help about pes_packet in transport stream

[kcynice]

I am reading the document about transport stream, iso13838-1.
but i am puzzled about the PES packet structure, there is a slice like:
if (pack_header_field_flag = = '1') {
pack_field_length;//8 bits
pack_header();
}
what pack_header is? where could i get the details or specification about such structure?
thanks

[neuron2]

See Table 2-33 and associated text.

[drmpeg]

I am reading the document about transport stream, iso13838-1.
but i am puzzled about the PES packet structure, there is a slice like:
if (pack_header_field_flag = = '1') {
pack_field_length;//8 bits
pack_header();
}
what pack_header is? where could i get the details or specification about such structure?
thanks
It's so that you can encapsulate PES packets that are originally from an MPEG-1 System Stream or an MPEG-2 Program Stream into the MPEG-2 Transport Stream.

It's very obscure. You may never see a Transport Stream with this syntax.

Also, ISO/IEC 13818-1 describes MPEG-2 Program Streams as well as MPEG-2 Transport Streams. Program Streams (and pack_header) are discussed starting in section 2.5.3.

Ron

[kcynice]

See Table 2-33 and associated text.
I am sorry, i had the modified version of that document, so i didn't see that section. Fortunately, i have just downloaded a original version. I got it.Thanks

[kcynice]

It's so that you can encapsulate PES packets that are originally from an MPEG-1 System Stream or an MPEG-2 Program Stream into the MPEG-2 Transport Stream.

It's very obscure. You may never see a Transport Stream with this syntax.

Also, ISO/IEC 13818-1 describes MPEG-2 Program Streams as well as MPEG-2 Transport Streams. Program Streams (and pack_header) are discussed starting in section 2.5.3.

Ron

You meat that, most of ts has no such structure, right?

And, I have another question, there is a section named PES_packet_length in the specification of PES_packet. iso13818-1 says "A value of 0 indicates that the PES packet length is neither specified nor bounded and is allowed only in PES packets whose payload consists of bytes from a video elementary stream contained in Transport Stream packets.", what's it really mean? does it mean, the value is not 0 only if the payload of ths ts packet is Program Stream?
Thanks