MP2: Bugfix: low latency streams audio broken (poor pts timing calcul…

…ations - fixed).

encoders/audio/mp2/twolame.c

@@ -208,16 +208,19 @@ static void *start_encoder_mp2( void *ptr )
             av_fifo_generic_read( fifo, coded_frame->data, frame_size, NULL );
             memcpy(&coded_frame->avfm, &avfm, sizeof(avfm));
 
-            /* a = (27000000 / 1000) * 96 - Calculate 96ms in units of a 27MHz clock.
-             * a = 2592000
-             * Output PTS packets (27MHz) are rounded to nearest 96ms interval on a 27MHz clock.
+            /* In  low latency mode, obe configures a single MP2 frame in every pes (enc_params->frames_per_pes), with a PTS interval of 24ms.
+             * In norm latency mode, obe configures        N MP2 frames in every pes, with a PTS interval of N*24ms.
+             * Typically, we see 96MS PTS increments in the transport packets, buts its equally valid to see 24ms.
+             * Depending on what latency mode we're in, we need to round to the nearest '24ms or N*' interval.
+             * Output PTS packets (27MHz) are rounded to nearest 24ms or N*24ms (typically 96ms for norm lat) interval on a 27MHz clock.
              */
             /* The outgoing PTS is rounded and based on recent h/w clock, so massive leaps in
              * the h/w clock are automatically compensated for.
+             * 648000 represents number of ticks in 27Mhz clock for 24ms, the smallest MP2 framesize we can deliver.
              */
-            int64_t rounded_pts = av_rescale(coded_frame->avfm.audio_pts, OBE_CLOCK, 2592000);
+            int64_t rounded_pts = av_rescale(coded_frame->avfm.audio_pts, OBE_CLOCK, 648000 * enc_params->frames_per_pes);
             rounded_pts /= OBE_CLOCK;
-            rounded_pts *= 2592000;
+            rounded_pts *= (648000 * enc_params->frames_per_pes);
             coded_frame->pts = rounded_pts;
             coded_frame->pts += ((int64_t)stream->audio_offset_ms * 27000);