Name
dvbsnoop - DVB and MPEG stream analyzer
SYNOPSIS
dvbsnoop [-s mode] [options] pid
dvbsnoop [-s mode] [options] -if filename [pid]
dvbsnoop [-s mode] [options] -b [pid] > binary.file
dvbsnoop [-s mode] [options]
Description
DVBSNOOP is a text based DVB and MPEG stream analyzer for
viewing/debugging stream information, e.g. send via digital TV. You may
also use dvbsnoop to analyze mpeg compliant streams stored on DVD or
other media. Dvbsnoop analyzes and displays MPEG, DVB, DSM-CC, MHP,
etc. data and structures in human readable form. Possible stream types
are TS (tranport streams), PS (program streams), PES (packetized
elementary streams) or SECTIONS (service information streams).
DVBSNOOP also has some additional functionality to analyze receiver
(set top box, dvb card) data, bandwidth of a transport stream, pid
scan, etc.
Using special network programs like netcat (nc), dvbsnoop may also be
used to do remote sniffing and decoding. For post-processing dvbsnoop
output, you may use the full range of unix tools and scripting
languages (grep, perl, python, mrtg, gnuplot, etc.).
Usage
Dvbsnoop provides an online and offline input and different
snoop/decoding modes (see below).
Using dvbsnoop ’online’ requires dvb-api compliant devices
(http://www.linuxtv.org) to grab live stream information from e.g.
satellite or cable tv or data streams. You will also need DVB compliant
hardware (e.g. DVB-S pci card or a linux based setop box like dbox2 or
Dreambox) to receive DVB data streams. To tune into a transponder or
frequency, please use a program like ’szap’, ’dvbtune’ or a DVB-GUI
like ’Enigma’, ’Neutrino’, ’MythTV’, ’VDR’, etc..
The ’offline’ mode enables you to analyze binary stream files (e.g.
transport stream files or PES files).
Some options are specific for the selected modes. You may try different
combinations of command line options to get best results.
A short FAQ for common questions and example decoding output can be
found at http://dvbsnoop.sourceforge.net.
Basic Decoding Selection Mode Command Line Options
-s [ts|ps|pes|sec|pidscan|bandwidth|signal|feinfo]
Basic snoop mode selection.
sec = SI mode (SECTIONS)
ts = transport stream mode
ps = program stream mode (same as PES mode)
pes = packetized elementary stream mode,
e.g. teletext, audio, video, data
pidscan = scan and display PIDs on tuned
transponder/frequency.
bandwidth = bandwidth measurement mode
for selected pid.
signal = display tuner signal reception info.
feinfo = display tuner data (frontend info).
The modes ’sec’, "ps" or "pes" require the selection of a PID.
The mode ’ts’ requires either a PID specified or the option
-tsraw.
A PID can be specified using octal, decimal or hexadecimal
values. Examples: octal: 021, decimal: 17, hexadecimal: 0x11
If -s option is omitted, default mode is "-s sec" (Section
mode).
General Command Line Options
-help
Print help text with command line options.
-hideproginfo
Do not print dvbsnoop header (version, etc.).
General Decoding Output Command Line Options
-pd <mode>
Specify print decoding verbose mode. Specify 0 for no output. 9
will be very verbose. Default is 6.
-npd
Same as -pd 0.
-ph <mode>
Specify print hex output verbose mode:
0=no hexdump output, 1=hex output, 2=hex line,
3=ascii line, 4=alternate hex output. (default is 4)
-hexdumpbuffer
-nohexdumpbuffer
Switch on/off hexdump of stream input buffer. May be used to
enhance -ph option. (e.g. -ph 4 -nohexdumpbuffer)
-nph
Obsolete, same as -nohexdumpbuffer.
-t<mode>
Timestamp output mode:
-tf = full timestamp
-td = delta timestamp mode,
-tn = no time stamp.
