diff options
| author | jcorgan <jcorgan@221aa14e-8319-0410-a670-987f0aec2ac5> | 2006-08-03 04:51:51 +0000 |
|---|---|---|
| committer | jcorgan <jcorgan@221aa14e-8319-0410-a670-987f0aec2ac5> | 2006-08-03 04:51:51 +0000 |
| commit | 5d69a524f81f234b3fbc41d49ba18d6f6886baba (patch) | |
| tree | b71312bf7f1e8d10fef0f3ac6f28784065e73e72 /gr-atsc/src/python/atsc_utils.py | |
Houston, we have a trunk.
git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@3122 221aa14e-8319-0410-a670-987f0aec2ac5
Diffstat (limited to 'gr-atsc/src/python/atsc_utils.py')
| -rw-r--r-- | gr-atsc/src/python/atsc_utils.py | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/gr-atsc/src/python/atsc_utils.py b/gr-atsc/src/python/atsc_utils.py new file mode 100644 index 0000000000..11976640cf --- /dev/null +++ b/gr-atsc/src/python/atsc_utils.py @@ -0,0 +1,74 @@ +# +# Copyright 2006 Free Software Foundation, Inc. +# +# This file is part of GNU Radio +# +# GNU Radio is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 2, or (at your option) +# any later version. +# +# GNU Radio is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with GNU Radio; see the file COPYING. If not, write to +# the Free Software Foundation, Inc., 59 Temple Place - Suite 330, +# Boston, MA 02111-1307, USA. +# + +import random +import sys + +MPEG_SYNC_BYTE = 0x47 + +def make_fake_transport_stream_packet(npkts): + """ + Return a sequence of 8-bit ints that represents an MPEG Transport Stream packet. + + @param npkts: how many 188-byte packets to return + + FYI, each ATSC Data Frame contains two Data Fields, each of which contains + 312 data segments. Each transport stream packet maps to a data segment. + """ + r = [0] * (npkts * 188) + i = 0 + for j in range(npkts): + r[i+0] = MPEG_SYNC_BYTE + r[i+1] = random.randint(0, 127) # top bit (transport error bit) clear + i = i + 2 + for n in range(186): + r[i + n] = random.randint(0, 255) + i = i + 186 + + return r + + +def pad_stream(src, sizeof_total, sizeof_pad): + sizeof_valid = sizeof_total - sizeof_pad + assert sizeof_valid > 0 + assert (len(src) % sizeof_valid) == 0 + npkts = len(src) // sizeof_valid + dst = [0] * (npkts * sizeof_total) + for i in range(npkts): + src_s = i * sizeof_valid + dst_s = i * sizeof_total + dst[dst_s:dst_s + sizeof_valid] = src[src_s:src_s + sizeof_valid] + return dst + + +def depad_stream(src, sizeof_total, sizeof_pad): + sizeof_valid = sizeof_total - sizeof_pad + assert sizeof_valid > 0 + assert (len(src) % sizeof_total) == 0 + npkts = len(src) // sizeof_total + dst = [0] * (npkts * sizeof_valid) + for i in range(npkts): + src_s = i * sizeof_total + dst_s = i * sizeof_valid + dst[dst_s:dst_s + sizeof_valid] = src[src_s:src_s + sizeof_valid] + return dst + + |