root/branches/ppalmers-streaming/src/libutil/TimestampedBuffer.h

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1 /*
2  *   FFADO Streaming API
3  *   FFADO = Firewire (pro-)audio for linux
4  *
5  *   http://ffado.sf.net
6  *
7  *   Copyright (C) 2005,2006,2007 Pieter Palmers <pieterpalmers@users.sourceforge.net>
8  *
9  *   This program is free software {} you can redistribute it and/or modify
10  *   it under the terms of the GNU General Public License as published by
11  *   the Free Software Foundation {} either version 2 of the License, or
12  *   (at your option) any later version.
13  *
14  *   This program is distributed in the hope that it will be useful,
15  *   but WITHOUT ANY WARRANTY {} without even the implied warranty of
16  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17  *   GNU General Public License for more details.
18  *
19  *   You should have received a copy of the GNU General Public License
20  *   along with this program {} if not, write to the Free Software
21  *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
22  *
23  *
24  *
25  */
26 #ifndef __FFADO_TIMESTAMPEDBUFFER__
27 #define __FFADO_TIMESTAMPEDBUFFER__
28
29 #include "../debugmodule/debugmodule.h"
30 #include "libutil/ringbuffer.h"
31
32 //typedef float ffado_timestamp_t;
33 //#define TIMESTAMP_FORMAT_SPEC "%14.3f"
34 typedef double ffado_timestamp_t;
35 #define TIMESTAMP_FORMAT_SPEC "%14.3f"
36 // typedef int64_t ffado_timestamp_t;
37 // #define TIMESTAMP_FORMAT_SPEC "%012lld"
38
39 namespace Util {
40
41
42 class TimestampedBufferClient;
43
44 /**
45  * \brief Class implementing a frame buffer that is time-aware
46  *
47  * This class implements a buffer that is time-aware. Whenever new frames
48  * are written to the buffer, the timestamp corresponding to the last frame
49  * in the buffer is updated. This allows to calculate the timestamp of any
50  * other frame in the buffer.
51  *
52  * The buffer is a frame buffer, having the following parameters defining
53  * it's behaviour:
54  * - buff_size: buffer size in frames (setBufferSize())
55  * - events_per_frame: the number of events per frame (setEventsPerFrame())
56  * - event_size: the storage size of the events (in bytes) (setEventSize())
57  *
58  * The total size of the buffer (in bytes) is at least
59  * buff_size*events_per_frame*event_size.
60  *
61  * Timestamp tracking is done by requiring that a timestamp is specified every
62  * time frames are added to the buffer. In combination with the buffer fill and
63  * the frame rate (calculated internally), this allows to calculate the timestamp
64  * of any frame in the buffer. In order to initialize the internal data structures,
65  * the setNominalRate() and setUpdatePeriod() functions are provided.
66  *
67  * \note Currently the class only supports fixed size writes of size update_period.
68  *       This can change in the future, implementation ideas are already in place.
69  *
70  * The TimestampedBuffer class is time unit agnostic. It can handle any time unit
71  * as long as it fits in a 64 bit unsigned integer. The buffer supports wrapped
72  * timestamps using (...).
73  *
74  * There are two methods of reading and writing to the buffer.
75  *
76  * The first method uses conventional readFrames() and writeFrames() functions.
77  *
78  * The second method makes use of the TimestampedBufferClient interface. When a
79  * TimestampedBuffer is created, it is required that a TimestampedBufferClient is
80  * registered. This client implements the processReadBlock and processWriteBlock
81  * functions. These are block processing 'callbacks' that allow zero-copy processing
82  * of the buffer contents. In order to initiate block processing, the
83  * blockProcessWriteFrames and blockProcessReadFrames functions are provided by
84  * TimestampedBuffer.
