DVB compatible streaming

Streaming over UDP

MWriter example configuration string:

format='dvb' protocol='udp://' video::codec='mpeg2video' video::b='5M' audio::codec='aac'

DVB-compatible MPEG-TS over RTP

The MFormats release notes and MPlatform release notes list DVB-compatible MPEG-TS streaming over RTP as added in SDK version 2.12.0.14909.

Select format='dvb' together with protocol='rtp://'. This mode applies DVB MPEG-TS settings and bitrate smoothing while transmitting MPEG-TS inside RTP packets.

format='dvb' protocol='rtp://' muxrate='7M' video::codec='mpeg2video' video::b='5M' audio::codec='aac' audio::b='128K'

Pass the destination separately from the configuration string. For example, a multicast destination is:

rtp://239.1.2.3:12345

A unicast destination can also be used. Replace the address and port with those required by your receiver.

This configuration differs from format='rtp_mpegts', the ordinary MPEG-TS over RTP mode described in RTP Streaming. Use the explicit format='dvb' protocol='rtp://' combination for the DVB settings and bitrate smoothing described here.

MPlatform: connect a source to MWriter

Configure an existing MWriter instance with WriterNameSet, then connect it to your prepared source with ObjectStart. In this example, pSource is the source object supplying the media.

string destination = "rtp://239.1.2.3:12345";
string configuration = "format='dvb' protocol='rtp://' muxrate='7M' video::codec='mpeg2video' video::b='5M' audio::codec='aac' audio::b='128K'";

m_objWriter.WriterNameSet(destination, configuration);
m_objWriter.ObjectStart(pSource);

MWriter receives media through the connected source. Close the writer with ObjectClose when streaming is finished.

MFormats: submit frames to MFWriter

Configure an existing MFWriter instance with WriterSet. Your application then obtains frames from its source and submits each frame with ReceiverFramePut.

string destination = "rtp://239.1.2.3:12345";
string configuration = "format='dvb' protocol='rtp://' muxrate='7M' video::codec='mpeg2video' video::b='5M' audio::codec='aac' audio::b='128K'";

m_objWriter.WriterSet(destination, 1, configuration);

// In your frame loop, submit each source frame:
m_objWriter.ReceiverFramePut(pFrame, 0, "");

Continue submitting frames for the required streaming duration. Release each frame after processing and close the writer with WriterClose when finished.

Bitrate and network timing

Specify muxrate with enough room for the video, audio and MPEG-TS overhead. The original UDP example uses this estimate:

muxrate = (video_bitrate + audio_bitrate)*1.25

The MPEG-TS stream is padded with null packets to reach the configured transport-stream rate. For example:

format='dvb' protocol='udp://' muxrate='7M' video::codec='mpeg2video' video::b='5M' audio::codec='aac'

For RTP output, muxrate measures the MPEG-TS payload rate. It excludes the RTP header. RTP, UDP, IP and link-layer overhead increase the total network bitrate, so muxrate='7M' does not mean a total network bitrate of exactly 7 Mbit/s.

Keep the connection between the encoder and receiver stable and reliable. Network delivery problems can cause PCR and other timing errors at the receiver.

Program Clock Reference (PCR) provides timing information that the receiver uses to synchronize the stream. Its required repetition interval depends on the applicable standard and stream configuration. See ETSI TS 101 154 for further information.

For example, when an encoder is in network A and its receiver is in network B, assess timing at the receiver as well as at the encoder. A correctly generated stream still needs reliable delivery between the two networks.

DVB streaming attributes

The following table preserves the settings and default values originally documented for UDP streaming. Defaults depend on the SDK version and selected transport; check your writer configuration before relying on them. In particular, these historical UDP defaults are not the defaults for the RTP mode.