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vdr/remux.c

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/*
* remux.c: A streaming MPEG2 remultiplexer
*
* See the main source file 'vdr.c' for copyright information and
* how to reach the author.
*
* The parts of this code that implement cTS2PES have been taken from
* the Linux DVB driver's 'tuxplayer' example and were rewritten to suit
* VDR's needs.
*
* $Id: remux.c 1.3 2001/06/02 15:39:16 kls Exp $
*/
/* The calling interface of the 'cRemux::Process()' function is defined
as follows:
'Data' points to a chunk of data that consists of 'Count' bytes.
The 'Process' function shall try to remultiplex as much of the
data as possible and return a pointer to the resulting buffer.
That buffer typically is different from the incoming 'Data',
but in the simplest case (when 'Process' does nothing) might
as well point to the original 'Data'. When returning, 'Count'
shall be set to the number of bytes that have been processed
(i.e. have been taken from 'Data'), while 'Result' indicates
how many bytes the returned buffer contains. 'PictureType' shall
be set to NO_PICTURE if the returned data does not start a new
picture, or one of I_FRAME, P_FRAME or B_FRAME if a new picture
starting point has been found. This also means that the returned
data buffer may contain at most one entire video frame, because
the next frame must be returned with its own value for 'PictureType'.
'Process' shall do it's best to keep the latency time as short
as possible in order to allow a quick start of VDR's "Transfer
mode" (displaying the signal of one DVB card on another card).
In order to do that, this function may decide to first pass
through the incoming data (almost) unprocessed, and make
actual processing kick in after a few seconds (if that is at
all possible for the algorithm). This may result in a non-
optimal stream at the beginning, which won't matter for normal
recordings but may make switching through encrypted channels
in "Transfer mode" faster.
In the resulting data stream, a new packet shall always be started
when a frame border is encountered. VDR needs this in order to
be able to detect and store the frame indexes, and to easily
display single frames in fast forward/back mode. The very first
data block returned shall be the starting point of an I_FRAME.
Everything before that shall be silently dropped.
If the incoming data is not enough to do remultiplexing, a value
of NULL shall be returned ('Result' has no meaning then). This
will tell the caller to wait for more data to be presented in
the next call. If NULL is returned and 'Count' is not 0, the
caller shall remove 'Count' bytes from the beginning of 'Data'
before the next call. This is the way 'Process' indicates that
it must skip that data.
Any data that is not used during this call will appear at the
beginning of the incoming 'Data' buffer at the next call, plus
any new data that has become available.
It is guaranteed that the caller will completely process any
returned data before the next call to 'Process'. That way, 'Process'
can dynamically allocate its return buffer and be sure the caller
doesn't keep any pointers into that buffer.
*/
#include "remux.h"
#include "thread.h"
#include "tools.h"
// --- cTS2PES ---------------------------------------------------------------
#include <netinet/in.h>
//XXX TODO: these should really be available in some driver header file!