85  *
86  */
87 class TimestampedBuffer {
88
89 public:
90
91
92     TimestampedBuffer(TimestampedBufferClient *);
93     virtual ~TimestampedBuffer();
94
95     bool writeDummyFrame();
96     bool dropFrames(unsigned int nbframes);
97
98     bool writeFrames(unsigned int nbframes, char *data, ffado_timestamp_t ts);
99     bool readFrames(unsigned int nbframes, char *data);
100
101     bool blockProcessWriteFrames(unsigned int nbframes, ffado_timestamp_t ts);
102     bool blockProcessReadFrames(unsigned int nbframes);
103
104     bool init();
105     bool prepare();
106     bool reset();
107
108     bool isEnabled() {return m_enabled;};
109     void enable() {m_enabled=true;};
110     void disable() {m_enabled=false;};
111
112     bool isTransparent() {return m_transparent;};
113     void setTransparent(bool v) {m_transparent=v;};
114
115     bool setEventSize(unsigned int s);
116     bool setEventsPerFrame(unsigned int s);
117     bool setBufferSize(unsigned int s);
118     unsigned int getBufferSize() {return m_buffer_size;};
119
120     unsigned int getBytesPerFrame() {return m_bytes_per_frame;};
121
122     bool setWrapValue(ffado_timestamp_t w);
123
124     unsigned int getBufferFill();
125
126     // timestamp stuff
127     int getFrameCounter() {return m_framecounter;};
128
129     void getBufferHeadTimestamp(ffado_timestamp_t *ts, signed int *fc);
130     void getBufferTailTimestamp(ffado_timestamp_t *ts, signed int *fc);
131
132     void setBufferTailTimestamp(ffado_timestamp_t new_timestamp);
133     void setBufferHeadTimestamp(ffado_timestamp_t new_timestamp);
134
135     // sync related, also drops or add frames when necessary
136     bool syncBufferHeadToTimestamp(ffado_timestamp_t ts);
137     bool syncBufferTailToTimestamp(ffado_timestamp_t ts);
138     bool syncCorrectLag(int64_t ts);
139    
140     ffado_timestamp_t getTimestampFromTail(int nframes);
141     ffado_timestamp_t getTimestampFromHead(int nframes);
142
143     // buffer offset stuff
144     /// return the tick offset value
145     ffado_timestamp_t getTickOffset() {return m_tick_offset;};
146
147     bool setFrameOffset(int nframes);
148     bool setTickOffset(ffado_timestamp_t);
149
150     // dll stuff
151     bool setNominalRate(float r);
152     float getNominalRate() {return m_nominal_rate;};
153     float getRate();
154
155     bool setUpdatePeriod(unsigned int t);
156
157     // misc stuff
158     void dumpInfo();
159     void setVerboseLevel(int l) {setDebugLevel(l);};
160
161 private:
162     void decrementFrameCounter(int nbframes);
163     void incrementFrameCounter(int nbframes, ffado_timestamp_t new_timestamp);
164     void resetFrameCounter();
165
166 protected:
167
168     ffado_ringbuffer_t * m_event_buffer;
169     char* m_cluster_buffer;
170
171     unsigned int m_event_size; // the size of one event
172     unsigned int m_events_per_frame; // the number of events in a frame
173     unsigned int m_buffer_size; // the number of frames in the buffer
174     unsigned int m_bytes_per_frame;
175     unsigned int m_bytes_per_buffer;
176     bool m_enabled; // you can get frames FIXME: rename!!
177     bool m_transparent; // the buffer should hold the frames put in it. if true, discards all frames
178
179     ffado_timestamp_t m_wrap_at; // value to wrap at
180
181     TimestampedBufferClient *m_Client;
182
183     DECLARE_DEBUG_MODULE;
184
185 private:
186     // the framecounter gives the number of frames in the buffer
187     signed int m_framecounter;
188
189     // the offset that define the timing of the buffer
190     ffado_timestamp_t m_tick_offset;
191
192     // the buffer tail timestamp gives the timestamp of the last frame
193     // that was put into the buffer
194     ffado_timestamp_t   m_buffer_tail_timestamp;
195     ffado_timestamp_t   m_buffer_next_tail_timestamp;
196
197     // this mutex protects the access to the framecounter
198     // and the buffer head timestamp.
199     pthread_mutex_t m_framecounter_lock;
200
201     // tracking DLL variables
202 // JMW: try double for this too
203 //    float m_dll_e2;
204     double m_dll_e2;
205     float m_dll_b;
206     float m_dll_c;
207
208     float m_nominal_rate;
209     unsigned int m_update_period;
210 };
211
212 /**
213  * \brief Interface to be implemented by TimestampedBuffer clients
214  */
215 class TimestampedBufferClient {
216     public:
217         TimestampedBufferClient() {};
218         virtual ~TimestampedBufferClient() {};
219
220         virtual bool processReadBlock(char *data, unsigned int nevents, unsigned int offset)=0;
221         virtual bool processWriteBlock(char *data, unsigned int nevents, unsigned int offset)=0;
222
223 };
224
225 } // end of namespace Util
226
227 #endif /* __FFADO_TIMESTAMPEDBUFFER__ */
228
229
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