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Fixed detecting frames in case the Picture Start Code or Access Unit Delimiter extends over TS packet boundaries (cont'd)

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This commit is contained in:
Klaus Schmidinger 2011-06-12 14:06:11 +02:00
parent 098d21117e
commit 72d342ce02
5 changed files with 75 additions and 41 deletions
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3
HISTORY
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@ -6634,6 +6634,9 @@ Video Disk Recorder Revision History
channel is being received with.
- Fixed detecting frames in case the Picture Start Code or Access Unit Delimiter
extends over TS packet boundaries (reported by Johan Andersson).
In order to fix this, the semantics of cFrameDetector had to be changed a little.
See cRecorder::Action() and cIndexFileGenerator::Action() on how to use the new
cFrameDetector::NewPayload() function.
- The frame detector now only starts collecting PTS values after it has seen the
first I-frame, otherwise it might get MaxPtsValues values and stop analyzing
even though the incoming data is still garbage (reported by Derek Kelly).

12
recorder.c
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@ -4,7 +4,7 @@
* See the main source file 'vdr.c' for copyright information and
* how to reach the author.
*
* $Id: recorder.c 2.9 2010/12/27 11:35:46 kls Exp $
* $Id: recorder.c 2.10 2011/06/12 13:35:20 kls Exp $
*/
#include "recorder.h"
@ -31,7 +31,7 @@ cRecorder::cRecorder(const char *FileName, const cChannel *Channel, int Priority
SpinUpDisk(FileName);
ringBuffer = new cRingBufferLinear(RECORDERBUFSIZE, MIN_TS_PACKETS_FOR_FRAME_DETECTOR * TS_SIZE, true, "Recorder");
ringBuffer = new cRingBufferLinear(RECORDERBUFSIZE, TS_SIZE, true, "Recorder");
ringBuffer->SetTimeouts(0, 100);
int Pid = Channel->Vpid();
@ -119,6 +119,8 @@ void cRecorder::Action(void)
time_t t = time(NULL);
bool InfoWritten = false;
bool FirstIframeSeen = false;
int FileNumber = 0;
off_t FrameOffset = -1;
while (Running()) {
int r;
uchar *b = ringBuffer->Get(r);
@ -139,12 +141,16 @@ void cRecorder::Action(void)
}
InfoWritten = true;
}
if (frameDetector->NewPayload()) {
FileNumber = fileName->Number();
FrameOffset = fileSize;
}
if (FirstIframeSeen || frameDetector->IndependentFrame()) {
FirstIframeSeen = true; // start recording with the first I-frame
if (!NextFile())
break;
if (index && frameDetector->NewFrame())
index->Write(frameDetector->IndependentFrame(), fileName->Number(), fileSize);
index->Write(frameDetector->IndependentFrame(), FileNumber, FrameOffset);
if (frameDetector->IndependentFrame()) {
recordFile->Write(patPmtGenerator.GetPat(), TS_SIZE);
fileSize += TS_SIZE;

15
recording.c
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@ -4,7 +4,7 @@
* See the main source file 'vdr.c' for copyright information and
* how to reach the author.
*
* $Id: recording.c 2.30 2011/04/17 13:53:11 kls Exp $
* $Id: recording.c 2.31 2011/06/12 13:04:28 kls Exp $
*/
#include "recording.h"
@ -1403,11 +1403,12 @@ void cIndexFileGenerator::Action(void)
bool Rewind = false;
cFileName FileName(recordingName, false);
cUnbufferedFile *ReplayFile = FileName.Open();
cRingBufferLinear Buffer(IFG_BUFFER_SIZE, MIN_TS_PACKETS_FOR_FRAME_DETECTOR * TS_SIZE);
cRingBufferLinear Buffer(IFG_BUFFER_SIZE, TS_SIZE);
cPatPmtParser PatPmtParser;
cFrameDetector FrameDetector;
cIndexFile IndexFile(recordingName, true);
int BufferChunks = KILOBYTE(1); // no need to read a lot at the beginning when parsing PAT/PMT
int FileNumber = 0;
off_t FileSize = 0;
off_t FrameOffset = -1;
Skins.QueueMessage(mtInfo, tr("Regenerating index file"));
@ -1424,12 +1425,18 @@ void cIndexFileGenerator::Action(void)
if (Data) {
if (FrameDetector.Synced()) {
// Step 3 - generate the index:
if (TsPid(Data) == PATPID)
if (FrameOffset < 0 && TsPid(Data) == PATPID) {
FileNumber = FileName.Number();
FrameOffset = FileSize; // the PAT/PMT is at the beginning of an I-frame
}
int Processed = FrameDetector.Analyze(Data, Length);
if (Processed > 0) {
if (FrameDetector.NewPayload() && FrameOffset < 0) {
FileNumber = FileName.Number();
FrameOffset = FileSize;
}
if (FrameDetector.NewFrame()) {
IndexFile.Write(FrameDetector.IndependentFrame(), FileName.Number(), FrameOffset >= 0 ? FrameOffset : FileSize);
IndexFile.Write(FrameDetector.IndependentFrame(), FileNumber, FrameOffset);
FrameOffset = -1;
}
FileSize += Processed;