#define PROG_STREAM_MAP 0xBC
#ifndef PRIVATE_STREAM1
#define PRIVATE_STREAM1 0xBD
#endif
#define PADDING_STREAM 0xBE
#ifndef PRIVATE_STREAM2
#define PRIVATE_STREAM2 0xBF
#endif
#define AUDIO_STREAM_S 0xC0
#define AUDIO_STREAM_E 0xDF
#define VIDEO_STREAM_S 0xE0
#define VIDEO_STREAM_E 0xEF
#define ECM_STREAM 0xF0
#define EMM_STREAM 0xF1
#define DSM_CC_STREAM 0xF2
#define ISO13522_STREAM 0xF3
#define PROG_STREAM_DIR 0xFF
//pts_dts flags
#define PTS_ONLY 0x80
#define TS_SIZE 188
#define PAY_START 0x40
#define PID_MASK_HI 0x1F
//flags
#define ADAPT_FIELD 0x20
//XXX TODO
#define MAX_PLENGTH 0xFFFF
#define MMAX_PLENGTH (4*MAX_PLENGTH)
#define IPACKS 2048
class cTS2PES {
private:
int size;
int found;
int count;
uint8_t *buf;
uint8_t cid;
int plength;
uint8_t plen[2];
uint8_t flag1;
uint8_t flag2;
uint8_t hlength;
int mpeg;
uint8_t check;
int which;
bool done;
uint8_t *resultBuffer;
int *resultCount;
static uint8_t headr[];
void store(uint8_t *Data, int Count);
void reset_ipack(void);
void send_ipack(void);
void write_ipack(const uint8_t *Data, int Count);
void instant_repack(const uint8_t *Buf, int Count);
public:
cTS2PES(uint8_t *ResultBuffer, int *ResultCount, int Size);
~cTS2PES();
void ts_to_pes(const uint8_t *Buf); // don't need count (=188)
void Clear(void);
};
uint8_t cTS2PES::headr[] = { 0x00, 0x00, 0x01 };
cTS2PES::cTS2PES(uint8_t *ResultBuffer, int *ResultCount, int Size)
{
resultBuffer = ResultBuffer;
resultCount = ResultCount;
size = Size;
if (!(buf = new uint8_t[size]))
esyslog(LOG_ERR, "Not enough memory for ts_transform");
reset_ipack();
}
cTS2PES::~cTS2PES()
{
delete buf;
}
void cTS2PES::Clear(void)
{
reset_ipack();
}
void cTS2PES::store(uint8_t *Data, int Count)
{
//XXX overflow check???
memcpy(resultBuffer + *resultCount, Data, Count);
*resultCount += Count;
}
void cTS2PES::reset_ipack(void)
{
found = 0;
cid = 0;
plength = 0;
flag1 = 0;
flag2 = 0;
hlength = 0;
mpeg = 0;
check = 0;
which = 0;
done = false;
count = 0;
}
void cTS2PES::send_ipack(void)
{
if (count < 10)
return;
buf[3] = cid;
buf[4] = (uint8_t)(((count - 6) & 0xFF00) >> 8);
buf[5] = (uint8_t)((count - 6) & 0x00FF);
store(buf, count);
switch (mpeg) {
case 2:
buf[6] = 0x80;
buf[7] = 0x00;
buf[8] = 0x00;
count = 9;
break;
case 1:
buf[6] = 0x0F;
count = 7;
break;
}
}
void cTS2PES::write_ipack(const uint8_t *Data, int Count)
{
if (count < 6) {
memcpy(buf, headr, 3);
count = 6;
}
if (count + Count < size) {
memcpy(buf + count, Data, Count);
count += Count;
}
else {
int rest = size - count;
memcpy(buf + count, Data, rest);
count += rest;
send_ipack();
if (Count - rest > 0)
write_ipack(Data + rest, Count - rest);
}
}
void cTS2PES::instant_repack(const uint8_t *Buf, int Count)
{
int c = 0;
while (c < Count && (mpeg == 0 || (mpeg == 1 && found < 7) || (mpeg == 2 && found < 9)) && (found < 5 || !done)) {
switch (found ) {
case 0:
case 1:
if (Buf[c] == 0x00)
found++;
else
found = 0;
c++;
break;
case 2:
if (Buf[c] == 0x01)
found++;
else if (Buf[c] != 0)
found = 0;
c++;
break;
case 3:
cid = 0;
switch (Buf[c]) {
case PROG_STREAM_MAP:
case PRIVATE_STREAM2:
case PROG_STREAM_DIR:
case ECM_STREAM :
case EMM_STREAM :
case PADDING_STREAM :