-b
Binary output of packets (disables other output). Use this
option to store raw data in file or chain data to another
program.
E.g.: dvbsnoop -s ts 0x00 -b > file
dvbsnoop -s pes 0x3FF -b | ./myprogram
There might be a file limit on your system (mostly 2 GB) when
writing files using ’>’.
Device Selection Command Line Options
Dvbsnoop uses default devices, defined by the DVB API. On some
platforms or if using multiple dvb cards, you may want to override
default settings, e.g. to select a different tuner.
-demux <device>
Specify <device> for demux. If not specified, dvbsnoop uses the
device specified by the linux dvb-api.
-dvr <device>
Specify <device> for dvr. If not specified, dvbsnoop uses the
device specified by the linux dvb-api.
-frontend <device>
Specify <device> for frontend. If not specified, dvbsnoop uses
the device specified by the linux dvb-api.
-adapter <n>
Specify DVB adapter/card by number <n> (0-9) using default path
pattern (e.g. /dev/dvb/adapter1/...). If not specified, dvbsnoop
uses the default adapter/card - usually 0.
-devnr <n>
Specify DVB device number <n> (0-9) on a DVB adapter/card using
default path pattern (e.g. /dev/dvb/adapt.../demux1). If not
specified, dvbsnoop uses the default device number - usually 0.
-buffersize <kb>
Set demux read buffer size in KBytes. Default is 0 (use
internal default value).
-n <value>
Stop after reading <value> packets. Use this to limit the read
process. Default is 0 (no limit).
-if <file>
Read binary stream data from file instead of the demux device.
<file> = ’-’ reads from standard input. Depending on the
decoding mode this might be transport stream, packetized
elementary stream or sections. Please aware, that you cannot
e.g. use -s pes or -s sec on a saved transport stream. The
decoding/snooping mode has to match the saved stream format!
SECTION Mode (SEC) Specific Command Line Options
The following command line options are special to the ’SECTION’
decoding mode:
-s sec
Section mode.
-timeout <ms>
Section read timeout in ms. Default is 0 (no timeout).
-f <filter>
Filter value for filtering section data e.g. table id’s. Value
may be decimal (49), octal (037) or hexadecimal (0x4F). You may
use multibyte filters like: 0x4E.01.20.FF The filter comprises
e.g. 16 bytes covering byte 0 and byte 3..17 in a section, thus
excluding bytes 1 and 2 (the length field of a section). To
check the filter values use -pd 9.
-m <mask>
Mask value to use for filters. Value may be decimal (49), octal
(037) or hexadecimal (0x4F). You may use multibyte filters
like: 0xFF.F0.FE.FF The filter comprises e.g. 16 bytes covering
byte 0 and byte 3..17 in a section, thus excluding bytes 1 and 2
(the length field of a section). To check the filter values use
-pd 9.
-N <value>
Stop after decoding <value> packets. Use this to limit the
packet decoding process. Useful, when reading stream data from
file. -n limits the read packet process, -N limits the decoding
process. Using dvb hardware filters -n would be the same as -N.
Default is 0 (no limit).
-crc
Do CRC checking, when reading section data. Default is off.
This is only supported, if your DVB hardware/firmware supports
CRC checking. Remark: Some section types may use Checksum
instead of CRC.
-nocrc
Don’t do hardware/firmware CRC, when reading section data
(default). Some DVB sections do not have proper CRC set!
-softcrc
Do soft CRC checking, when reading section data.
Hardware/firmware CRC should be preferred. Default is
-nosoftcrc. Remark: Some section types may use Checksum instead
of CRC.
-nosoftcrc
Don’t do soft CRC, when reading sections. (default)
-spiderpid
Snoop referenced section PIDs. This option recursively reads
all PIDs referenced by a section. This option also sets number
of packets to be read to 1 (sets -n 1). To read more packets for
a pid, use -n <count> after specifying -spiderpid.
