@@ -248,6 +313,14 @@ private:
scanPicture
};
int state;
+ void HandleStartCode(const uchar *const Data, cRingBufferLinear *const ResultBuffer, const uchar *&Payload, const uchar StreamID, const ePesHeader MpegLevel);
+ inline bool ScanDataForStartCodeSlow(const uchar *const Data);
+ inline bool ScanDataForStartCodeFast(const uchar *&Data, const uchar *Limit);
+ inline bool ScanDataForStartCode(const uchar *&Data, int &Done, int &Todo);
+ inline void AdjustCounters(const int Delta, int &Done, int &Todo);
+ inline bool ScanForEndOfPictureSlow(const uchar *&Data);
+ inline bool ScanForEndOfPictureFast(const uchar *&Data, const uchar *Limit);
+ inline bool ScanForEndOfPicture(const uchar *&Data, const uchar *Limit);
public:
cVideoRepacker(void);
virtual void Reset(void);
@@ -267,6 +340,162 @@ void cVideoRepacker::Reset(void)
state = syncing;
}
+void cVideoRepacker::HandleStartCode(const uchar *const Data, cRingBufferLinear *const ResultBuffer, const uchar *&Payload, const uchar StreamID, const ePesHeader MpegLevel)
+{
+ // synchronisation is detected some bytes after frame start.
+ const int SkippedBytesLimit = 4;
+
+ // which kind of start code have we got?
+ switch (*Data) {
+ case 0xB9 ... 0xFF: // system start codes
+ LOG("cVideoRepacker: found system start code: stream seems to be scrambled or not demultiplexed");
+ break;
+ case 0xB0 ... 0xB1: // reserved start codes
+ case 0xB6:
+ LOG("cVideoRepacker: found reserved start code: stream seems to be scrambled");
+ break;
+ case 0xB4: // sequence error code
+ LOG("cVideoRepacker: found sequence error code: stream seems to be damaged");
+ case 0xB2: // user data start code
+ case 0xB5: // extension start code
+ break;
+ case 0xB7: // sequence end code
+ case 0xB3: // sequence header code
+ case 0xB8: // group start code
+ case 0x00: // picture start code
+ if (state == scanPicture) {
+ // the above start codes indicate that the current picture is done. So
+ // push out the packet to start a new packet for the next picuture. If
+ // the byte count get's negative then the current buffer ends in a
+ // partitial start code that must be stripped off, as it shall be put
+ // in the next packet.
+ PushOutPacket(ResultBuffer, Payload, Data - 3 - Payload);
+ // go on with syncing to the next picture
+ state = syncing;
+ }
+ if (state == syncing) {
+ if (initiallySyncing) // omit report for the typical initial case
+ initiallySyncing = false;
+ else if (skippedBytes > SkippedBytesLimit) // report that syncing dropped some bytes
+ LOG("cVideoRepacker: skipped %d bytes to sync on next picture", skippedBytes - SkippedBytesLimit);
+ skippedBytes = 0;
+ // if there is a PES header available, then use it ...
+ if (pesHeaderBackupLen > 0) {
+ // ISO 13818-1 says:
+ // In the case of video, if a PTS is present in a PES packet header
+ // it shall refer to the access unit containing the first picture start
+ // code that commences in this PES packet. A picture start code commences
+ // in PES packet if the first byte of the picture start code is present
+ // in the PES packet.
+ memcpy(pesHeader, pesHeaderBackup, pesHeaderBackupLen);
+ pesHeaderLen = pesHeaderBackupLen;
+ pesHeaderBackupLen = 0;
+ }
+ else {
+ // ... otherwise create a continuation PES header
+ pesHeaderLen = 0;
+ pesHeader[pesHeaderLen++] = 0x00;
+ pesHeader[pesHeaderLen++] = 0x00;
+ pesHeader[pesHeaderLen++] = 0x01;
+ pesHeader[pesHeaderLen++] = StreamID; // video stream ID
+ pesHeader[pesHeaderLen++] = 0x00; // length still unknown
+ pesHeader[pesHeaderLen++] = 0x00; // length still unknown
+
+ if (MpegLevel == phMPEG2) {
+ pesHeader[pesHeaderLen++] = 0x80;
+ pesHeader[pesHeaderLen++] = 0x00;
+ pesHeader[pesHeaderLen++] = 0x00;
+ }
+ else
+ pesHeader[pesHeaderLen++] = 0x0F;
+ }
+ // append the first three bytes of the start code
+ pesHeader[pesHeaderLen++] = 0x00;
+ pesHeader[pesHeaderLen++] = 0x00;
+ pesHeader[pesHeaderLen++] = 0x01;
+ // the next packet's payload will begin with the fourth byte of
+ // the start code (= the actual code)
+ Payload = Data;
+ // as there is no length information available, assume the
