/// <summary>
/// Initializes the media block buffers and
/// starts packet reader, frame decoder, and block rendering workers.
/// </summary>
internal void StartWorkers()
{
// Initialize the block buffers
foreach (var t in Container.Components.MediaTypes)
{
Blocks[t] = new MediaBlockBuffer(Constants.MaxBlocks[t], t);
Renderers[t] = Platform.CreateRenderer(t, this);
InvalidateRenderer(t);
}
// Create the renderer for the preloaded subs
if (PreloadedSubtitles != null)
{
Renderers[PreloadedSubtitles.MediaType] = Platform.CreateRenderer(PreloadedSubtitles.MediaType, this);
InvalidateRenderer(PreloadedSubtitles.MediaType);
}
Clock.SpeedRatio = Constants.Controller.DefaultSpeedRatio;
Commands.IsStopWorkersPending = false;
// Set the initial state of the task cycles.
BlockRenderingCycle.Complete();
FrameDecodingCycle.Begin();
PacketReadingCycle.Begin();
// Create the thread runners
PacketReadingTask = new Thread(RunPacketReadingWorker)
{
IsBackground = true, Name = nameof(PacketReadingTask), Priority = ThreadPriority.Normal
};
FrameDecodingTask = new Thread(RunFrameDecodingWorker)
{
IsBackground = true, Name = nameof(FrameDecodingTask), Priority = ThreadPriority.AboveNormal
};
// Fire up the threads
PacketReadingTask.Start();
FrameDecodingTask.Start();
StartBlockRenderingWorker();
}
/// <summary>
/// Continually decodes the available packet buffer to have as
/// many frames as possible in each frame queue and
/// up to the MaxFrames on each component
/// </summary>
internal void RunFrameDecodingWorker()
{
#region Worker State Setup
// The delay provider prevents 100% core usage
var delay = new DelayProvider();
// State variables
var decodedFrameCount = 0;
var wallClock = TimeSpan.Zero;
var rangePercent = 0d;
var isInRange = false;
var playAfterSeek = false;
// Holds the main media type
var main = Container.Components.Main.MediaType;
// Holds the auxiliary media types
var auxs = Container.Components.MediaTypes.ExcludeMediaType(main);
// Holds all components
var all = Container.Components.MediaTypes.DeepCopy();
var isBuffering = false;
var resumeClock = false;
var hasPendingSeeks = false;
MediaComponent comp = null;
MediaBlockBuffer blocks = null;
#endregion
#region Worker Loop
try
{
while (IsTaskCancellationPending == false)
{
#region 1. Setup the Decoding Cycle
// Singal a Seek starting operation
hasPendingSeeks = Commands.PendingCountOf(MediaCommandType.Seek) > 0;
if (State.IsSeeking == false && hasPendingSeeks)
{
playAfterSeek = State.IsPlaying;
State.IsSeeking = true;
SendOnSeekingStarted();
}
// Execute the following command at the beginning of the cycle
Commands.ProcessNext();
// Wait for a seek operation to complete (if any)
// and initiate a frame decoding cycle.
SeekingDone.Wait();
// Set initial state
wallClock = WallClock;
decodedFrameCount = 0;
// Signal a Seek ending operation
// TOD: Maybe this should go on the block rendering worker?
hasPendingSeeks = Commands.PendingCountOf(MediaCommandType.Seek) > 0;
if (State.IsSeeking && hasPendingSeeks == false)
{
// Detect a end of seek cycle and update to the final position
wallClock = SnapToFramePosition(WallClock);
Clock.Update(wallClock);
State.UpdatePosition(wallClock);
// Call the seek method on all renderers
foreach (var kvp in Renderers)
{
LastRenderTime[kvp.Key] = TimeSpan.MinValue;
kvp.Value.Seek();
}
SendOnSeekingEnded();
State.IsSeeking = false;
if (playAfterSeek)
{
Clock.Play();
State.UpdateMediaState(PlaybackStatus.Play);
}
else
{
State.UpdateMediaState(PlaybackStatus.Pause);
}
}
else if (State.IsSeeking == false)
{
// Notify position changes
State.UpdatePosition(wallClock);
}
// Initiate the frame docding cycle
FrameDecodingCycle.Begin();
#endregion
#region 2. Main Component Decoding
// Capture component and blocks for easier readability
comp = Container.Components[main];
blocks = Blocks[main];
// Handle the main component decoding; Start by checking we have some packets
while (comp.PacketBufferCount <= 0 && CanReadMorePackets && ShouldReadMorePackets)
{
PacketReadingCycle.Wait(Constants.Interval.LowPriority);
}
if (comp.PacketBufferCount > 0)
{
// Detect if we are in range for the main component
isInRange = blocks.IsInRange(wallClock);
if (isInRange == false)
{
// Signal the start of a sync-buffering scenario
HasDecoderSeeked = true;
isBuffering = true;
resumeClock = Clock.IsRunning;
Clock.Pause();
Log(MediaLogMessageType.Debug, $"SYNC-BUFFER: Started.");
// Read some frames and try to get a valid range
do
{
// Try to get more packets by waiting for read cycles.
