liveMedia/MPEG1or2FileServerDemux.cpp File Reference

#include "MPEG1or2FileServerDemux.hh"
#include "MPEG1or2DemuxedServerMediaSubsession.hh"
#include "ByteStreamFileSource.hh"

Include dependency graph for MPEG1or2FileServerDemux.cpp:

Go to the source code of this file.

Data Structures
class	DummySink
Defines
#define	DUMMY_SINK_BUFFER_SIZE   (6+65535)
Functions
static float	MPEG1or2ProgramStreamFileDuration (UsageEnvironment &env, char const *fileName, unsigned &fileSize)
static Boolean	getMPEG1or2TimeCode (FramedSource *dataSource, MPEG1or2Demux &parentDemux, Boolean returnFirstSeenCode, float &timeCode)
static void	afterPlayingDummySink (DummySink *sink)
static float	computeSCRTimeCode (MPEG1or2Demux::SCR const &scr)

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Define Documentation

#define DUMMY_SINK_BUFFER_SIZE   (6+65535)

Definition at line 166 of file MPEG1or2FileServerDemux.cpp.

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Function Documentation

static void afterPlayingDummySink

(

DummySink *

sink

)

[static]

Definition at line 250 of file MPEG1or2FileServerDemux.cpp.

References DummySink::watchVariable.

Referenced by getMPEG1or2TimeCode().

                                                   {
  // Return from the "doEventLoop()" call:
  sink->watchVariable = ~0;
}

static float computeSCRTimeCode

(

MPEG1or2Demux::SCR const &

scr

)

[static]

Definition at line 255 of file MPEG1or2FileServerDemux.cpp.

References MPEG1or2Demux::SCR::extension, MPEG1or2Demux::SCR::highBit, and MPEG1or2Demux::SCR::remainingBits.

Referenced by getMPEG1or2TimeCode().

                                                             {
  double result = scr.remainingBits/90000.0 + scr.extension/300.0;
  if (scr.highBit) {
    // Add (2^32)/90000 == (2^28)/5625
    double const highBitValue = (256*1024*1024)/5625.0;
    result += highBitValue;
  }

  return (float)result;
}

static Boolean getMPEG1or2TimeCode	(	FramedSource *	dataSource,
		MPEG1or2Demux &	parentDemux,
		Boolean	returnFirstSeenCode,
		float &	timeCode
	)			[static]

Definition at line 195 of file MPEG1or2FileServerDemux.cpp.

References afterPlayingDummySink(), computeSCRTimeCode(), TaskScheduler::doEventLoop(), env, Medium::envir(), False, MPEG1or2Demux::lastSeenSCR(), MediaSink::startPlaying(), UsageEnvironment::taskScheduler(), and DummySink::watchVariable.

Referenced by MPEG1or2ProgramStreamFileDuration().

                                                    {
  // Start reading through "dataSource", until we see a SCR time code:
  parentDemux.lastSeenSCR().isValid = False;
  UsageEnvironment& env = dataSource->envir(); // alias
  DummySink sink(parentDemux, returnFirstSeenCode);
  sink.startPlaying(*dataSource,
                    (MediaSink::afterPlayingFunc*)afterPlayingDummySink, &sink);
  env.taskScheduler().doEventLoop(&sink.watchVariable);

  timeCode = computeSCRTimeCode(parentDemux.lastSeenSCR());
  return parentDemux.lastSeenSCR().isValid;
}

static float MPEG1or2ProgramStreamFileDuration	(	UsageEnvironment &	env,
		char const *	fileName,
		unsigned &	fileSize
	)			[static]

Definition at line 117 of file MPEG1or2FileServerDemux.cpp.

References Medium::close(), MPEG1or2Demux::createNew(), ByteStreamFileSource::createNew(), duration, env, False, ByteStreamFileSource::fileSize(), MPEG1or2Demux::flushInput(), getMPEG1or2TimeCode(), MPEG1or2Demux::newRawPESStream(), NULL, ByteStreamFileSource::seekToByteAbsolute(), and True.

Referenced by MPEG1or2FileServerDemux::MPEG1or2FileServerDemux().

                                                                   {
  FramedSource* dataSource = NULL;
  float duration = 0.0; // until we learn otherwise
  fileSize = 0; // ditto

  do {
    // Open the input file as a 'byte-stream file source':
    ByteStreamFileSource* fileSource = ByteStreamFileSource::createNew(env, fileName);
    if (fileSource == NULL) break;
    dataSource = fileSource;

    fileSize = (unsigned)(fileSource->fileSize());
    if (fileSize == 0) break;

    // Create a MPEG demultiplexor that reads from that source.
    MPEG1or2Demux* baseDemux = MPEG1or2Demux::createNew(env, dataSource, True);
    if (baseDemux == NULL) break;

    // Create, from this, a source that returns raw PES packets:
    dataSource = baseDemux->newRawPESStream();

    // Read the first time code from the file:
    float firstTimeCode;
    if (!getMPEG1or2TimeCode(dataSource, *baseDemux, True, firstTimeCode)) break;

    // Then, read the last time code from the file.
    // (Before doing this, flush the demux's input buffers,
    //  and seek towards the end of the file, for efficiency.)
    baseDemux->flushInput();
    unsigned const startByteFromEnd = 100000;
    unsigned newFilePosition
      = fileSize < startByteFromEnd ? 0 : fileSize - startByteFromEnd;
    if (newFilePosition > 0) fileSource->seekToByteAbsolute(newFilePosition);

    float lastTimeCode;
    if (!getMPEG1or2TimeCode(dataSource, *baseDemux, False, lastTimeCode)) break;

    // Take the difference between these time codes as being the file duration:
    float timeCodeDiff = lastTimeCode - firstTimeCode;
    if (timeCodeDiff < 0) break;
    duration = timeCodeDiff;
  } while (0);

  Medium::close(dataSource);
  return duration;
}

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