67
remux.c
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@ -4,7 +4,7 @@
* See the main source file 'vdr.c' for copyright information and
* how to reach the author.
*
* $Id: remux.c 2.55 2011/06/11 11:35:18 kls Exp $
* $Id: remux.c 2.56 2011/06/12 13:51:59 kls Exp $
*/
#include "remux.h"
@ -781,7 +781,8 @@ cFrameDetector::cFrameDetector(int Pid, int Type)
{
SetPid(Pid, Type);
synced = false;
newFrame = independentFrame = false;
newPayload = newFrame = independentFrame = false;
frameTypeOffset = -1;
numPtsValues = 0;
numFrames = 0;
numIFrames = 0;
@ -808,7 +809,8 @@ void cFrameDetector::SetPid(int Pid, int Type)
void cFrameDetector::Reset(void)
{
newFrame = independentFrame = false;
newPayload = newFrame = independentFrame = false;
frameTypeOffset = -1;
payloadUnitOfFrame = 0;
scanning = false;
scanner = EMPTY_SCANNER;
@ -816,9 +818,8 @@ void cFrameDetector::Reset(void)
int cFrameDetector::Analyze(const uchar *Data, int Length)
{
int SeenPayloadStart = false;
int Processed = 0;
newFrame = independentFrame = false;
newPayload = newFrame = independentFrame = false;
while (Length >= TS_SIZE) {
if (Data[0] != TS_SYNC_BYTE) {
int Skipped = 1;
@ -831,11 +832,8 @@ int cFrameDetector::Analyze(const uchar *Data, int Length)
int Pid = TsPid(Data);
if (Pid == pid) {
if (TsPayloadStart(Data)) {
SeenPayloadStart = true;
if (synced && Processed)
return Processed;
if (Length < MIN_TS_PACKETS_FOR_FRAME_DETECTOR * TS_SIZE)
return Processed; // need more data, in case the frame type is not stored in the first TS packet
return Processed; // flush everything before this new payload
if (framesPerSecond <= 0.0) {
// frame rate unknown, so collect a sequence of PTS values:
if (numPtsValues < MaxPtsValues && numIFrames < 2) { // collect a sequence containing at least two I-frames
@ -900,35 +898,41 @@ int cFrameDetector::Analyze(const uchar *Data, int Length)
if (scanning) {
int PayloadOffset = TsPayloadOffset(Data);
if (TsPayloadStart(Data)) {
if (synced && Processed)
return Processed; // flush everything before this new payload
newPayload = true;
scanner = EMPTY_SCANNER;
PayloadOffset += PesPayloadOffset(Data + PayloadOffset);
if (!framesPerPayloadUnit)
framesPerPayloadUnit = framesInPayloadUnit;
if (DebugFrames && !synced)
dbgframes("/");
}
int PacketsForFrameDetector = MIN_TS_PACKETS_FOR_FRAME_DETECTOR;
for (int i = PayloadOffset; scanning && i < TS_SIZE; i++) {
if (frameTypeOffset < 0) {
scanner <<= 8;
scanner |= Data[i];
if (i == TS_SIZE - 1) { // it was the last byte in this TS packet
if (SeenPayloadStart && --PacketsForFrameDetector > 0) {
Data += TS_SIZE;
Length -= TS_SIZE;
Processed += TS_SIZE;
if (Length < TS_SIZE)
return Processed;
i = TsPayloadOffset(Data) - 1; // one before the first payload byte of the next TS packet
}
}
else
frameTypeOffset += PayloadOffset;
switch (type) {
case 0x01: // MPEG 1 video
case 0x02: // MPEG 2 video
if (scanner == 0x00000100) { // Picture Start Code
if (frameTypeOffset < 0) {
frameTypeOffset = i + 2;
if (frameTypeOffset >= TS_SIZE) { // the byte to check is in the next TS packet
frameTypeOffset -= TS_SIZE;
if (!synced)
dbgframes("%d>", frameTypeOffset);
break;
}
}
scanner = EMPTY_SCANNER;
if (synced && !SeenPayloadStart && Processed)
return Processed; // flush everything before this new frame
newFrame = true;
independentFrame = ((Data[i + 2] >> 3) & 0x07) == 1; // I-Frame
uchar FrameType = (Data[frameTypeOffset] >> 3) & 0x07;
frameTypeOffset = -1;
independentFrame = FrameType == 1; // I-Frame
if (synced) {
if (framesPerPayloadUnit <= 1)
scanning = false;
@ -939,7 +943,7 @@ int cFrameDetector::Analyze(const uchar *Data, int Length)
numIFrames++;
if (numIFrames == 1)
numFrames++;
dbgframes("%d ", (Data[i + 2] >> 3) & 0x07);
dbgframes("%u ", FrameType);
}
if (synced)
return Processed + TS_SIZE; // flag this new frame
@ -947,11 +951,20 @@ int cFrameDetector::Analyze(const uchar *Data, int Length)
break;
case 0x1B: // MPEG 4 video
if (scanner == 0x00000109) { // Access Unit Delimiter
if (frameTypeOffset < 0) {
frameTypeOffset = i + 1;
if (frameTypeOffset >= TS_SIZE) { // the byte to check is in the next TS packet
frameTypeOffset -= TS_SIZE;
if (!synced)
dbgframes("%d>", frameTypeOffset);
break;
}
}
scanner = EMPTY_SCANNER;
if (synced && !SeenPayloadStart && Processed)
return Processed; // flush everything before this new frame
newFrame = true;
independentFrame = Data[i + 1] == 0x10;
uchar FrameType = Data[frameTypeOffset];
frameTypeOffset = -1;
independentFrame = FrameType == 0x10;
if (synced) {
if (framesPerPayloadUnit < 0) {
payloadUnitOfFrame = (payloadUnitOfFrame + 1) % -framesPerPayloadUnit;
@ -969,7 +982,7 @@ int cFrameDetector::Analyze(const uchar *Data, int Length)
numIFrames++;
if (numIFrames == 1)
numFrames++;
dbgframes("%02X ", Data[i + 1]);
dbgframes("%02X ", FrameType);
}
if (synced)
return Processed + TS_SIZE; // flag this new frame