if (CanReadMorePackets && comp.PacketBufferCount <= 0)
{
PacketReadingCycle.Wait();
}
// Decode some frames and check if we are in reange now
decodedFrameCount += AddBlocks(main);
isInRange = blocks.IsInRange(wallClock);
// Break the cycle if we are in range
if (isInRange || CanReadMorePackets == false)
{
break;
}
}while (decodedFrameCount <= 0 && blocks.IsFull == false);
// Unfortunately at this point we will need to adjust the clock after creating the frames.
// to ensure tha mian component is within the clock range if the decoded
// frames are not with range. This is normal while buffering though.
if (isInRange == false)
{
// Update the wall clock to the most appropriate available block.
if (blocks.Count > 0)
{
wallClock = blocks[wallClock].StartTime;
}
else
{
resumeClock = false; // Hard stop the clock.
}
// Update the clock to what the main component range mandates
Clock.Update(wallClock);
// Call seek to invalidate renderer
LastRenderTime[main] = TimeSpan.MinValue;
Renderers[main].Seek();
// Try to recover the regular loop
isInRange = true;
while (CanReadMorePackets && comp.PacketBufferCount <= 0)
{
PacketReadingCycle.Wait();
}
}
}
if (isInRange)
{
// Check if we need more blocks for the current components
rangePercent = blocks.GetRangePercent(wallClock);
// Read as much as we can for this cycle.
while (comp.PacketBufferCount > 0)
{
rangePercent = blocks.GetRangePercent(wallClock);
if (blocks.IsFull == false || (blocks.IsFull && rangePercent > 0.75d && rangePercent < 1d))
{
decodedFrameCount += AddBlocks(main);
}
else
{
break;
}
}
}
}
#endregion
#region 3. Auxiliary Component Decoding
foreach (var t in auxs)
{
if (State.IsSeeking)
{
continue;
}
// Capture the current block buffer and component
// for easier readability
comp = Container.Components[t];
blocks = Blocks[t];
isInRange = blocks.IsInRange(wallClock);
// Invalidate the renderer if we don't have the block.
if (isInRange == false)
{
LastRenderTime[t] = TimeSpan.MinValue;
Renderers[t].Seek();
}
// wait for component to get there if we only have furutre blocks
// in auxiliary component.
if (blocks.Count > 0 && blocks.RangeStartTime > wallClock)
{
continue;
}
// Try to catch up with the wall clock
while (blocks.Count == 0 || blocks.RangeEndTime <= wallClock)
{
// Wait for packets if we don't have enough packets
if (CanReadMorePackets && comp.PacketBufferCount <= 0)
{
PacketReadingCycle.Wait();
}
if (comp.PacketBufferCount <= 0)
{
break;
}
else
{
decodedFrameCount += AddBlocks(t);
}
}
isInRange = blocks.IsInRange(wallClock);
// Move to the next component if we don't meet a regular conditions
if (isInRange == false || isBuffering || comp.PacketBufferCount <= 0)
{
continue;
}
// Read as much as we can for this cycle.
while (comp.PacketBufferCount > 0)
{
rangePercent = blocks.GetRangePercent(wallClock);
if (blocks.IsFull == false || (blocks.IsFull && rangePercent > 0.75d && rangePercent < 1d))
{
decodedFrameCount += AddBlocks(t);
}
else
{
break;
}
}
}
#endregion
#region 4. Detect End of Media
// Detect end of block rendering
// TODO: Maybe this detection should be performed on the BlockRendering worker?
if (isBuffering == false &&
State.IsSeeking == false &&
CanReadMoreFramesOf(main) == false &&
Blocks[main].IndexOf(wallClock) == Blocks[main].Count - 1)
{
if (State.HasMediaEnded == false)
{
// Rendered all and nothing else to read
Clock.Pause();
if (State.NaturalDuration != null && State.NaturalDuration != TimeSpan.MinValue)
{
wallClock = State.NaturalDuration.Value;
}
else
{
wallClock = Blocks[main].RangeEndTime;
}
Clock.Update(wallClock);
State.HasMediaEnded = true;
State.UpdateMediaState(PlaybackStatus.Stop, wallClock);
SendOnMediaEnded();
}
}
else
{
State.HasMediaEnded = false;
}
#endregion
#region 6. Finish the Cycle
// complete buffering notifications
if (isBuffering)
{
// Reset the buffering flag
isBuffering = false;
// Resume the clock if it was playing
if (resumeClock)
{
Clock.Play();
}
// log some message
Log(
MediaLogMessageType.Debug,
$"SYNC-BUFFER: Finished. Clock set to {wallClock.Format()}");
}
// Complete the frame decoding cycle
FrameDecodingCycle.Complete();
// After a seek operation, always reset the has seeked flag.
