1 /*
2 * encoder-adpcm.cc --
3 *
4 * FIXME: This file needs a description here.
5 *
6 * Copyright (c) 1995-2002 The Regents of the University of California.
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions are met:
11 *
12 * A. Redistributions of source code must retain the above copyright notice,
13 * this list of conditions and the following disclaimer.
14 * B. Redistributions in binary form must reproduce the above copyright notice,
15 * this list of conditions and the following disclaimer in the documentation
16 * and/or other materials provided with the distribution.
17 * C. Neither the names of the copyright holders nor the names of its
18 * contributors may be used to endorse or promote products derived from this
19 * software without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS
22 * IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
23 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
24 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE
25 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
26 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
27 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
30 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
31 * POSSIBILITY OF SUCH DAMAGE.
32 */
33
34 static const char rcsid[] =
35 "@(#) $Header: /usr/mash/src/repository/mash/mash-1/audio/encoder-adpcm.cc,v 1.8 2003/11/19 19:20:14 aswan Exp $";
36
37 #include <string.h>
38 #include "rtp/config.h"
39 #include "rtp/rtp.h"
40 #include "audio/encoder.h"
41 #include "rtp/pktbuf-rtp.h"
42 extern "C" {
43 #include "audio/adpcm.h"
44 }
45
46 class ADPCMEncoder : public PCM_Encoder {
47 public:
48 ADPCMEncoder();
49 virtual void encode(u_int32_t ts, u_int8_t* samples, int cc);
50 protected:
51 adpcm_state tstate_;
52 };
53
54 static class ADPCMEncoderClass : public TclClass {
55 public:
56 ADPCMEncoderClass() : TclClass("Module/AudioEncoder/ADPCM") {}
57 TclObject* create(int /* argc */, const char*const* /* argv */) {
58 return (new ADPCMEncoder);
59 }
60 } adpcm_encoder_class;
61
62
63 ADPCMEncoder::ADPCMEncoder()
64 {
65 memset((char*)&tstate_, 0, sizeof(tstate_));
66 }
67
68 void ADPCMEncoder::encode(u_int32_t ts, u_int8_t* frame, int len)
69 {
70 register int marker = (ts != last_ts_) ? htons(RTP_M) : 0;
71 last_ts_ = ts + len;
72
73 pktbuf* pb = pool_->alloc(ts, RTP_PT_DVI);
74 rtphdr* rh = (rtphdr*)pb->data;
75 rh->rh_flags |= marker;
76 u_int8_t* o = (u_int8_t*)(rh + 1);
77 *(struct adpcm_state*)o = tstate_;
78 HTONS(((struct adpcm_state*)o)->valprev);
79 adpcm_coder(frame, o + sizeof(struct adpcm_state), len, &tstate_);
80 len = (len >> 1) + sizeof(struct adpcm_state);
81 pb->len = len + sizeof(*rh);
82 target_->recv(pb);
83 }
84
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