+ // maximum we can hold in one PES packet
+ packetTodo = maxPacketSize - pesHeaderLen;
+ // go on with finding the picture data
+ state++;
+ }
+ break;
+ case 0x01 ... 0xAF: // slice start codes
+ if (state == findPicture) {
+ // go on with scanning the picture data
+ state++;
+ }
+ break;
+ }
+}
+
+bool cVideoRepacker::ScanDataForStartCodeSlow(const uchar *const Data)
+{
+ scanner <<= 8;
+ bool FoundStartCode = (scanner == 0x00000100);
+ scanner |= *Data;
+ return FoundStartCode;
+}
+
+bool cVideoRepacker::ScanDataForStartCodeFast(const uchar *&Data, const uchar *Limit)
+{
+ Limit--;
+
+ while (Data < Limit && (Data = (const uchar *)memchr(Data, 0x01, Limit - Data))) {
+ if (Data[-2] || Data[-1])
+ Data += 3;
+ else {
+ scanner = 0x00000100 | *++Data;
+ return true;
+ }
+ }
+
+ Data = Limit;
+ unsigned long *Scanner = (unsigned long *)(Data - 3);
+ scanner = ntohl(*Scanner);
+ return false;
+}
+
+bool cVideoRepacker::ScanDataForStartCode(const uchar *&Data, int &Done, int &Todo)
+{
+ const uchar *const DataOrig = Data;
+ const int MinDataSize = 4;
+
+ if (Todo < MinDataSize || (state != syncing && packetTodo < MinDataSize))
+ return ScanDataForStartCodeSlow(Data);
+
+ int Limit = Todo;
+ if (state != syncing && Limit > packetTodo)
+ Limit = packetTodo;
+
+ if (ScanDataForStartCodeSlow(Data))
+ return true;
+
+ if (ScanDataForStartCodeSlow(++Data)) {
+ AdjustCounters(1, Done, Todo);
+ return true;
+ }
+ ++Data;
+
+ bool FoundStartCode = ScanDataForStartCodeFast(Data, DataOrig + Limit);
+ AdjustCounters(Data - DataOrig, Done, Todo);
+ return FoundStartCode;
+}
+
+void cVideoRepacker::AdjustCounters(const int Delta, int &Done, int &Todo)
+{
+ Done += Delta;
+ Todo -= Delta;
+
+ if (state <= syncing)
+ skippedBytes += Delta;
+ else
+ packetTodo -= Delta;
+}
+
void cVideoRepacker::Repack(cRingBufferLinear *ResultBuffer, const uchar *Data, int Count)
{
// synchronisation is detected some bytes after frame start.
@@ -300,98 +529,9 @@ void cVideoRepacker::Repack(cRingBufferL
if (state <= syncing)
skippedBytes++;
// did we reach a start code?
- scanner <<= 8;
- if (scanner != 0x00000100)
- scanner |= *data;
- else {
- scanner |= *data;
-
- // which kind of start code have we got?
- switch (*data) {
- case 0xB9 ... 0xFF: // system start codes
- LOG("cVideoRepacker: found system start code: stream seems to be scrambled or not demultiplexed");
- break;
- case 0xB0 ... 0xB1: // reserved start codes
- case 0xB6:
- LOG("cVideoRepacker: found reserved start code: stream seems to be scrambled");
- break;
- case 0xB4: // sequence error code
- LOG("cVideoRepacker: found sequence error code: stream seems to be damaged");
- case 0xB2: // user data start code
- case 0xB5: // extension start code
- break;
- case 0xB7: // sequence end code
- case 0xB3: // sequence header code
- case 0xB8: // group start code
- case 0x00: // picture start code
- if (state == scanPicture) {
- // the above start codes indicate that the current picture is done. So
- // push out the packet to start a new packet for the next picuture. If
- // the byte count get's negative then the current buffer ends in a
- // partitial start code that must be stripped off, as it shall be put
- // in the next packet.
- PushOutPacket(ResultBuffer, payload, data - 3 - payload);
- // go on with syncing to the next picture
- state = syncing;
- }
- if (state == syncing) {
- if (initiallySyncing) // omit report for the typical initial case
- initiallySyncing = false;
- else if (skippedBytes > SkippedBytesLimit) // report that syncing dropped some bytes
- LOG("cVideoRepacker: skipped %d bytes to sync on next picture", skippedBytes - SkippedBytesLimit);
- skippedBytes = 0;
- // if there is a PES header available, then use it ...
- if (pesHeaderBackupLen > 0) {
- // ISO 13818-1 says:
- // In the case of video, if a PTS is present in a PES packet header
- // it shall refer to the access unit containing the first picture start
- // code that commences in this PES packet. A picture start code commences
- // in PES packet if the first byte of the picture start code is present
- // in the PES packet.