HasDecoderSeeked = false;
// If not already set, guess the 1-second buffer length
State.GuessBufferingProperties();
// Give it a break if there was nothing to decode.
// We probably need to wait for some more input
if (decodedFrameCount <= 0 && Commands.PendingCount <= 0)
{
delay.WaitOne();
}
#endregion
}
}
catch (ThreadAbortException) { /* swallow */ }
catch { if (!IsDisposed)
{
throw;
}
}
finally
{
// Always exit notifying the cycle is done.
FrameDecodingCycle.Complete();
delay.Dispose();
}
#endregion
}
/// <summary>
/// Continually decodes the available packet buffer to have as
/// many frames as possible in each frame queue and
/// up to the MaxFrames on each component
/// </summary>
internal void RunFrameDecodingWorker()
{
// TODO: Don't use State properties in workers as they are only for
// TODO: Check the use of wall clock. Maybe it's be more consistent
// to use a single atomic wallclock value per cycle. Check other workers as well.
// state notification purposes.
// State variables
var wasSyncBuffering = false;
var delay = new DelayProvider(); // The delay provider prevents 100% core usage
var decodedFrameCount = 0;
var rangePercent = 0d;
var main = Container.Components.MainMediaType; // Holds the main media type
var resumeSyncBufferingClock = false;
MediaBlockBuffer blocks = null;
try
{
while (Commands.IsStopWorkersPending == false)
{
#region Setup the Decoding Cycle
// Determine what to do on a priority command
if (Commands.IsExecutingDirectCommand)
{
if (Commands.IsClosing)
{
break;
}
if (Commands.IsChanging)
{
Commands.WaitForDirectCommand();
}
}
// Execute the following command at the beginning of the cycle
if (IsSyncBuffering == false)
{
Commands.ExecuteNextQueuedCommand();
}
// Signal a Seek starting operation and set the initial state
FrameDecodingCycle.Begin();
// Update state properties -- this must be after processing commanmds as
// a direct command might have changed the components
main = Container.Components.MainMediaType;
decodedFrameCount = 0;
#endregion
// The 2-part logic blocks detect a sync-buffering scenario
// and then decodes the necessary frames.
if (State.HasMediaEnded == false && IsWorkerInterruptRequested == false)
{
#region Sync-Buffering
// Capture the blocks for easier readability
blocks = Blocks[main];
// If we are not then we need to begin sync-buffering
if (wasSyncBuffering == false && blocks.IsInRange(WallClock) == false)
{
// Signal the start of a sync-buffering scenario
IsSyncBuffering = true;
wasSyncBuffering = true;
resumeSyncBufferingClock = Clock.IsRunning;
Clock.Pause();
State.UpdateMediaState(PlaybackStatus.Manual);
Log(MediaLogMessageType.Debug, $"SYNC-BUFFER: Started.");
}
#endregion
#region Component Decoding
// We need to add blocks if the wall clock is over 75%
// for each of the components so that we have some buffer.
foreach (var t in Container.Components.MediaTypes)
{
if (IsWorkerInterruptRequested)
{
break;
}
// Capture a reference to the blocks and the current Range Percent
const double rangePercentThreshold = 0.75d;
blocks = Blocks[t];
rangePercent = blocks.GetRangePercent(WallClock);
// Read as much as we can for this cycle but always within range.
while (blocks.IsFull == false || rangePercent > rangePercentThreshold)
{
// Stop decoding under sync-buffering conditions
if (IsSyncBuffering && blocks.IsFull)
{
break;
}
if (IsWorkerInterruptRequested || AddNextBlock(t) == false)
{
break;
}
decodedFrameCount += 1;
rangePercent = blocks.GetRangePercent(WallClock);
// Determine break conditions to save CPU time
if (IsSyncBuffering == false &&
rangePercent > 0 &&
rangePercent <= rangePercentThreshold &&
blocks.IsFull == false &&
blocks.CapacityPercent >= 0.25d &&
blocks.IsInRange(WallClock))
{
break;
}
}
}
// Give it a break if we are still buffering packets
if (IsSyncBuffering)
{
delay.WaitOne();
FrameDecodingCycle.Complete();
continue;
}
#endregion
}
#region Finish the Cycle
// Detect End of Media Scenarios
DetectEndOfMedia(decodedFrameCount, main);
// Resume sync-buffering clock
if (wasSyncBuffering && IsSyncBuffering == false)
{
// Sync-buffering blocks
blocks = Blocks[main];
// Unfortunately at this point we will need to adjust the clock after creating the frames.
