From 5d69a524f81f234b3fbc41d49ba18d6f6886baba Mon Sep 17 00:00:00 2001
From: jcorgan <jcorgan@221aa14e-8319-0410-a670-987f0aec2ac5>
Date: Thu, 3 Aug 2006 04:51:51 +0000
Subject: Houston, we have a trunk.

git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@3122 221aa14e-8319-0410-a670-987f0aec2ac5
---
 gr-atsc/src/python/atsc_utils.py | 74 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 74 insertions(+)
 create mode 100644 gr-atsc/src/python/atsc_utils.py

(limited to 'gr-atsc/src/python/atsc_utils.py')

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
+
+
-- 
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