- memcpy(pesHeader, pesHeaderBackup, pesHeaderBackupLen);
- pesHeaderLen = pesHeaderBackupLen;
- pesHeaderBackupLen = 0;
- }
- else {
- // ... otherwise create a continuation PES header
- pesHeaderLen = 0;
- pesHeader[pesHeaderLen++] = 0x00;
- pesHeader[pesHeaderLen++] = 0x00;
- pesHeader[pesHeaderLen++] = 0x01;
- pesHeader[pesHeaderLen++] = Data[3]; // video stream ID
- pesHeader[pesHeaderLen++] = 0x00; // length still unknown
- pesHeader[pesHeaderLen++] = 0x00; // length still unknown
-
- if (mpegLevel == phMPEG2) {
- pesHeader[pesHeaderLen++] = 0x80;
- pesHeader[pesHeaderLen++] = 0x00;
- pesHeader[pesHeaderLen++] = 0x00;
- }
- else
- pesHeader[pesHeaderLen++] = 0x0F;
- }
- // append the first three bytes of the start code
- pesHeader[pesHeaderLen++] = 0x00;
- pesHeader[pesHeaderLen++] = 0x00;
- pesHeader[pesHeaderLen++] = 0x01;
- // the next packet's payload will begin with the fourth byte of
- // the start code (= the actual code)
- payload = data;
- // as there is no length information available, assume the
- // maximum we can hold in one PES packet
- packetTodo = maxPacketSize - pesHeaderLen;
- // go on with finding the picture data
- state++;
- }
- break;
- case 0x01 ... 0xAF: // slice start codes
- if (state == findPicture) {
- // go on with scanning the picture data
- state++;
- }
- break;
- }
- }
+ if (ScanDataForStartCode(data, done, todo))
+ HandleStartCode(data, ResultBuffer, payload, Data[3], mpegLevel);
+ // move on
data++;
done++;
todo--;
@@ -501,6 +641,79 @@ void cVideoRepacker::Repack(cRingBufferL
}
}
+bool cVideoRepacker::ScanForEndOfPictureSlow(const uchar *&Data)
+{
+ localScanner <<= 8;
+ localScanner |= *Data++;
+ // check start codes which follow picture data
+ switch (localScanner) {
+ case 0x00000100: // picture start code
+ case 0x000001B8: // group start code
+ case 0x000001B3: // sequence header code
+ case 0x000001B7: // sequence end code
+ return true;
+ }
+ return false;
+}
+
+bool cVideoRepacker::ScanForEndOfPictureFast(const uchar *&Data, const uchar *Limit)
+{
+ Limit--;
+
+ while (Data < Limit && (Data = (const uchar *)memchr(Data, 0x01, Limit - Data))) {
+ if (Data[-2] || Data[-1])
+ Data += 3;
+ else {
+ localScanner = 0x00000100 | *++Data;
+ // check start codes which follow picture data
+ switch (localScanner) {
+ case 0x00000100: // picture start code
+ case 0x000001B8: // group start code
+ case 0x000001B3: // sequence header code
+ case 0x000001B7: // sequence end code
+ Data++;
+ return true;
+ default:
+ Data += 3;
+ }
+ }
+ }
+
+ Data = Limit + 1;
+ unsigned long *LocalScanner = (unsigned long *)(Data - 4);
+ localScanner = ntohl(*LocalScanner);
+ return false;
+}
+
+bool cVideoRepacker::ScanForEndOfPicture(const uchar *&Data, const uchar *Limit)
+{
+ const uchar *const DataOrig = Data;
+ const int MinDataSize = 4;
+ bool FoundEndOfPicture;
+
+ if (Limit - Data <= MinDataSize) {
+ FoundEndOfPicture = false;
+ while (Data < Limit) {
+ if (ScanForEndOfPictureSlow(Data)) {
+ FoundEndOfPicture = true;
+ break;
+ }
+ }
+ }
+ else {
+ FoundEndOfPicture = true;
+ if (!ScanForEndOfPictureSlow(Data)) {
+ if (!ScanForEndOfPictureSlow(Data)) {
+ if (!ScanForEndOfPictureFast(Data, Limit))
+ FoundEndOfPicture = false;
+ }
+ }
+ }
+
+ localStart += (Data - DataOrig);
+ return FoundEndOfPicture;
+}
+
int cVideoRepacker::BreakAt(const uchar *Data, int Count)
{
if (initiallySyncing)
@@ -522,19 +735,8 @@ int cVideoRepacker::BreakAt(const uchar
const uchar *data = Data + PesPayloadOffset + localStart;
const uchar *limit = Data + Count;
// scan data
- while (data < limit) {
- localStart++;
- localScanner <<= 8;
- localScanner |= *data++;
- // check start codes which follow picture data
- switch (localScanner) {
- case 0x00000100: // picture start code
- case 0x000001B8: // group start code
- case 0x000001B3: // sequence header code
- case 0x000001B7: // sequence end code
- return data - Data;
- }
- }
+ if (ScanForEndOfPicture(data, limit))
+ return data - Data;
}
// just fill up packet and append next start code
return PesPayloadOffset + packetTodo + 4;