void EbmlComposer::GenerateHeader()
{
// Write the EBML header.
EbmlGlobal ebml;
// The WEbM header default size usually smaller than 1k.
auto buffer = MakeUnique<uint8_t[]>(DEFAULT_HEADER_SIZE +
mCodecPrivateData.Length());
ebml.buf = buffer.get();
ebml.offset = 0;
writeHeader(&ebml);
{
EbmlLoc segEbmlLoc, ebmlLocseg, ebmlLoc;
Ebml_StartSubElement(&ebml, &segEbmlLoc, Segment);
{
Ebml_StartSubElement(&ebml, &ebmlLocseg, SeekHead);
// Todo: We don't know the exact sizes of encoded data and
// ignore this section.
Ebml_EndSubElement(&ebml, &ebmlLocseg);
writeSegmentInformation(&ebml, &ebmlLoc, TIME_CODE_SCALE, 0);
{
EbmlLoc trackLoc;
Ebml_StartSubElement(&ebml, &trackLoc, Tracks);
{
// Video
if (mWidth > 0 && mHeight > 0) {
writeVideoTrack(&ebml, 0x1, 0, "V_VP8",
mWidth, mHeight,
mDisplayWidth, mDisplayHeight, mFrameRate);
}
// Audio
if (mCodecPrivateData.Length() > 0) {
// Extract the pre-skip from mCodecPrivateData
// then convert it to nanoseconds.
// Details in OpusTrackEncoder.cpp.
mCodecDelay =
(uint64_t)LittleEndian::readUint16(mCodecPrivateData.Elements() + 10)
* PR_NSEC_PER_SEC / 48000;
// Fixed 80ms, convert into nanoseconds.
uint64_t seekPreRoll = 80 * PR_NSEC_PER_MSEC;
writeAudioTrack(&ebml, 0x2, 0x0, "A_OPUS", mSampleFreq,
mChannels, mCodecDelay, seekPreRoll,
mCodecPrivateData.Elements(),
mCodecPrivateData.Length());
}
}
Ebml_EndSubElement(&ebml, &trackLoc);
}
}
// The Recording length is unknown and
// ignore write the whole Segment element size
}
MOZ_ASSERT(ebml.offset <= DEFAULT_HEADER_SIZE + mCodecPrivateData.Length(),
"write more data > EBML_BUFFER_SIZE");
auto block = mClusterBuffs.AppendElement();
block->SetLength(ebml.offset);
memcpy(block->Elements(), ebml.buf, ebml.offset);
mFlushState |= FLUSH_METADATA;
}
void EbmlComposer::GenerateHeader()
{
// Write the EBML header.
EbmlGlobal ebml;
// The WEbM header default size usually smaller than 1k.
nsAutoArrayPtr<uint8_t> buffer(new uint8_t[DEFAULT_HEADER_SIZE +
mCodecPrivateData.Length()]);
ebml.buf = buffer.get();
ebml.offset = 0;
writeHeader(&ebml);
{
EbmlLoc segEbmlLoc, ebmlLocseg, ebmlLoc;
Ebml_StartSubElement(&ebml, &segEbmlLoc, Segment);
{
Ebml_StartSubElement(&ebml, &ebmlLocseg, SeekHead);
// Todo: We don't know the exact sizes of encoded data and
// ignore this section.
Ebml_EndSubElement(&ebml, &ebmlLocseg);
writeSegmentInformation(&ebml, &ebmlLoc, TIME_CODE_SCALE, 0);
{
EbmlLoc trackLoc;
Ebml_StartSubElement(&ebml, &trackLoc, Tracks);
{
// Video
if (mWidth > 0 && mHeight > 0) {
writeVideoTrack(&ebml, 0x1, 0, "V_VP8",
mWidth, mHeight,
mDisplayWidth, mDisplayHeight, mFrameRate);
}
// Audio
if (mCodecPrivateData.Length() > 0) {
writeAudioTrack(&ebml, 0x2, 0x0, "A_VORBIS", mSampleFreq,
mChannels, mCodecPrivateData.Elements(),
mCodecPrivateData.Length());
}
}
Ebml_EndSubElement(&ebml, &trackLoc);
}
}
// The Recording length is unknown and
// ignore write the whole Segment element size
}
MOZ_ASSERT(ebml.offset <= DEFAULT_HEADER_SIZE + mCodecPrivateData.Length(),
"write more data > EBML_BUFFER_SIZE");
auto block = mClusterBuffs.AppendElement();
block->SetLength(ebml.offset);
memcpy(block->Elements(), ebml.buf, ebml.offset);
mFlushState |= FLUSH_METADATA;
}
