diff options
| author | Tom Rondeau <trondeau@vt.edu> | 2013-03-15 20:49:05 -0400 |
|---|---|---|
| committer | Tom Rondeau <trondeau@vt.edu> | 2013-03-15 20:49:05 -0400 |
| commit | 3d38e82e7d87dfc01132b199e33b53add8a706fa (patch) | |
| tree | af4545bcf3cea24dc30571601116a3a89381ad5d /gr-atsc/python/atsc_utils.py | |
| parent | 39ff6d4814c858f2dbaf3c8007940872c46d6c95 (diff) | |
atsc: adjustments to atsc to start to conform to v3.7 structure.
Not going to comply completely with the new structure; just wanted to get it so that it looked more consistent once installed.
Diffstat (limited to 'gr-atsc/python/atsc_utils.py')
| -rw-r--r-- | gr-atsc/python/atsc_utils.py | 75 |
1 files changed, 75 insertions, 0 deletions
diff --git a/gr-atsc/python/atsc_utils.py b/gr-atsc/python/atsc_utils.py new file mode 100644 index 0000000000..fc2465bed2 --- /dev/null +++ b/gr-atsc/python/atsc_utils.py @@ -0,0 +1,75 @@ +# +# 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 3, 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., 51 Franklin Street, +# Boston, MA 02110-1301, 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. + + Args: + 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 + + |