-privateprovider <id>
Set provider <id> string for decoding of special private tables
and descriptors. Use -help to display provider currently
supported. If omitted, private data will be displayed as hexdump
depending on -ph option. (If you have information on private
data structures, currently not supported by dvbsnoop, please let
us know!)
Transport Stream (TS) Mode Specific Command Line Options
The following command line options are special to the ’Transport
Stream’ decoding mode:
-s ts
Transport Stream mode.
-sync
(obsolete as of 1.4.10, -sync is default. This option enforces
software packet sync for TS and PS/PES).
-nosync
(obsolete as of 1.4.10).
-tssubdecode
Sub-decode SI data (sections) or PS/PES data from transport
stream decoding. This reads transport stream packets and tries
to decode its content. Useful to decode PES or SI data from a
transport stream file.
-tsraw
Read full transport stream (all pids). Your hardware/firmware
has to support this mode.
-N <value>
Stop after decoding <value> packets. Use this to limit the
packet decoding process. Useful, when reading stream data from
file. -n limits the read packet process, -N limits the decoding
process. Using dvb hardware filters -n would be the same as -N.
Default is 0 (no limit).
PES or PS Mode Specific Command Line Options
The following command line options are special to the ’PES’ (packetized
elementary stream) or ’PS’ (program stream) decoding mode:
-s ps Program Stream mode.
-s pes
Packetized Elementary Stream mode.
-sync
(obsolete as of 1.4.10, -sync is default. This option enforces
software packet sync for TS and PS/PES).
-nosync
(obsolete as of 1.4.10).
PID Scan Mode Specific Command Line Options
The following command line options are special to the ’PID Scan’
discovery mode:
-s pidscan
Scan PIDs on transponder/frequency.
-maxdmx <n>
Set maximum use of DMX filters. Default is 0 (use all possible
filters).
Bandwidth Mode Specific Command Line Options
There are no special command line options for the ’Bandwidth’ display
mode.
-s bandwidth
Determine bandwidth for a dvb stream. This will be done by
calculating received ts packets in a timeslot.
Signal Mode Specific Command Line Options
There are no special command line options for the ’Signal Strength’
display mode.
-s signal
Poll frontend signal status.
-timeout <ms>
Poll timing in msec.
Frontend Info Mode Specific Command Line Options
There are no special command line options for the ’Frontend Info’
display mode.
-s feinfo
Display frontend information.
Examples
Examples how to use dvbsnoop:
Display EPG, 10 sections:
dvbsnoop -s sec -nph -n 10 0x12
dvbsnoop -s sec -ph 3 -n 10 -crc 0x12
Display sections tree (1 packet each) using private provider data:
dvbsnoop -s sec -spiderpid -privateprovider premiere.de 0x00
Display sections tree (1 packet each) skipping "empty" pids:
dvbsnoop -s sec -spiderpid -timeout 15000 0x00
Display PAT transport stream (ts) and do subdecoding of sections and
descriptors:
dvbsnoop -s ts -pd 4 -tssubdecode -nph 0x00
Read PES (e.g. Videotext, Video, Audio) stream:
dvbsnoop -s pes 0x28F
dvbsnoop -s pes 0x28F -b > pes.bin.file
Read PS from file and do not show hex dump:
dvbsnoop -if hdtv_ps_file.mpg -s ps -ph 0 -nohexdumpbuffer -n 30
Show current signal strength:
dvbsnoop -s signal
dvbsnoop -s signal -pd 9 -n 100 -timeout 100
Show bandwidth usage of a PID 0x1FF:
