[FFmpeg-devel] Avoid MPEG-TS 1-cycle delay

[Paolo Pr]

Hello,

looking at the code of libavformat/mpegtsenc.c I experienced a 1-cycle
delay with the mpegts muxer that could be avoided (at least for Opus codec)
by putting the following lines:
( https://ffmpeg.org/doxygen/4.1/mpegtsenc_8c_source.html#l01777 )

memcpy(ts_st->payload + ts_st->payload_size, buf, size);
ts_st->payload_size += size;
ts_st->opus_queued_samples += opus_samples;

... just above this line (
https://ffmpeg.org/doxygen/4.1/mpegtsenc_8c_source.html#l01734 ):

if (pkt->dts != AV_NOPTS_VALUE) {

Otherwise, at the first muxing cycle, none of the blocks with
mpegts_write_pes() function is executed.
I did not write a patch for that because I don't know if it works with
other codecs as well and I'm not sure if there could be other consequent
issues, but given that Opus can be used with low-latency, it would be good
to consider this.