bool
mpeg_es_reader_c::read_frame(M2VParser &parser,
mm_io_c &in,
int64_t max_size) {
auto af_buffer = memory_c::alloc(READ_SIZE);
auto buffer = af_buffer->get_buffer();
int bytes_probed = 0;
while (true) {
auto state = parser.GetState();
if (MPV_PARSER_STATE_FRAME == state)
return true;
if ((MPV_PARSER_STATE_EOS == state) || (MPV_PARSER_STATE_ERROR == state))
return false;
assert(MPV_PARSER_STATE_NEED_DATA == state);
if ((max_size != -1) && (bytes_probed > max_size))
return false;
int bytes_read = in.read(buffer, std::min<int>(parser.GetFreeBufferSpace(), READ_SIZE));
if (!bytes_read)
return false;
bytes_probed += bytes_read;
parser.WriteData(buffer, bytes_read);
parser.SetEOS();
}
}
void
mpeg_es_reader_c::read_headers() {
try {
M2VParser parser;
// Let's find the first frame. We need its information like
// resolution, MPEG version etc.
parser.SetProbeMode();
if (!read_frame(parser, *m_in, 1024 * 1024))
throw mtx::input::header_parsing_x();
m_in->setFilePointer(0);
MPEG2SequenceHeader seq_hdr = parser.GetSequenceHeader();
version = parser.GetMPEGVersion();
interlaced = !seq_hdr.progressiveSequence;
width = seq_hdr.width;
height = seq_hdr.height;
frame_rate = seq_hdr.progressiveSequence ? seq_hdr.frameOrFieldRate : seq_hdr.frameOrFieldRate * 2.0f;
aspect_ratio = seq_hdr.aspectRatio;
if ((0 >= aspect_ratio) || (1 == aspect_ratio))
dwidth = width;
else
dwidth = (int)(height * aspect_ratio);
dheight = height;
MPEGChunk *raw_seq_hdr = parser.GetRealSequenceHeader();
if (raw_seq_hdr) {
m_ti.m_private_data = (unsigned char *)safememdup(raw_seq_hdr->GetPointer(), raw_seq_hdr->GetSize());
m_ti.m_private_size = raw_seq_hdr->GetSize();
}
mxverb(2, boost::format("mpeg_es_reader: version %1% width %2% height %3% FPS %4% AR %5%\n") % version % width % height % frame_rate % aspect_ratio);
} catch (mtx::mm_io::exception &) {
throw mtx::input::open_x();
}
show_demuxer_info();
}
bool
mpeg_es_reader_c::read_frame(M2VParser &parser,
mm_io_c &in,
int64_t max_size) {
int bytes_probed;
bytes_probed = 0;
while (true) {
int state;
state = parser.GetState();
if (MPV_PARSER_STATE_NEED_DATA == state) {
if ((max_size != -1) && (bytes_probed > max_size))
return false;
int bytes_to_read = (parser.GetFreeBufferSpace() < READ_SIZE) ? parser.GetFreeBufferSpace() : READ_SIZE;
unsigned char *buffer = new unsigned char[bytes_to_read];
int bytes_read = in.read(buffer, bytes_to_read);
if (0 == bytes_read) {
delete [] buffer;
break;
}
bytes_probed += bytes_read;
parser.WriteData(buffer, bytes_read);
parser.SetEOS();
delete [] buffer;
} else if (MPV_PARSER_STATE_FRAME == state)
return true;
else if ((MPV_PARSER_STATE_EOS == state) || (MPV_PARSER_STATE_ERROR == state))
return false;
}
return false;
}
int
mpeg_es_reader_c::probe_file(mm_io_c *in,
uint64_t size) {
if (PROBESIZE > size)
return 0;
try {
memory_cptr af_buf = memory_c::alloc(READ_SIZE);
unsigned char *buf = af_buf->get_buffer();
in->setFilePointer(0, seek_beginning);
int num_read = in->read(buf, READ_SIZE);
if (4 > num_read)
return 0;
in->setFilePointer(0, seek_beginning);
// MPEG TS starts with 0x47.
if (0x47 == buf[0])
return 0;
// MPEG PS starts with 0x000001ba.
uint32_t value = get_uint32_be(buf);
if (MPEGVIDEO_PACKET_START_CODE == value)
return 0;
// Due to type detection woes mkvmerge requires
// the stream to start with a MPEG start code.
if (!mpeg_is_start_code(value))
return 0;
bool gop_start_code_found = false;
bool sequence_start_code_found = false;
bool ext_start_code_found = false;
bool picture_start_code_found = false;
bool slice_start_code_found = false;
bool ok = false;
// Let's look for a MPEG ES start code inside the first 1 MB.
int i;
for (i = 4; i < num_read - 1; i++) {
if (mpeg_is_start_code(value)) {
mxverb(3, boost::format("mpeg_es_detection: start code found; fourth byte: 0x%|1$02x|\n") % (value & 0xff));
if (MPEGVIDEO_SEQUENCE_HEADER_START_CODE == value)
sequence_start_code_found = true;
else if (MPEGVIDEO_PICTURE_START_CODE == value)
picture_start_code_found = true;
else if (MPEGVIDEO_GROUP_OF_PICTURES_START_CODE == value)
gop_start_code_found = true;
else if (MPEGVIDEO_EXT_START_CODE == value)
gop_start_code_found = true;
else if ((MPEGVIDEO_FIRST_SLICE_START_CODE >= value) && (MPEGVIDEO_LAST_SLICE_START_CODE <= value))
slice_start_code_found = true;
ok = sequence_start_code_found && picture_start_code_found && (gop_start_code_found || ext_start_code_found || slice_start_code_found);
if (ok)
break;
}
value <<= 8;
value |= buf[i];
}
mxverb(3,
boost::format("mpeg_es_detection: sequence %1% picture %2% gop %3% ext %4% slice %5%\n")
% sequence_start_code_found % picture_start_code_found % gop_start_code_found % ext_start_code_found % slice_start_code_found);
if (!ok)
return 0;
// Let's try to read one frame.
M2VParser parser;
parser.SetProbeMode();
if (!read_frame(parser, *in, READ_SIZE))
return 0;
} catch (...) {
return 0;
}
return 1;
}
