Re: [Discuss-gnuradio] WARN: transport stream sync error

most of the udp packets i recieve are 1472 bytes

it is a good idea to start sniffing the udp stream with wireshark, maybe i can see something strange on it.

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Van: "Ron Economos" <w6rz@comcast.net>
Aan: "discuss-gnuradio" <discuss-gnuradio@gnu.org>
Verzonden: Woensdag 26 april 2017 21:21:39
Onderwerp: Re: [Discuss-gnuradio] WARN: transport stream sync error

You may want to put a file sink block after your ZMQ block to make sure you're chain is working as expected.

Usually 188 byte alignment is just done by picking a UDP packet size that's a multiple of 188 bytes (plus overhead). For example, VLC in UDP mode uses 1358 byte packets and puts 7 TS packets in each UDP packet. Like so:



Ron

On 04/26/2017 11:52 AM, on4bhm@telenet.be wrote:

Are you saying that there are no sync bytes in my stream?

or should i wait until i get byte 0x47 in my udp packet, wait till i get 188 bytes, and send them as an array of bytes in the zeroMQ?

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Van: "Ron Economos" <w6rz@comcast.net>
Aan: "discuss-gnuradio" <discuss-gnuradio@gnu.org>
Verzonden: Woensdag 26 april 2017 20:16:10
Onderwerp: Re: [Discuss-gnuradio] WARN: transport stream sync error

The BBheader block expects the Transport Stream to start with a sync byte (0x47) and that a sync byte appears every 188 bytes.

There's no sync byte synchronization in the BBheader block, so if the stream doesn't start with a sync byte, you'll get continuous errors.

Ron

On 04/26/2017 10:56 AM, on4bhm@telenet.be wrote:

Hi,

My setup:

Linux gnuradio with dvb-s2 tx sample code. adjusted to read from ZeroMQ pull source

5M symbol. in 8psk dvb-s2 3/4 code rate

Windows side: 2 programs:

1) program to make udpts stream from webcam(5M) -> send udp stream to 127.0.0.1:1234

2) program to listen to udp port 1234 get udp packets and send them to ZeroMQ push socket

gnuradio is complaining about transport stream sync error.

What can be the reason for this?

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