;
} opus_prefs;
@ -594,6 +596,8 @@ static switch_status_t opus_load_config(switch_bool_t reload)
opus_prefs.plpct = atoi(val);
} else if (!strcasecmp(key, "asymmetric-sample-rates")) {
opus_prefs.asymmetric_samplerates = atoi(val);
} else if (!strcasecmp(key, "keep-fec-enabled")) {
opus_prefs.keep_fec = atoi(val);
} else if (!strcasecmp(key, "maxaveragebitrate")) {
opus_prefs.maxaveragebitrate = atoi(val);
if ( opus_prefs.maxaveragebitrate < 6000 || opus_prefs.maxaveragebitrate > 510000 ) {
@ -621,6 +625,55 @@ static switch_status_t opus_load_config(switch_bool_t reload)
return status;
}
static switch_status_t switch_opus_keep_fec_enabled(switch_codec_t *codec)
{
struct opus_context *context = codec->private_info;
opus_int32 current_bitrate;
opus_int32 current_loss;
uint32_t LBRR_threshold_bitrate,LBRR_rate_thres_bps,real_target_bitrate ;
opus_int32 a32,b32;
uint32_t fs = context->enc_frame_size * 1000 / (codec->implementation->microseconds_per_packet / 1000);
float frame_rate = 1000 / (codec->implementation->microseconds_per_packet / 1000);
uint32_t step = 8000 / (codec->implementation->microseconds_per_packet / 1000); /* this works for 10 ms, 20 ms and 40 ms frame sizes. not for 60 ms*/
opus_encoder_ctl(context->encoder_object, OPUS_GET_BITRATE(&current_bitrate));
opus_encoder_ctl(context->encoder_object, OPUS_GET_PACKET_LOSS_PERC(&current_loss));
if( fs == 8000 ) {
LBRR_rate_thres_bps = 12000; /*LBRR_NB_MIN_RATE_BPS*/
} else if( fs == 12000 ) {
LBRR_rate_thres_bps = 14000; /*LBRR_MB_MIN_RATE_BPS*/
} else {
LBRR_rate_thres_bps = 16000; /*LBRR_WB_MIN_RATE_BPS*/
}
/*see opus-1.1/src/opus_encoder.c , opus_encode_native() */
real_target_bitrate = 8 * (current_bitrate * context->enc_frame_size / ( fs * 8 ) - 1) * frame_rate ;
/*check if the internally used bitrate is above the threshold defined in opus-1.1/silk/control_codec.c */
a32 = LBRR_rate_thres_bps * (125 -(((current_loss) < (25)) ? (current_loss) : (25)));
b32 = ((opus_int32)((0.01) * ((opus_int64)1 << (16)) + 0.5));
LBRR_threshold_bitrate = (a32 >> 16) * (opus_int32)((opus_int16)b32) + (((a32 & 0x0000FFFF) * (opus_int32)((opus_int16)b32)) >> 16);
if ((!real_target_bitrate || !LBRR_threshold_bitrate)){
switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR,"Opus encoder: error while controlling FEC params\n");
return SWITCH_STATUS_FALSE;
}
/* Is there any FEC at the current bitrate and requested packet loss ?
* If yes, then keep the current bitrate. If not, modify bitrate to keep FEC on. */
if (real_target_bitrate > LBRR_threshold_bitrate) {
/*FEC is already enabled, do nothing*/
if (globals.debug)
switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG,"Opus encoder: FEC is enabled\n");
return SWITCH_STATUS_SUCCESS;
} else {
while (real_target_bitrate <= LBRR_threshold_bitrate) {
current_bitrate += step;
real_target_bitrate = 8 * (current_bitrate * context->enc_frame_size / ( fs * 8 ) - 1) * frame_rate ;
}
opus_encoder_ctl(context->encoder_object,OPUS_SET_BITRATE(current_bitrate));
if (globals.debug)
switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG,"Opus encoder: increased bitrate to [%d] to keep FEC enabled\n",current_bitrate);
return SWITCH_STATUS_SUCCESS;
}
}
static switch_status_t switch_opus_control(switch_codec_t *codec,
switch_codec_control_command_t cmd,
switch_codec_control_type_t ctype,
@ -645,6 +698,8 @@ static switch_status_t switch_opus_control(switch_codec_t *codec,
if (plpct != context->old_plpct) {
opus_encoder_ctl(context->encoder_object, OPUS_SET_PACKET_LOSS_PERC(plpct));
if (opus_prefs.keep_fec)
switch_opus_keep_fec_enabled(codec);
}
context->old_plpct = plpct;
}
@ -805,7 +860,7 @@ SWITCH_MODULE_LOAD_FUNCTION(mod_opus_load)
switch_opus_encode, /* function to encode raw data into encoded data */
switch_opus_decode, /* function to decode encoded data into raw data */
switch_opus_destroy); /* deinitalize a codec handle using this implementation */
codec_interface->implementations->codec_control = switch_opus_control;
settings.stereo = 1;
dft_fmtp = gen_fmtp(&settings, pool);
switch_core_codec_add_implementation(pool, codec_interface, SWITCH_CODEC_TYPE_AUDIO, /* enumeration defining the type of the codec */
@ -825,6 +880,7 @@ SWITCH_MODULE_LOAD_FUNCTION(mod_opus_load)
switch_opus_encode, /* function to encode raw data into encoded data */
switch_opus_decode, /* function to decode encoded data into raw data */
switch_opus_destroy); /* deinitalize a codec handle using this implementation */
codec_interface->implementations->codec_control = switch_opus_control;
bytes += 160;
samples += 480;