// to ensure tha mian component is within the clock range if the decoded
// frames are not with range. This is normal while buffering though.
if (blocks.IsInRange(WallClock) == false)
{
// Update the wall clock to the most appropriate available block.
if (blocks.Count > 0)
{
ChangePosition(blocks[WallClock].StartTime);
}
else
{
resumeSyncBufferingClock = false; // Hard stop the clock.
}
}
// log some message and resume the clock if it was playing
Log(MediaLogMessageType.Debug, $"SYNC-BUFFER: Finished. Clock set to {WallClock.Format()}");
if (resumeSyncBufferingClock && State.HasMediaEnded == false)
{
ResumePlayback();
}
wasSyncBuffering = false;
resumeSyncBufferingClock = false;
}
// Provide updates to decoding stats
State.UpdateDecodingBitrate(
Blocks.Values.Sum(b => b.IsInRange(WallClock) ? b.RangeBitrate : 0));
// Complete the frame decoding cycle
FrameDecodingCycle.Complete();
// Give it a break if there was nothing to decode.
DelayDecoder(delay, decodedFrameCount);
#endregion
}
}
catch { throw; }
finally
{
// Reset decoding stats
State.UpdateDecodingBitrate(0);
// Always exit notifying the cycle is done.
FrameDecodingCycle.Complete();
delay.Dispose();
}
}
/// <summary>
/// Continually decodes the available packet buffer to have as
/// many frames as possible in each frame queue and
/// up to the MaxFrames on each component
/// </summary>
internal void RunFrameDecodingWorker()
{
#region Worker State Setup
// The delay provider prevents 100% core usage
var delay = new DelayProvider();
// State variables
var decodedFrameCount = 0;
var wallClock = TimeSpan.Zero;
var rangePercent = 0d;
var isInRange = false;
// Holds the main media type
var main = Container.Components.Main.MediaType;
// Holds the auxiliary media types
var auxs = Container.Components.MediaTypes.Except(main);
// State properties
var isBuffering = false;
var resumeClock = false;
MediaComponent comp = null;
MediaBlockBuffer blocks = null;
#endregion
#region Worker Loop
try
{
while (Commands.IsStopWorkersPending == false)
{
#region 1. Setup the Decoding Cycle
// Determine what to do on a priority command
if (Commands.IsExecutingDirectCommand)
{
if (Commands.IsClosing)
{
break;
}
if (Commands.IsChanging)
{
Commands.WaitForDirectCommand();
}
}
// Update state properties -- this must be after processing commanmds as
// a direct command might have changed the components
main = Container.Components.Main.MediaType;
auxs = Container.Components.MediaTypes.Except(main);
// Execute the following command at the beginning of the cycle
Commands.ExecuteNextQueuedCommand();
// Signal a Seek starting operation
FrameDecodingCycle.Begin();
// Set initial state
wallClock = WallClock;
decodedFrameCount = 0;
#endregion
if (State.HasMediaEnded == false)
{
#region 2. Main Component Decoding
// Capture component and blocks for easier readability
// comp is current component, blocks is the block collection for the component
comp = Container.Components[main];
blocks = Blocks[main];
// Detect if we are in range for the main component
isInRange = blocks.IsInRange(wallClock);
if (isInRange == false)
{
// Signal the start of a sync-buffering scenario
isBuffering = true;
State.SignalBufferingStarted();
resumeClock = Clock.IsRunning;
Clock.Pause();
Log(MediaLogMessageType.Debug, $"SYNC-BUFFER: Started.");
// Read some frames and try to get a valid range
do
{
// Try to get more packets by waiting for read cycles.
WaitForPackets(comp, 1);
// Decode some frames and check if we are in reange now
if (AddNextBlock(main) == false)
{
break;
}
decodedFrameCount += 1;
isInRange = blocks.IsInRange(wallClock);
// Break the cycle if we are in range
if (isInRange || CanReadMorePackets == false || ShouldReadMorePackets == false)
{
break;
}
}while (blocks.IsFull == false);
// Unfortunately at this point we will need to adjust the clock after creating the frames.
