FS-8080: mod_opus: fine-tune FEC with repacketization (ptimes: 80 ms,100 ms,120 ms)

diff --git a/src/mod/codecs/mod_opus/mod_opus.c b/src/mod/codecs/mod_opus/mod_opus.c
index c50418aa87c27b7c69b8b7e3cbb50803959070b0..13c47057efa08e9b568a5234d134fb8093ba01f6 100644 (file)
--- a/src/mod/codecs/mod_opus/mod_opus.c
+++ b/src/mod/codecs/mod_opus/mod_opus.c
@@ -658,7 +658,7 @@ static switch_status_t switch_opus_encode_repacketize(switch_codec_t *codec,
        /* work inside the available buffer to avoid other buffer allocations. *encoded_data_len will be SWITCH_RECOMMENDED_BUFFER_SIZE */
        unsigned char *enc_ptr_buf =  (unsigned char *)encoded_data + (len / 2);
        int nb_frames = codec->implementation->microseconds_per_packet / 20000 ; /* requested ptime: 20 ms * nb_frames */
-       int i, bytes = 0;
+       int frame_size, i, bytes = 0, want_fec = 0, toggle_fec = 0;
        opus_int32 ret = 0;
        opus_int32 total_len = 0;
        switch_status_t status = SWITCH_STATUS_SUCCESS;
@@ -666,11 +666,30 @@ static switch_status_t switch_opus_encode_repacketize(switch_codec_t *codec,
        if (!context) {
                switch_goto_status(SWITCH_STATUS_FALSE, end);
        }
-
+       opus_encoder_ctl(context->encoder_object, OPUS_GET_INBAND_FEC(&want_fec));
+       if (want_fec && context->codec_settings.useinbandfec) {
+               /* if FEC might be used , pack only 2 frames like: 80 ms = 2 x 40 ms , 120 ms = 2 x 60 ms  */
+               /* the first frame in the resulting payload must have FEC, the other must not ( avoid redundant FEC payload ) */
+               nb_frames = 2;
+               if (codec->implementation->microseconds_per_packet / 1000 == 100) { /* 100 ms = 20 ms * 5 . because there is no 50 ms frame in Opus */
+                               nb_frames = 5;
+               }
+               toggle_fec = 1;
+       }
+       frame_size = (decoded_data_len / 2) / nb_frames;
+       if((frame_size * nb_frames) != context->enc_frame_size) {
+               switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR,"Encoder Error: Decoded Datalen %u Number of frames: %d Encoder frame size: %d\n",decoded_data_len,nb_frames,context->enc_frame_size);
+               switch_goto_status(SWITCH_STATUS_GENERR, end);
+       }
        opus_repacketizer_init(rp);
+       dec_ptr_buf = (int16_t *)decoded_data;
        for (i = 0; i < nb_frames; i++) {
-               dec_ptr_buf = (int16_t *)decoded_data + i * (decoded_data_len / 2 / nb_frames);
-               bytes = opus_encode(context->encoder_object, (opus_int16 *) dec_ptr_buf, context->enc_frame_size / nb_frames, enc_ptr_buf, len);
+               bytes = opus_encode(context->encoder_object, (opus_int16 *) dec_ptr_buf, frame_size, enc_ptr_buf, len);
+                /* set inband FEC off for the next frame to be packed, the current frame may contain FEC */
+               if (toggle_fec == 1) {
+                       toggle_fec = 0;
+                       opus_encoder_ctl(context->encoder_object, OPUS_SET_INBAND_FEC(toggle_fec));
+               } 
                if (bytes < 0) {
                        switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Encoder Error: %s Decoded Datalen %u Codec NumberChans %u" \
                                                          "Len %u DecodedDate %p EncodedData %p ContextEncoderObject %p enc_frame_size: %d\n",
@@ -678,23 +697,21 @@ static switch_status_t switch_opus_encode_repacketize(switch_codec_t *codec,
                                                          (void *) decoded_data, (void *) encoded_data, (void *) context->encoder_object, context->enc_frame_size);
                        switch_goto_status(SWITCH_STATUS_GENERR, end);
                }
-
                /* enc_ptr_buf : Opus API manual:  "The application must ensure this pointer remains valid until the next call to opus_repacketizer_init() or opus_repacketizer_destroy()." */
                ret = opus_repacketizer_cat(rp, enc_ptr_buf, bytes);
                if (ret != OPUS_OK) {
                        switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Opus encoder: error while repacketizing (cat) : %s !\n",opus_strerror(ret));
                        switch_goto_status(SWITCH_STATUS_GENERR, end);
                }
-
                enc_ptr_buf += bytes;
                total_len += bytes;
+               dec_ptr_buf += frame_size ;
        }
        /* this will never happen, unless there is a huge and unsupported number of frames */
        if (total_len + opus_repacketizer_get_nb_frames(rp) > len / 2) {
                switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Opus encoder: error while repacketizing: not enough buffer space\n");
                switch_goto_status(SWITCH_STATUS_GENERR, end);
        }
-
        ret = opus_repacketizer_out(rp, encoded_data, total_len+opus_repacketizer_get_nb_frames(rp));
 
        if (globals.debug || context->debug) {
@@ -703,10 +720,12 @@ static switch_status_t switch_opus_encode_repacketize(switch_codec_t *codec,
        }
 
        if (ret <= 0) {
-               switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Opus encoder: error while repacketizing (out) : %s !\n", opus_strerror(ret));
+               switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Opus encoder: error while repacketizing (out) : %s ! packed nb_frames: %d\n", opus_strerror(ret), opus_repacketizer_get_nb_frames(rp));
                switch_goto_status(SWITCH_STATUS_GENERR, end);
        }
-
+       if (want_fec) {
+               opus_encoder_ctl(context->encoder_object, OPUS_SET_INBAND_FEC(want_fec)); /*restore FEC state*/
+       }
        *encoded_data_len = (uint32_t) ret;
 
 end: