我已经从混合现实webbrtc获得了30 fps的I420视频帧。我使用以下代码创建媒体示例，并将框架从webrtc复制到此媒体示例，并将其附加到从MediaStreamSource生成的示例。SampleRequested事件。但是在每次创建媒体流样本的UWP应用程序中有更多的媒体播放器，渲染体验看起来不太好。
据说媒体流样本时间戳可以在非托管代码中更新，而不需要用更新的时间戳创建新的媒体流样本，从而节省了GC所花费的时间。但我不确定怎么做。有人能告诉我如何在非托管代码中实现这一点吗?
public class StreamSamplePool
{
/// <summary>
/// Queue of buffers in use by a sample.
/// </summary>
/// <remarks>
/// Newly used buffers are added on the back of the queue, and removed
/// from the front once the <see cref="Windows.Media.Core.MediaStreamSample.Processed"/>
/// signal is fired. Because some users report out-of-order or missing
/// calls, all earlier buffers are also removed, so order of the buffers
/// in the queue reflects the chronology and matters.
/// </remarks>
Queue<Buffer> _usedBuffers;
/// <summary>
/// Stack of free buffers available for recycling by a new sample.
/// </summary>
/// <remarks>
/// Since buffer resize shall correspond to video resize and thus be infrequent,
/// favor reusing the last released buffer, which is most likely to have the same
/// capacity as the new frame, by using a stack.
/// </remarks>
Stack<Buffer> _freeBuffers;
/// <summary>
/// Construct a new pool of buffers.
/// </summary>
/// <param name="capacity">Initial capacity of both the used and free collections of buffers</param>
public StreamSamplePool(int capacity)
{
this._usedBuffers = new Queue<Buffer>(capacity);
this._freeBuffers = new Stack<Buffer>(capacity);
}
/// <summary>
/// Get a sample from the pool which has a buffer with a given capacity
/// and with the associated timestamp.
/// </summary>
/// <param name="byteSize">The exact size in bytes that the sample buffer needs to accomodate.</param>
/// <param name="timestamp">The sample presentation timestamp.</param>
/// <returns>The newly created sample</returns>
/// <remarks>
/// The returned sample's buffer has a <see cref="Windows.Storage.Streams.Buffer.Length"/> property
/// set to the input <see cref="byteSize"/>. This is required to be set before creating the sample,
/// and should not be modified once the sample was created.
/// </remarks>
public MediaStreamSample Pop(uint byteSize, System.TimeSpan timestamp)
{
Buffer buffer;
lock (this)
{
if (_freeBuffers.Count > 0)
{
buffer = _freeBuffers.Pop();
if (buffer.Capacity < byteSize)
{
buffer = new Buffer(byteSize);
}
}
else
{
buffer = new Buffer(byteSize);
}
_usedBuffers.Enqueue(buffer);
// This must be set before calling CreateFromBuffer() below otherwise
// the Media Foundation pipeline throws an exception.
buffer.Length = byteSize;
}
// Because the managed wrapper does not allow modifying the timestamp,
// need to recreate the sample each time with the correct timestamp.
var sample = MediaStreamSample.CreateFromBuffer(buffer, timestamp);
sample.Processed += OnSampleProcessed;
return sample;
}
/// <summary>
/// Callback fired by MediaFoundation when a <see cref="Windows.Media.Core.MediaStreamSample"/>
/// has been processed by the pipeline and its buffer can be reused.
/// </summary>
/// <param name="sample">The sample which has been processed.</param>
/// <param name="args"></param>
private void OnSampleProcessed(MediaStreamSample sample, object args)
{
lock (this)
{
// This does a linear search from front, which generally finds
// the first object (oldest) or at worse one very close to front,
// so is optimal anyway.
// Remove this sample and all earlier ones too. Some users report that
// the Processed event is not always reported for earlier samples, which
// would result in memory leaks. This may be due to out-of-order reporting.
while (_usedBuffers.TryDequeue(out Buffer buffer))
{
// Save the buffer for later reuse
_freeBuffers.Push(buffer);
if (buffer == sample.Buffer)
{
break;
}
}
}
}
}
我已经咨询了团队。我收到了一家媒体中小企业的回复。因此，不幸的是，答案是没有办法实现您想要做的事情，特别是因为Timestamp属性是只读的。你所做的是你所能得到的最优的，你不能用MediaStreamSample做得更好。