15
remux.h
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@ -4,7 +4,7 @@
* See the main source file 'vdr.c' for copyright information and
* how to reach the author.
*
* $Id: remux.h 2.29 2011/05/21 09:53:54 kls Exp $
* $Id: remux.h 2.30 2011/06/12 12:49:17 kls Exp $
*/
#ifndef __REMUX_H
@ -297,7 +297,7 @@ public:
~cTsToPes();
void PutTs(const uchar *Data, int Length);
///< Puts the payload data of the single TS packet at Data into the converter.
///< Length is always 188.
///< Length is always TS_SIZE.
///< If the given TS packet starts a new PES payload packet, the converter
///< will be automatically reset. Any packets before the first one that starts
///< a new PES payload packet will be ignored.
@ -336,16 +336,16 @@ void PesDump(const char *Name, const u_char *Data, int Length);
// Frame detector:
#define MIN_TS_PACKETS_FOR_FRAME_DETECTOR 2
class cFrameDetector {
private:
enum { MaxPtsValues = 150 };
int pid;
int type;
bool synced;
bool newPayload;
bool newFrame;
bool independentFrame;
int frameTypeOffset;
uint32_t ptsValues[MaxPtsValues]; // 32 bit is enough - we only need the delta
int numPtsValues;
int numFrames;
@ -371,12 +371,17 @@ public:
///< the frame detector for actual work.
int Analyze(const uchar *Data, int Length);
///< Analyzes the TS packets pointed to by Data. Length is the number of
///< bytes Data points to, and must be a multiple of 188.
///< bytes Data points to, and must be a multiple of TS_SIZE.
///< Returns the number of bytes that have been analyzed.
///< If the return value is 0, the data was not sufficient for analyzing and
///< Analyze() needs to be called again with more actual data.
bool Synced(void) { return synced; }
///< Returns true if the frame detector has synced on the data stream.
bool NewPayload(void) { return newPayload; }
///< Returns true if the data given to the last call to Analyze() started a
///< new payload. The caller should remember the current file offset in
///< order to be able to generate an index entry later, when NewFrame()
///< returns true.
bool NewFrame(void) { return newFrame; }
///< Returns true if the data given to the last call to Analyze() started a
///< new frame.