Extracted hardcoded constants from cast_rtp_stream.

media/cast/cast_defines.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MEDIA_CAST_CAST_DEFINES_H_
 #define MEDIA_CAST_CAST_DEFINES_H_
 
 #include <stdint.h>
 
 #include <cmath>
 #include <map>
 #include <set>
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/logging.h"
 #include "base/time/time.h"
 #include "media/cast/net/cast_transport_config.h"
 
 namespace media {
 namespace cast {
 
 const int64 kDontShowTimeoutMs = 33;

[mcasas, 2015/09/15 16:59:39]

I think this is never used, so please remove.
(But it might be, in unindexed locations)

[msu.koo, 2015/09/17 07:00:50]

Done.

 const float kDefaultCongestionControlBackOff = 0.875f;

[mcasas, 2015/09/15 16:59:39]

This is only used once in [1], suggest moving it there :)

[1]
https://code.google.com/p/chromium/codesearch#chromium/src/media/cast/cast_co...

[msu.koo, 2015/09/17 07:00:50]

Done.

 const uint32 kVideoFrequency = 90000;
+const int kMinSampleRateForEncoding = 8000;

[mcasas, 2015/09/15 16:59:39]

s/int/uint32_t/

I personally like writing 8000u for unsigned constants, but
that's not pervasive in the code base. Just makes it easier
to read IMHO.

[miu, 2015/09/15 22:05:22]

The "int" is more correct, per style guide
(https://google-styleguide.googlecode.com/svn/trunk/cppguide.html#Integer_Types).

We're trying to get rid of uses of unsigned ints in media/cast code wherever we
can (style guide discussion explains why they are bad).  In media/cast code, the
only allowed cases (in new code) are:

1. Bit manipulation, wire-format (de)serialization.  This includes blob/opaque
data (e.g., use of uint8 to indicate byte-sized binary payloads).

2. In cases where size_t should be used.

3. Where wrap-around "counter" semantics are a part of the design (though this
has caused us headaches, and we're looking to replace these unsigneds with class
types).

[msu.koo, 2015/09/17 07:00:50]

Acknowledged.

 const uint32 kStartFrameId = UINT32_C(0xffffffff);
 
 // This is an important system-wide constant.  This limits how much history the
 // implementation must retain in order to process the acknowledgements of past
 // frames.
 // This value is carefully choosen such that it fits in the 8-bits range for
 // frame IDs. It is also less than half of the full 8-bits range such that we
 // can handle wrap around and compare two frame IDs.
 const int kMaxUnackedFrames = 120;
 
@@ skipping 176 matching lines @@
 
 inline int64 TimeDeltaToRtpDelta(base::TimeDelta delta, int rtp_timebase) {
   DCHECK_GT(rtp_timebase, 0);
   return delta * rtp_timebase / base::TimeDelta::FromSeconds(1);
 }
 
 }  // namespace cast
 }  // namespace media
 
 #endif  // MEDIA_CAST_CAST_DEFINES_H_