case DSM_CC_STREAM :
case ISO13522_STREAM:
done = true;
case PRIVATE_STREAM1:
case VIDEO_STREAM_S ... VIDEO_STREAM_E:
case AUDIO_STREAM_S ... AUDIO_STREAM_E:
found++;
cid = Buf[c++];
break;
default:
found = 0;
break;
}
break;
case 4:
if (Count - c > 1) {
unsigned short *pl = (unsigned short *)(Buf + c);
plength = ntohs(*pl);
c += 2;
found += 2;
}
else {
plen[0] = Buf[c];
found++;
return;
}
break;
case 5: {
plen[1] = Buf[c++];
unsigned short *pl = (unsigned short *)plen;
plength = ntohs(*pl);
found++;
}
break;
case 6:
if (!done) {
flag1 = Buf[c++];
found++;
if ((flag1 & 0xC0) == 0x80 )
mpeg = 2;
else {
esyslog(LOG_INFO, "ERROR: can't record MPEG1!");
hlength = 0;
which = 0;
mpeg = 1;
flag2 = 0;
}
}
break;
case 7:
if (!done && mpeg == 2) {
flag2 = Buf[c++];
found++;
}
break;
case 8:
if (!done && mpeg == 2) {
hlength = Buf[c++];
found++;
}
break;
default:
break;
}
}
if (!plength)
plength = MMAX_PLENGTH - 6;
if (done || ((mpeg == 2 && found >= 9) || (mpeg == 1 && found >= 7))) {
switch (cid) {
case AUDIO_STREAM_S ... AUDIO_STREAM_E:
case VIDEO_STREAM_S ... VIDEO_STREAM_E:
case PRIVATE_STREAM1:
if (mpeg == 2 && found == 9) {
write_ipack(&flag1, 1);
write_ipack(&flag2, 1);
write_ipack(&hlength, 1);
}
if (mpeg == 2 && (flag2 & PTS_ONLY) && found < 14) {
while (c < Count && found < 14) {
write_ipack(Buf + c, 1);
c++;
found++;
}
if (c == Count)
return;
}
while (c < Count && found < plength + 6) {
int l = Count - c;
if (l + found > plength + 6)
l = plength + 6 - found;
write_ipack(Buf + c, l);
found += l;
c += l;
}
break;
}
if (done) {
if (found + Count - c < plength + 6) {
found += Count - c;
c = Count;
}
else {
c += plength + 6 - found;
found = plength + 6;
}
}
if (plength && found == plength + 6) {
send_ipack();
reset_ipack();
if (c < Count)
instant_repack(Buf + c, Count - c);
}
}
return;
}
void cTS2PES::ts_to_pes(const uint8_t *Buf) // don't need count (=188)
{
if (!Buf)
return;
if (Buf[1] & PAY_START) {
if (plength == MMAX_PLENGTH - 6 && found > 6) {
plength = found - 6;
found = 0;
send_ipack();
reset_ipack();
}
}
uint8_t off = 0;
if (Buf[3] & ADAPT_FIELD) { // adaptation field?
off = Buf[4] + 1;
if (off + 4 > 187)
return;
}
instant_repack(Buf + 4 + off, TS_SIZE - 4 - off);
}
// --- cRemux ----------------------------------------------------------------
cRemux::cRemux(dvb_pid_t VPid, dvb_pid_t APid, bool ExitOnFailure)
{
vPid = VPid;
aPid = APid;
exitOnFailure = ExitOnFailure;
synced = false;
skipped = 0;
resultCount = resultDelivered = 0;
vTS2PES = new cTS2PES(resultBuffer, &resultCount, IPACKS);
aTS2PES = new cTS2PES(resultBuffer, &resultCount, IPACKS);
}
cRemux::~cRemux()
{
delete vTS2PES;
delete aTS2PES;
}
int cRemux::GetPid(const uchar *Data)
{
return (((uint16_t)Data[0] & PID_MASK_HI) << 8) | (Data[1] & 0xFF);
}
int cRemux::GetPacketLength(const uchar *Data, int Count, int Offset)
{
// Returns the entire length of the packet starting at offset, or -1 in case of error.
return (Offset + 5 < Count) ? (Data[Offset + 4] << 8) + Data[Offset + 5] + 6 : -1;
}
int cRemux::ScanVideoPacket(const uchar *Data, int Count, int Offset, uchar &PictureType)
{
// Scans the video packet starting at Offset and returns its length.
