103 lines
3.4 KiB
Python
103 lines
3.4 KiB
Python
"""
|
|
MPEG-2 Transport Stream parser.
|
|
|
|
Documentation:
|
|
- MPEG-2 Transmission
|
|
http://erg.abdn.ac.uk/research/future-net/digital-video/mpeg2-trans.html
|
|
|
|
Author: Victor Stinner
|
|
Creation date: 13 january 2007
|
|
"""
|
|
|
|
from lib.hachoir_parser import Parser
|
|
from lib.hachoir_core.field import (FieldSet, ParserError, MissingField,
|
|
UInt8, Enum, Bit, Bits, RawBytes)
|
|
from lib.hachoir_core.endian import BIG_ENDIAN
|
|
from lib.hachoir_core.text_handler import textHandler, hexadecimal
|
|
|
|
class Packet(FieldSet):
|
|
def __init__(self, *args):
|
|
FieldSet.__init__(self, *args)
|
|
if self["has_error"].value:
|
|
self._size = 204*8
|
|
else:
|
|
self._size = 188*8
|
|
|
|
PID = {
|
|
0x0000: "Program Association Table (PAT)",
|
|
0x0001: "Conditional Access Table (CAT)",
|
|
# 0x0002..0x000f: reserved
|
|
# 0x0010..0x1FFE: network PID, program map PID, elementary PID, etc.
|
|
# TODO: Check above values
|
|
#0x0044: "video",
|
|
#0x0045: "audio",
|
|
0x1FFF: "Null packet",
|
|
}
|
|
|
|
def createFields(self):
|
|
yield textHandler(UInt8(self, "sync", 8), hexadecimal)
|
|
if self["sync"].value != 0x47:
|
|
raise ParserError("MPEG-2 TS: Invalid synchronization byte")
|
|
yield Bit(self, "has_error")
|
|
yield Bit(self, "payload_unit_start")
|
|
yield Bit(self, "priority")
|
|
yield Enum(textHandler(Bits(self, "pid", 13, "Program identifier"), hexadecimal), self.PID)
|
|
yield Bits(self, "scrambling_control", 2)
|
|
yield Bit(self, "has_adaptation")
|
|
yield Bit(self, "has_payload")
|
|
yield Bits(self, "counter", 4)
|
|
yield RawBytes(self, "payload", 184)
|
|
if self["has_error"].value:
|
|
yield RawBytes(self, "error_correction", 16)
|
|
|
|
def createDescription(self):
|
|
text = "Packet: PID %s" % self["pid"].display
|
|
if self["payload_unit_start"].value:
|
|
text += ", start of payload"
|
|
return text
|
|
|
|
def isValid(self):
|
|
if not self["has_payload"].value and not self["has_adaptation"].value:
|
|
return u"No payload and no adaptation"
|
|
pid = self["pid"].value
|
|
if (0x0002 <= pid <= 0x000f) or (0x2000 <= pid):
|
|
return u"Invalid program identifier (%s)" % self["pid"].display
|
|
return ""
|
|
|
|
class MPEG_TS(Parser):
|
|
PARSER_TAGS = {
|
|
"id": "mpeg_ts",
|
|
"category": "video",
|
|
"file_ext": ("ts",),
|
|
"min_size": 188*8,
|
|
"description": u"MPEG-2 Transport Stream"
|
|
}
|
|
endian = BIG_ENDIAN
|
|
|
|
def validate(self):
|
|
sync = self.stream.searchBytes("\x47", 0, 204*8)
|
|
if sync is None:
|
|
return "Unable to find synchronization byte"
|
|
for index in xrange(5):
|
|
try:
|
|
packet = self["packet[%u]" % index]
|
|
except (ParserError, MissingField):
|
|
if index and self.eof:
|
|
return True
|
|
else:
|
|
return "Unable to get packet #%u" % index
|
|
err = packet.isValid()
|
|
if err:
|
|
return "Packet #%u is invalid: %s" % (index, err)
|
|
return True
|
|
|
|
def createFields(self):
|
|
sync = self.stream.searchBytes("\x47", 0, 204*8)
|
|
if sync is None:
|
|
raise ParserError("Unable to find synchronization byte")
|
|
elif sync:
|
|
yield RawBytes(self, "incomplete_packet", sync//8)
|
|
while not self.eof:
|
|
yield Packet(self, "packet[]")
|
|
|