PES Headers and Encoder Monitoring

PES header inspection

Packetized Elementary Stream (PES) headers carry metadata about each access unit — timing, stream type, flags, and encoding parameters. Most subscriber devices ignore PES headers entirely to save processing resources. However, when a service has decoding problems that are not explained by CCE, PCR, or PTS errors, PES header fields are worth checking.

PES header information is only available for unscrambled streams — encryption covers the PES header along with the payload.

Navigate to the service's elementary stream in the service tree and select the PES tab to view header fields. The position of the PES section in the interface:

Full PES header field view:

Key PES header fields

Field	Normal value	Impact if wrong
stream_id	Must match the actual stream type (video/audio) per ISO 13818-1 Table 2-22	Decoder may not process the stream
stream_id_name	Descriptive name derived from stream_id	Verify it matches the expected stream type from the multiplexing scheme
PTS_DTS_flag	Must be present	If absent, decoder cannot synchronize presentation timing
PTS	Within the time scale set by PCR	Verify correctness per Bitrates & Timestamps
DTS	Present for video with B-frames; earlier than PTS	Decoder must receive data before it can decode it
PES_packet_length	For video streams, usually 0 (unbounded)	Incorrect non-zero values can cause periodic decoding errors
data_alignment_indicator	Consistent with actual packet structure	Mismatch causes periodic or permanent decoding failure
PES_scrambling_control	0 for modern CAS (Simulcrypt)	Non-zero indicates PES-level scrambling, not supported by Simulcrypt — device may report signal encrypted even when it is not
ESCR_flag	Must be 0	If 1, the ES uses its own synchronization scale; most devices cannot handle this, with effects similar to missing PCR
ES_rate	Must not be 0	Zero is a prohibited value; some decoders may reject the stream
DSM_trick_mode_flag	Must be 0	A value of 1 is non-standard and can theoretically cause decoding failures
PES_CRC_flag	Should be 0	CRC in PES is rarely used in DTV; if unintentionally set, disable in the encoder
PES_extension_flag	Should be 0	PES extensions are rarely used; if unintentionally set, disable in the encoder
stuffing_byte_length	Present for CBR elementary streams	Stuffing is used to equalize bitrate within the ES
copyright	1 if copyright-protected content	Informational; no impact on decoding
original_or_copy	1 = original, 0 = copy	Informational
PES_priority	Usually ignored by decoders	Some decoders may deprioritize or ignore a stream based on this flag

Encoder compression parameters

For elementary streams carrying compressed video or audio, TS Analyzer provides an Encoder section in the ES properties panel:

This shows compression parameters extracted from the bitstream itself. An example of compressed video properties:

Check these values against the multiplexing scheme and encoder settings after any encoder reconfiguration:

• Video codec and profile/level — must match the decoder capabilities of the target subscriber devices.
• Aspect ratio and frame rate — incorrect values cause incorrect display scaling or frame cadence.
• Bit depth / chroma format — must be supported by downstream devices.
• Audio codec, sample rate, and channel configuration — mismatches cause silent or distorted audio.

If compression parameters do not match the encoder's configured settings, the encoder itself may have a fault, or the stream may have been re-encoded by an unexpected device in the chain.