gecko/content/media/nsMediaDecoder.cpp

221 lines
6.3 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim:set ts=2 sw=2 sts=2 et cindent: */
/* 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 "nsMediaDecoder.h"
#include "MediaResource.h"
#include "nsHTMLMediaElement.h"
#include "nsError.h"
using namespace mozilla;
// Number of milliseconds between progress events as defined by spec
static const PRUint32 PROGRESS_MS = 350;
// Number of milliseconds of no data before a stall event is fired as defined by spec
static const PRUint32 STALL_MS = 3000;
// Number of estimated seconds worth of data we need to have buffered
// ahead of the current playback position before we allow the media decoder
// to report that it can play through the entire media without the decode
// catching up with the download. Having this margin make the
// nsMediaDecoder::CanPlayThrough() calculation more stable in the case of
// fluctuating bitrates.
static const PRInt64 CAN_PLAY_THROUGH_MARGIN = 10;
nsMediaDecoder::nsMediaDecoder() :
mElement(nullptr),
mFrameBufferLength(0),
mPinnedForSeek(false),
mShuttingDown(false)
{
MOZ_COUNT_CTOR(nsMediaDecoder);
MediaMemoryReporter::AddMediaDecoder(this);
}
nsMediaDecoder::~nsMediaDecoder()
{
MOZ_COUNT_DTOR(nsMediaDecoder);
MediaMemoryReporter::RemoveMediaDecoder(this);
}
bool nsMediaDecoder::Init(nsHTMLMediaElement* aElement)
{
mElement = aElement;
mVideoFrameContainer = aElement->GetVideoFrameContainer();
return true;
}
void nsMediaDecoder::Shutdown()
{
StopProgress();
mElement = nullptr;
}
nsHTMLMediaElement* nsMediaDecoder::GetMediaElement()
{
return mElement;
}
nsresult nsMediaDecoder::RequestFrameBufferLength(PRUint32 aLength)
{
if (aLength < FRAMEBUFFER_LENGTH_MIN || aLength > FRAMEBUFFER_LENGTH_MAX) {
return NS_ERROR_DOM_INDEX_SIZE_ERR;
}
mFrameBufferLength = aLength;
return NS_OK;
}
static void ProgressCallback(nsITimer* aTimer, void* aClosure)
{
nsMediaDecoder* decoder = static_cast<nsMediaDecoder*>(aClosure);
decoder->Progress(true);
}
void nsMediaDecoder::Progress(bool aTimer)
{
if (!mElement)
return;
TimeStamp now = TimeStamp::Now();
if (!aTimer) {
mDataTime = now;
}
// If PROGRESS_MS has passed since the last progress event fired and more
// data has arrived since then, fire another progress event.
if ((mProgressTime.IsNull() ||
now - mProgressTime >= TimeDuration::FromMilliseconds(PROGRESS_MS)) &&
!mDataTime.IsNull() &&
now - mDataTime <= TimeDuration::FromMilliseconds(PROGRESS_MS)) {
mElement->DispatchAsyncEvent(NS_LITERAL_STRING("progress"));
mProgressTime = now;
}
if (!mDataTime.IsNull() &&
now - mDataTime >= TimeDuration::FromMilliseconds(STALL_MS)) {
mElement->DownloadStalled();
// Null it out
mDataTime = TimeStamp();
}
}
nsresult nsMediaDecoder::StartProgress()
{
if (mProgressTimer)
return NS_OK;
mProgressTimer = do_CreateInstance("@mozilla.org/timer;1");
return mProgressTimer->InitWithFuncCallback(ProgressCallback,
this,
PROGRESS_MS,
nsITimer::TYPE_REPEATING_SLACK);
}
nsresult nsMediaDecoder::StopProgress()
{
if (!mProgressTimer)
return NS_OK;
nsresult rv = mProgressTimer->Cancel();
mProgressTimer = nullptr;
return rv;
}
void nsMediaDecoder::FireTimeUpdate()
{
if (!mElement)
return;
mElement->FireTimeUpdate(true);
}
void nsMediaDecoder::PinForSeek()
{
MediaResource* resource = GetResource();
if (!resource || mPinnedForSeek) {
return;
}
mPinnedForSeek = true;
resource->Pin();
}
void nsMediaDecoder::UnpinForSeek()
{
MediaResource* resource = GetResource();
if (!resource || !mPinnedForSeek) {
return;
}
mPinnedForSeek = false;
resource->Unpin();
}
bool nsMediaDecoder::CanPlayThrough()
{
Statistics stats = GetStatistics();
if (!stats.mDownloadRateReliable || !stats.mPlaybackRateReliable) {
return false;
}
PRInt64 bytesToDownload = stats.mTotalBytes - stats.mDownloadPosition;
PRInt64 bytesToPlayback = stats.mTotalBytes - stats.mPlaybackPosition;
double timeToDownload = bytesToDownload / stats.mDownloadRate;
double timeToPlay = bytesToPlayback / stats.mPlaybackRate;
if (timeToDownload > timeToPlay) {
// Estimated time to download is greater than the estimated time to play.
// We probably can't play through without having to stop to buffer.
return false;
}
// Estimated time to download is less than the estimated time to play.
// We can probably play through without having to buffer, but ensure that
// we've got a reasonable amount of data buffered after the current
// playback position, so that if the bitrate of the media fluctuates, or if
// our download rate or decode rate estimation is otherwise inaccurate,
// we don't suddenly discover that we need to buffer. This is particularly
// required near the start of the media, when not much data is downloaded.
PRInt64 readAheadMargin =
static_cast<PRInt64>(stats.mPlaybackRate * CAN_PLAY_THROUGH_MARGIN);
return stats.mTotalBytes == stats.mDownloadPosition ||
stats.mDownloadPosition > stats.mPlaybackPosition + readAheadMargin;
}
namespace mozilla {
MediaMemoryReporter* MediaMemoryReporter::sUniqueInstance;
NS_MEMORY_REPORTER_IMPLEMENT(MediaDecodedVideoMemory,
"explicit/media/decoded-video",
KIND_HEAP,
UNITS_BYTES,
MediaMemoryReporter::GetDecodedVideoMemory,
"Memory used by decoded video frames.")
NS_MEMORY_REPORTER_IMPLEMENT(MediaDecodedAudioMemory,
"explicit/media/decoded-audio",
KIND_HEAP,
UNITS_BYTES,
MediaMemoryReporter::GetDecodedAudioMemory,
"Memory used by decoded audio chunks.")
MediaMemoryReporter::MediaMemoryReporter()
: mMediaDecodedVideoMemory(new NS_MEMORY_REPORTER_NAME(MediaDecodedVideoMemory))
, mMediaDecodedAudioMemory(new NS_MEMORY_REPORTER_NAME(MediaDecodedAudioMemory))
{
NS_RegisterMemoryReporter(mMediaDecodedVideoMemory);
NS_RegisterMemoryReporter(mMediaDecodedAudioMemory);
}
MediaMemoryReporter::~MediaMemoryReporter()
{
NS_UnregisterMemoryReporter(mMediaDecodedVideoMemory);
NS_UnregisterMemoryReporter(mMediaDecodedAudioMemory);
}
} // namespace mozilla