// to ensure tha mian component is within the clock range if the decoded
// frames are not with range. This is normal while buffering though.
if (isInRange == false)
{
// Update the wall clock to the most appropriate available block.
if (blocks.Count > 0)
{
wallClock = blocks[wallClock].StartTime;
}
else
{
resumeClock = false; // Hard stop the clock.
}
// Update the clock to what the main component range mandates
Clock.Update(wallClock);
// Force renderer invalidation
InvalidateRenderer(main);
// Try to recover the regular loop
isInRange = true;
}
}
if (isInRange)
{
// Check if we need more blocks for the current components
rangePercent = blocks.GetRangePercent(wallClock);
// Read as much as we can for this cycle but always within range.
while (blocks.IsFull == false || (blocks.IsFull && rangePercent > 0.75d && rangePercent < 1d))
{
if (AddNextBlock(main) == false)
{
break;
}
decodedFrameCount += 1;
rangePercent = blocks.GetRangePercent(wallClock);
continue;
}
}
#endregion
#region 3. Auxiliary Component Decoding
foreach (var t in auxs)
{
if (State.IsSeeking)
{
continue;
}
// Capture the current block buffer and component
// for easier readability
comp = Container.Components[t];
blocks = Blocks[t];
isInRange = blocks.IsInRange(wallClock);
// wait for component to get there if we only have furutre blocks
// in auxiliary component.
if (blocks.Count > 0 && blocks.RangeStartTime > wallClock)
{
continue;
}
// We need the other components to catch up with the main
while (blocks.Count == 0 || blocks.RangeEndTime <= wallClock ||
(Blocks[main].Count > 0 && blocks.RangeEndTime < Blocks[main].RangeEndTime))
{
// give up if we never received frames for the expected component
if (AddNextBlock(t) == false)
{
break;
}
}
// Check if we are finally within range
isInRange = blocks.IsInRange(wallClock);
// Invalidate the renderer if we don't have the block.
if (isInRange == false)
{
InvalidateRenderer(t);
}
// Move to the next component if we don't meet a regular conditions
if (isInRange == false || isBuffering)
{
continue;
}
// Decode as much as we can off the packet buffer for this cycle.
rangePercent = blocks.GetRangePercent(wallClock);
while (blocks.IsFull == false || (blocks.IsFull && rangePercent > 0.75d && rangePercent < 1d))
{
if (AddNextBlock(t) == false)
{
break;
}
rangePercent = blocks.GetRangePercent(wallClock);
}
}
#endregion
}
#region 4. Detect End of Media
// Detect end of block rendering
// TODO: Maybe this detection should be performed on the BlockRendering worker?
if (isBuffering == false &&
decodedFrameCount <= 0 &&
State.IsSeeking == false &&
CanReadMoreFramesOf(main) == false &&
Blocks[main].IndexOf(wallClock) == Blocks[main].Count - 1)
{
if (State.HasMediaEnded == false)
{
// Rendered all and nothing else to read
Clock.Pause();
wallClock = Blocks[main].RangeEndTime;
Clock.Update(wallClock);
if (State.NaturalDuration != null &&
State.NaturalDuration != TimeSpan.MinValue &&
State.NaturalDuration < wallClock)
{
Log(MediaLogMessageType.Warning,
$"{nameof(State.HasMediaEnded)} conditions met at {wallClock.Format()} but " +
$"{nameof(State.NaturalDuration)} reports {State.NaturalDuration.Value.Format()}");
}
State.UpdateMediaEnded(true);
State.UpdateMediaState(PlaybackStatus.Stop, wallClock);
SendOnMediaEnded();
}
}
else
{
State.UpdateMediaEnded(false);
}
#endregion
#region 6. Finish the Cycle
// complete buffering notifications
if (isBuffering)
{
// Always reset the buffering flag
isBuffering = false;
// Resume the clock if it was playing
if (resumeClock)
{
Clock.Play();
}
// log some message
Log(MediaLogMessageType.Debug, $"SYNC-BUFFER: Finished. Clock set to {wallClock.Format()}");
}
// If not already set, guess the 1-second buffer length
State.GuessBufferingProperties();
// Complete the frame decoding cycle
FrameDecodingCycle.Complete();
// Give it a break if there was nothing to decode.
// We probably need to wait for some more input
if (Commands.IsStopWorkersPending == false &&
decodedFrameCount <= 0 &&
Commands.HasQueuedCommands == false)
{
delay.WaitOne();
}
#endregion
}
}
catch { throw; }
finally
{
// Always exit notifying the cycle is done.
FrameDecodingCycle.Complete();
delay.Dispose();
}
#endregion
}