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/**********
This library is free software; you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License as published by the
Free Software Foundation; either version 2.1 of the License, or (at your
option) any later version. (See <http://www.gnu.org/copyleft/lesser.html>.)
This library is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for
more details.
You should have received a copy of the GNU Lesser General Public License
along with this library; if not, write to the Free Software Foundation, Inc.,
59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
**********/
// "liveMedia"
// Copyright (c) 1996-2005 Live Networks, Inc. All rights reserved.
// A filter that breaks up an MPEG video elementary stream into
// headers and frames
// Implementation
#include "MPEGVideoStreamParser.hh"
#include <GroupsockHelper.hh>
////////// TimeCode implementation //////////
TimeCode::TimeCode()
: days(0), hours(0), minutes(0), seconds(0), pictures(0) {
}
TimeCode::~TimeCode() {
}
int TimeCode::operator==(TimeCode const& arg2) {
return pictures == arg2.pictures && seconds == arg2.seconds
&& minutes == arg2.minutes && hours == arg2.hours && days == arg2.days;
}
////////// MPEGVideoStreamFramer implementation //////////
MPEGVideoStreamFramer::MPEGVideoStreamFramer(UsageEnvironment& env,
FramedSource* inputSource)
: FramedFilter(env, inputSource),
fFrameRate(0.0) /* until we learn otherwise */,
fParser(NULL) {
reset();
}
MPEGVideoStreamFramer::~MPEGVideoStreamFramer() {
delete fParser;
}
void MPEGVideoStreamFramer::flushInput() {
reset();
if (fParser != NULL) fParser->flushInput();
}
void MPEGVideoStreamFramer::reset() {
fPictureCount = 0;
fPictureEndMarker = False;
fPicturesAdjustment = 0;
fPictureTimeBase = 0.0;
fTcSecsBase = 0;
fHaveSeenFirstTimeCode = False;
// Use the current wallclock time as the base 'presentation time':
gettimeofday(&fPresentationTimeBase, NULL);
}
#ifdef DEBUG
static struct timeval firstPT;
#endif
void MPEGVideoStreamFramer
::computePresentationTime(unsigned numAdditionalPictures) {
// Computes "fPresentationTime" from the most recent GOP's
// time_code, along with the "numAdditionalPictures" parameter:
TimeCode& tc = fCurGOPTimeCode;
unsigned tcSecs
= (((tc.days*24)+tc.hours)*60+tc.minutes)*60+tc.seconds - fTcSecsBase;
double pictureTime = fFrameRate == 0.0 ? 0.0
: (tc.pictures + fPicturesAdjustment + numAdditionalPictures)/fFrameRate;
while (pictureTime < fPictureTimeBase) { // "if" should be enough, but just in case
if (tcSecs > 0) tcSecs -= 1;
pictureTime += 1.0;
}
pictureTime -= fPictureTimeBase;
if (pictureTime < 0.0) pictureTime = 0.0; // sanity check
unsigned pictureSeconds = (unsigned)pictureTime;
double pictureFractionOfSecond = pictureTime - (double)pictureSeconds;
fPresentationTime = fPresentationTimeBase;
fPresentationTime.tv_sec += tcSecs + pictureSeconds;
fPresentationTime.tv_usec += (long)(pictureFractionOfSecond*1000000.0);
if (fPresentationTime.tv_usec >= 1000000) {
fPresentationTime.tv_usec -= 1000000;
++fPresentationTime.tv_sec;
}
#ifdef DEBUG
if (firstPT.tv_sec == 0 && firstPT.tv_usec == 0) firstPT = fPresentationTime;
struct timeval diffPT;
diffPT.tv_sec = fPresentationTime.tv_sec - firstPT.tv_sec;
diffPT.tv_usec = fPresentationTime.tv_usec - firstPT.tv_usec;
if (fPresentationTime.tv_usec < firstPT.tv_usec) {
--diffPT.tv_sec;
diffPT.tv_usec += 1000000;
}
fprintf(stderr, "MPEGVideoStreamFramer::computePresentationTime(%d) -> %lu.%06ld [%lu.%06ld]\n", numAdditionalPictures, fPresentationTime.tv_sec, fPresentationTime.tv_usec, diffPT.tv_sec, diffPT.tv_usec);
#endif
}
void MPEGVideoStreamFramer
::setTimeCode(unsigned hours, unsigned minutes, unsigned seconds,
unsigned pictures, unsigned picturesSinceLastGOP) {
TimeCode& tc = fCurGOPTimeCode; // abbrev
unsigned days = tc.days;
if (hours < tc.hours) {
// Assume that the 'day' has wrapped around:
++days;
}
tc.days = days;
tc.hours = hours;
tc.minutes = minutes;
tc.seconds = seconds;
tc.pictures = pictures;
if (!fHaveSeenFirstTimeCode) {
fPictureTimeBase = fFrameRate == 0.0 ? 0.0 : tc.pictures/fFrameRate;
fTcSecsBase = (((tc.days*24)+tc.hours)*60+tc.minutes)*60+tc.seconds;
fHaveSeenFirstTimeCode = True;
} else if (fCurGOPTimeCode == fPrevGOPTimeCode) {
// The time code has not changed since last time. Adjust for this:
fPicturesAdjustment += picturesSinceLastGOP;
} else {
// Normal case: The time code changed since last time.
fPrevGOPTimeCode = tc;
fPicturesAdjustment = 0;
}
}
void MPEGVideoStreamFramer::doGetNextFrame() {
fParser->registerReadInterest(fTo, fMaxSize);
continueReadProcessing();
}
void MPEGVideoStreamFramer
::continueReadProcessing(void* clientData,
unsigned char* /*ptr*/, unsigned /*size*/,
struct timeval /*presentationTime*/) {
MPEGVideoStreamFramer* framer = (MPEGVideoStreamFramer*)clientData;
framer->continueReadProcessing();
}
void MPEGVideoStreamFramer::continueReadProcessing() {
unsigned acquiredFrameSize = fParser->parse();
if (acquiredFrameSize > 0) {
// We were able to acquire a frame from the input.
// It has already been copied to the reader's space.
fFrameSize = acquiredFrameSize;
fNumTruncatedBytes = fParser->numTruncatedBytes();
// "fPresentationTime" should have already been computed.
// Compute "fDurationInMicroseconds" now:
fDurationInMicroseconds
= (fFrameRate == 0.0 || ((int)fPictureCount) < 0) ? 0
: (unsigned)((fPictureCount*1000000)/fFrameRate);
#ifdef DEBUG
fprintf(stderr, "fDurationInMicroseconds: %d ((%d*1000000)/%f)\n", fDurationInMicroseconds, fPictureCount, fFrameRate);
#endif
fPictureCount = 0;
// Call our own 'after getting' function. Because we're not a 'leaf'
// source, we can call this directly, without risking infinite recursion.
afterGetting(this);
} else {
// We were unable to parse a complete frame from the input, because:
// - we had to read more data from the source stream, or
// - the source stream has ended.
}
}
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