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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-*/
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "EbmlComposer.h"
#include "mozilla/UniquePtr.h"
#include "mozilla/EndianUtils.h"
#include "libmkv/EbmlIDs.h"
#include "libmkv/EbmlWriter.h"
#include "libmkv/WebMElement.h"
#include "prtime.h"
#include "limits.h"
namespace mozilla {
// Timecode scale in nanoseconds
static const unsigned long TIME_CODE_SCALE = 1000000;
// The WebM header size without audio CodecPrivateData
static const int32_t DEFAULT_HEADER_SIZE = 1024;
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::FinishMetadata()
{
if (mFlushState & FLUSH_METADATA) {
// We don't remove the first element of mClusterBuffs because the
// |mClusterHeaderIndex| may have value.
mClusterCanFlushBuffs.AppendElement()->SwapElements(mClusterBuffs[0]);
mFlushState &= ~FLUSH_METADATA;
}
}
void EbmlComposer::FinishCluster()
{
FinishMetadata();
if (!(mFlushState & FLUSH_CLUSTER)) {
// No completed cluster available.
return;
}
MOZ_ASSERT(mClusterLengthLoc > 0);
EbmlGlobal ebml;
EbmlLoc ebmlLoc;
ebmlLoc.offset = mClusterLengthLoc;
ebml.offset = 0;
for (uint32_t i = mClusterHeaderIndex; i < mClusterBuffs.Length(); i++) {
ebml.offset += mClusterBuffs[i].Length();
}
ebml.buf = mClusterBuffs[mClusterHeaderIndex].Elements();
Ebml_EndSubElement(&ebml, &ebmlLoc);
// Move the mClusterBuffs data from mClusterHeaderIndex that we can skip
// the metadata and the rest P-frames after ContainerWriter::FLUSH_NEEDED.
for (uint32_t i = mClusterHeaderIndex; i < mClusterBuffs.Length(); i++) {
mClusterCanFlushBuffs.AppendElement()->SwapElements(mClusterBuffs[i]);
}
mClusterHeaderIndex = 0;
mClusterLengthLoc = 0;
mClusterBuffs.Clear();
mFlushState &= ~FLUSH_CLUSTER;
}
void
EbmlComposer::WriteSimpleBlock(EncodedFrame* aFrame)
{
EbmlGlobal ebml;
ebml.offset = 0;
auto frameType = aFrame->GetFrameType();
bool flush = false;
bool isVP8IFrame = (frameType == EncodedFrame::FrameType::VP8_I_FRAME);
if (isVP8IFrame) {
FinishCluster();
flush = true;
} else {
// Force it to calculate timecode using signed math via cast
int64_t timeCode = (aFrame->GetTimeStamp() / ((int) PR_USEC_PER_MSEC) - mClusterTimecode) +
(mCodecDelay / PR_NSEC_PER_MSEC);
if (timeCode < SHRT_MIN || timeCode > SHRT_MAX ) {
// We're probably going to overflow (or underflow) the timeCode value later!
FinishCluster();
flush = true;
}
}
auto block = mClusterBuffs.AppendElement();
block->SetLength(aFrame->GetFrameData().Length() + DEFAULT_HEADER_SIZE);
ebml.buf = block->Elements();
if (flush) {
EbmlLoc ebmlLoc;
Ebml_StartSubElement(&ebml, &ebmlLoc, Cluster);
MOZ_ASSERT(mClusterBuffs.Length() > 0);
// current cluster header array index
mClusterHeaderIndex = mClusterBuffs.Length() - 1;
mClusterLengthLoc = ebmlLoc.offset;
// if timeCode didn't under/overflow before, it shouldn't after this
mClusterTimecode = aFrame->GetTimeStamp() / PR_USEC_PER_MSEC;
Ebml_SerializeUnsigned(&ebml, Timecode, mClusterTimecode);
mFlushState |= FLUSH_CLUSTER;
}
bool isOpus = (frameType == EncodedFrame::FrameType::OPUS_AUDIO_FRAME);
// Can't underflow/overflow now
int64_t timeCode = aFrame->GetTimeStamp() / ((int) PR_USEC_PER_MSEC) - mClusterTimecode;
if (isOpus) {
timeCode += mCodecDelay / PR_NSEC_PER_MSEC;
}
MOZ_ASSERT(timeCode >= SHRT_MIN && timeCode <= SHRT_MAX);
writeSimpleBlock(&ebml, isOpus ? 0x2 : 0x1, static_cast<short>(timeCode), isVP8IFrame,
0, 0, (unsigned char*)aFrame->GetFrameData().Elements(),
aFrame->GetFrameData().Length());
MOZ_ASSERT(ebml.offset <= DEFAULT_HEADER_SIZE +
aFrame->GetFrameData().Length(),
"write more data > EBML_BUFFER_SIZE");
block->SetLength(ebml.offset);
}
void
EbmlComposer::SetVideoConfig(uint32_t aWidth, uint32_t aHeight,
uint32_t aDisplayWidth, uint32_t aDisplayHeight,
float aFrameRate)
{
MOZ_ASSERT(aWidth > 0, "Width should > 0");
MOZ_ASSERT(aHeight > 0, "Height should > 0");
MOZ_ASSERT(aDisplayWidth > 0, "DisplayWidth should > 0");
MOZ_ASSERT(aDisplayHeight > 0, "DisplayHeight should > 0");
MOZ_ASSERT(aFrameRate > 0, "FrameRate should > 0");
mWidth = aWidth;
mHeight = aHeight;
mDisplayWidth = aDisplayWidth;
mDisplayHeight = aDisplayHeight;
mFrameRate = aFrameRate;
}
void
EbmlComposer::SetAudioConfig(uint32_t aSampleFreq, uint32_t aChannels)
{
MOZ_ASSERT(aSampleFreq > 0, "SampleFreq should > 0");
MOZ_ASSERT(aChannels > 0, "Channels should > 0");
mSampleFreq = aSampleFreq;
mChannels = aChannels;
}
void
EbmlComposer::ExtractBuffer(nsTArray<nsTArray<uint8_t> >* aDestBufs,
uint32_t aFlag)
{
if ((aFlag & ContainerWriter::FLUSH_NEEDED) ||
(aFlag & ContainerWriter::GET_HEADER))
{
FinishMetadata();
}
if (aFlag & ContainerWriter::FLUSH_NEEDED)
{
FinishCluster();
}
// aDestBufs may have some element
for (uint32_t i = 0; i < mClusterCanFlushBuffs.Length(); i++) {
aDestBufs->AppendElement()->SwapElements(mClusterCanFlushBuffs[i]);
}
mClusterCanFlushBuffs.Clear();
}
EbmlComposer::EbmlComposer()
: mFlushState(FLUSH_NONE)
, mClusterHeaderIndex(0)
, mClusterLengthLoc(0)
, mCodecDelay(0)
, mClusterTimecode(0)
, mWidth(0)
, mHeight(0)
, mFrameRate(0)
, mSampleFreq(0)
, mChannels(0)
{}
} // namespace mozilla
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