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Code Issues Releases Wiki Activity

Implemented backtracing for fast forward/rewind

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This commit is contained in:
Klaus Schmidinger 2001-09-09 13:36:16 +02:00
parent de45b51473
commit b47ce65b03
3 changed files with 65 additions and 6 deletions
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1
CONTRIBUTORS
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@ -101,6 +101,7 @@ Stefan Huelswitt <huels@iname.com>
for making the width and height of the OSD configurable
for implementing the "Jump" function in replay mode
for implementing "Multi Speed Mode"
for implementing backtracing for fast forward/rewind
Ulrich Röder <dynamite@efr-net.de>
for pointing out that there are channels that have a symbol rate higher than

2
HISTORY
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@ -735,3 +735,5 @@ Video Disk Recorder Revision History
- Switching through channel groups with the "Left" and "Right" keys now
always starts at the group that contains the current channel.
- Implemented "Multi Speed Mode" (thanks to Stefan Huelswitt).
- Implemented backtracing to hit the right spot after fast forward/rewind
(thanks to Stefan Huelswitt).

66
dvbapi.c
View File

@ -7,7 +7,7 @@
* DVD support initially written by Andreas Schultz <aschultz@warp10.net>
* based on dvdplayer-0.5 by Matjaz Thaler <matjaz.thaler@guest.arnes.si>
*
* $Id: dvbapi.c 1.113 2001/09/09 12:52:41 kls Exp $
* $Id: dvbapi.c 1.114 2001/09/09 13:34:41 kls Exp $
*/
//#define DVDDEBUG 1
@ -628,11 +628,68 @@ int ReadFrame(int f, uchar *b, int Length, int Max)
return r;
}
// --- cBackTrace ----------------------------------------------------------
#define AVG_FRAME_SIZE 15000 // an assumption about the average frame size
#define DVB_BUF_SIZE (256 * 1024) // an assumption about the dvb firmware buffer size
#define BACKTRACE_ENTRIES (DVB_BUF_SIZE / AVG_FRAME_SIZE + 20) // how many entries are needed to backtrace buffer contents
class cBackTrace {
private:
int index[BACKTRACE_ENTRIES];
int length[BACKTRACE_ENTRIES];
int pos, num;
public:
cBackTrace(void);
void Clear(void);
void Add(int Index, int Length);
int Get(bool Forward);
};
cBackTrace::cBackTrace(void)
{
Clear();
}
void cBackTrace::Clear(void)
{
pos = num = 0;
}
void cBackTrace::Add(int Index, int Length)
{
index[pos] = Index;
length[pos] = Length;
if (++pos >= BACKTRACE_ENTRIES)
pos = 0;
if (num < BACKTRACE_ENTRIES)
num++;
}
int cBackTrace::Get(bool Forward)
{
int p = pos;
int n = num;
int l = DVB_BUF_SIZE + (Forward ? 0 : 256 * 1024); //XXX (256 * 1024) == DVB_BUF_SIZE ???
int i = -1;
while (n && l > 0) {
if (--p < 0)
p = BACKTRACE_ENTRIES - 1;
i = index[p] - 1;
l -= length[p];
n--;
}
return i;
}
// --- cPlayBuffer ---------------------------------------------------------
#define MAX_VIDEO_SLOWMOTION 63 // max. arg to pass to VIDEO_SLOWMOTION // TODO is this value correct?
class cPlayBuffer : public cRingBufferFrame {
private:
cBackTrace backTrace;
protected:
enum ePlayModes { pmPlay, pmPause, pmSlow, pmFast, pmStill };
enum ePlayDirs { pdForward, pdBackward };
@ -729,6 +786,7 @@ void cPlayBuffer::Output(void)
}
}
writeIndex = frame->Index();
backTrace.Add(frame->Index(), frame->Count());
Drop(frame);
}
}
@ -766,6 +824,7 @@ void cPlayBuffer::Empty(bool Block)
while ((blockInput > 1 || blockOutput > 1) && time(NULL) - t0 < 2)
usleep(1);
Lock();
if ((readIndex = backTrace.Get(playDir == pdForward)) < 0)
readIndex = writeIndex;
cRingBufferFrame::Clear();
CHECK(ioctl(videoDev, VIDEO_CLEAR_BUFFER));
@ -773,6 +832,7 @@ void cPlayBuffer::Empty(bool Block)
}
if (!Block) {
blockInput = blockOutput = 0;
backTrace.Clear();
Unlock();
}
}
@ -830,10 +890,6 @@ void cPlayBuffer::Forward(void)
TrickSpeed(Setup.MultiSpeedMode ? -1 : -MAX_SPEEDS);
break;
case pmFast:
//XXX
if (playDir == pdForward)
readIndex -= 150; // this about compensates for the buffered data, so that we don't get too far ahead
//XXX
if (Setup.MultiSpeedMode)
TrickSpeed(playDir == pdForward ? 1 : -1);
else if (playDir == pdForward)