dvbsnoop -s bandwidth -n 1000 -pd 2 0x1FF
dvbsnoop -s bandwidth -buffersize 256 -n 1000 0x1FF
Do PID scan of a tuned transponder (different display levels):
dvbsnoop -s pidscan -pd 1
dvbsnoop -s pidscan -pd 6
dvbsnoop -s pidscan -pd 9 -maxdmx 12
Show frontend info:
dvbsnoop -s feinfo -pd 9
Try to scan all sections, read 2 packets per PID:
dvbsnoop -nohexdumpbuffer -spiderpid -n 2 0x0000
Save 1000 packets of a transport stream to a file:
dvbsnoop -b -n 1000 -s ts 0x200 > ts_file.pid0x200.bin
dvbsnoop -b -n 1000 -s ts -tsraw > ts_file.bin
Read transport stream (ts) from file and decode:
dvbsnoop -s ts -if ts_stream.bin
dvbsnoop -s ts -if ts_file.pid0x200.bin 0x200
Simple filter for some PID values, some examples:
dvbsnoop -n 5 -nph 0x00 | grep -i "PID: "
dvbsnoop -spiderpid -nph -n 10 0x00 | grep -i "PID: " | sort | uniq
dvbsnoop -s signal -pd 9 | ./perl-statistics-prog.pl
Other simple filter examples:
dvbsnoop -s sec -f 0x4E -m 0xFF 0x12
dvbsnoop -s sec -f 0x4E.34.00 -m 0xFF.FF.0F 0x12
dvbsnoop -s sec -f 16.00 -m 255.255 0x12
dvbsnoop -s sec -nph -n 5 0x10 | grep -i "frequency"
dvbsnoop -s ts -nph 0x100 | grep -i ’Transport_error\|^PID’
Selecting devices:
dvbsnoop -s feinfo -pd 9 -frontend /dev/dvb/adapter0/frontend1
dvbsnoop -s feinfo -pd 9 -adapter 0 -devnr 1
dvbsnoop -s feinfo -pd 9 -adapter 2
Sending dvbsnoop data over network, using netcat:
dvbsnoop -s pes 0x28F -b nc -q ServerName 31337
Do remote decoding of dvb data over network using dvbsnoop and netcat:
streaming site:
dvbsnoop -s ts 0x0065 -b nc -q ServerName 31000
receiving site:
nc -l -p 31000 dvbsnoop -nph -s ts -tssubdecode -if -
You may also use e.g. dvbtools for sending dvb data over a network:
dvbstream .... --> dumprtp dvbsnoop -s ts -if -
NOTES
dvbsnoop tries to decode all of the data it receives, e.g. if you try
to decode a video or audio stream in section mode, dvbsnoop may assume
a section table and will decode the data wrong. In this case the
decoding will be garbage. Using the ’-crc’ option should prevent this
(if supported at the hardware/driver level).
dvbsnoop does not do DVB stream validation. dvbsnoop assumes correct
DVB streams. Corrupted streams or streams with wrong semantics (e.g.
incorrect length information) will result in wrong decoding output. For
this reason, the use of ’-crc’ options is strongly recommended.
Depending on the firmware of your dvb card, dvbsnoop may not be able to
sniff on pids, which are occupied by other processes. This is no bug,
this is a driver/firmware issue.
SIGNALS
dvbsnoop catches signals to provide smooth program termination.
SIGHUP, SIGQUIT and SIGTERM will terminate dvbsnoop smoothly.
SIGABORT will abort at once after flushing buffers.
SIGKILL will just kill down dvbsnoop (OS specific).
BUGS
Please check http://dvbsnoop.sourceforge.net for bug reports.
Bug reports: http://sourceforge.net/tracker/?group_id=85040
SEE ALSO
dvbtune (1), dvbstream (1).
Acknowledgments
DVBSNOOP was written by Rainer Scherg (rasc).
Copyright (c) 2001-2006 Rainer Scherg
Additional patches and bugfixes/-reports were provided by members of
the tuxbox project - bringing digital TV to linux based set top boxes
(e.g. "dbox2" digital tv receiver) and also by users of dvbsnoop (see
the ChangeLog file for credits).
For more information about DVBSNOOP please visit
’http://dvbsnoop.sourceforge.net’.