// If the return value is -1 the packet was not completely in the buffer.
int Length = GetPacketLength(Data, Count, Offset);
if (Length > 0 && Offset + Length <= Count) {
int i = Offset + 8; // the minimum length of the video packet header
i += Data[i] + 1; // possible additional header bytes
for (; i < Offset + Length; i++) {
if (Data[i] == 0 && Data[i + 1] == 0 && Data[i + 2] == 1) {
switch (Data[i + 3]) {
case SC_PICTURE: PictureType = (Data[i + 5] >> 3) & 0x07;
return Length;
}
}
}
PictureType = NO_PICTURE;
return Length;
}
return -1;
}
void cRemux::SetAudioPid(int APid)
{
aPid = APid;
vTS2PES->Clear();
aTS2PES->Clear();
resultCount = resultDelivered = 0;
}
const uchar *cRemux::Process(const uchar *Data, int &Count, int &Result, uchar *PictureType)
{
uchar dummyPictureType;
if (!PictureType)
PictureType = &dummyPictureType;
/*XXX
// test recording the raw TS:
Result = Count;
*PictureType = I_FRAME;
return Data;
XXX*/
// Remove any previously delivered data from the result buffer:
if (resultDelivered) {
if (resultDelivered < resultCount)
memmove(resultBuffer, resultBuffer + resultDelivered, resultCount - resultDelivered);
resultCount -= resultDelivered;
resultDelivered = 0;
}
// Convert incoming TS data into multiplexed PES:
int used = 0;
for (int i = 0; i < Count; i += TS_SIZE) {
if (Count - i < TS_SIZE)
break;
dvb_pid_t pid = GetPid(Data + i + 1);
if (Data[i + 3] & 0x10) { // got payload
if (pid == vPid)
vTS2PES->ts_to_pes(Data + i);
else if (pid == aPid)
aTS2PES->ts_to_pes(Data + i);
}
used += TS_SIZE;
if (resultCount > (int)sizeof(resultBuffer) / 2)
break;
}
Count = used;
/*XXX
// test recording without determining the real frame borders:
*PictureType = I_FRAME;
Result = resultDelivered = resultCount;
return Result ? resultBuffer : NULL;
XXX*/
// Check if we're getting anywhere here:
if (!synced && skipped >= 0) {
if (skipped > 1024*1024) {
esyslog(LOG_ERR, "ERROR: no useful data seen within %d byte of video stream", skipped);
skipped = -1;
if (exitOnFailure)
cThread::EmergencyExit(true);
}
else
skipped += Count;
}
// Check for frame borders:
*PictureType = NO_PICTURE;
if (resultCount >= MINVIDEODATA) {
for (int i = 0; i < resultCount; i++) {
if (resultBuffer[i] == 0 && resultBuffer[i + 1] == 0 && resultBuffer[i + 2] == 1) {
switch (resultBuffer[i + 3]) {
case SC_VIDEO:
{
uchar pt = NO_PICTURE;
int l = ScanVideoPacket(resultBuffer, resultCount, i, pt);
if (l < 0)
return NULL; // no useful data found, wait for more
if (pt != NO_PICTURE) {
if (pt < I_FRAME || B_FRAME < pt) {
esyslog(LOG_ERR, "ERROR: unknown picture type '%d'", pt);
}
else if (!synced) {
if (pt == I_FRAME) {
resultDelivered = i; // will drop everything before this position
synced = true;
}
else {
resultDelivered = i + l; // will drop everything before and including this packet
return NULL;
}
}
}
if (synced) {
*PictureType = pt;
Result = l;
const uchar *p = resultBuffer + resultDelivered;
resultDelivered += l;
return p;
}
else {
resultDelivered = i + l; // will drop everything before and including this packet
return NULL;
}
}
break;
case SC_AUDIO:
{
int l = GetPacketLength(resultBuffer, resultCount, i);
if (l < 0)
return NULL; // no useful data found, wait for more
if (synced) {
Result = l;
const uchar *p = resultBuffer + resultDelivered;
resultDelivered += l;
return p;
}
else {
resultDelivered = i + l; // will drop everything before and including this packet
return NULL;
}
}
break;
}
}
}
}
return NULL; // no useful data found, wait for more
}
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