webrtc/modules/utility/source/video_frames_queue.cc

/*
 *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */

#include "video_frames_queue.h"

#ifdef WEBRTC_MODULE_UTILITY_VIDEO

#include <cassert>

#include "module_common_types.h"
#include "tick_util.h"
#include "trace.h"

namespace webrtc {
VideoFramesQueue::VideoFramesQueue()
    : _incomingFrames(),
      _renderDelayMs(10)
{
}

VideoFramesQueue::~VideoFramesQueue()
{
    while (!_incomingFrames.Empty())
    {
        ListItem* item = _incomingFrames.First();
        if (item)
        {
            I420VideoFrame* ptrFrame =
              static_cast<I420VideoFrame*>(item->GetItem());
            assert(ptrFrame != NULL);
            delete ptrFrame;
        }
        _incomingFrames.Erase(item);
    }
    while (!_emptyFrames.Empty())
    {
        ListItem* item = _emptyFrames.First();
        _emptyFrames.Erase(item);
    }
}

WebRtc_Word32 VideoFramesQueue::AddFrame(const I420VideoFrame& newFrame)
{
    I420VideoFrame* ptrFrameToAdd = NULL;
    // Try to re-use a VideoFrame. Only allocate new memory if it is necessary.
    if (!_emptyFrames.Empty())
    {
        ListItem* item = _emptyFrames.First();
        if (item)
        {
            ptrFrameToAdd = static_cast<I420VideoFrame*>(item->GetItem());
            _emptyFrames.Erase(item);
        }
    }
    if (!ptrFrameToAdd)
    {
        if (_emptyFrames.GetSize() + _incomingFrames.GetSize() >
            KMaxNumberOfFrames)
        {
            WEBRTC_TRACE(kTraceWarning, kTraceVideoRenderer, -1,
                         "%s: too many frames, limit: %d", __FUNCTION__,
                         KMaxNumberOfFrames);
            return -1;
        }

        WEBRTC_TRACE(kTraceMemory, kTraceVideoRenderer, -1,
                     "%s: allocating buffer %d", __FUNCTION__,
                     _emptyFrames.GetSize() + _incomingFrames.GetSize());

        ptrFrameToAdd = new I420VideoFrame();
        if (!ptrFrameToAdd)
        {
            WEBRTC_TRACE(kTraceError, kTraceVideoRenderer, -1,
                         "%s: could not create new frame for", __FUNCTION__);
            return -1;
        }
    }
    ptrFrameToAdd->CopyFrame(newFrame);
    _incomingFrames.PushBack(ptrFrameToAdd);
    return 0;
}

// Find the most recent frame that has a VideoFrame::RenderTimeMs() that is
// lower than current time in ms (TickTime::MillisecondTimestamp()).
// Note _incomingFrames is sorted so that the oldest frame is first.
// Recycle all frames that are older than the most recent frame.
I420VideoFrame* VideoFramesQueue::FrameToRecord()
{
    I420VideoFrame* ptrRenderFrame = NULL;
    ListItem* item = _incomingFrames.First();
    while(item)
    {
        I420VideoFrame* ptrOldestFrameInList =
            static_cast<I420VideoFrame*>(item->GetItem());
        if (ptrOldestFrameInList->render_time_ms() <=
            TickTime::MillisecondTimestamp() + _renderDelayMs)
        {
            if (ptrRenderFrame)
            {
                // List is traversed beginning to end. If ptrRenderFrame is not
                // NULL it must be the first, and thus oldest, VideoFrame in the
                // queue. It can be recycled.
                ReturnFrame(ptrRenderFrame);
                _incomingFrames.PopFront();
            }
            item = _incomingFrames.Next(item);
            ptrRenderFrame = ptrOldestFrameInList;
        }else
        {
            // All VideoFrames following this one will be even newer. No match
            // will be found.
            break;
        }
    }
    return ptrRenderFrame;
}

WebRtc_Word32 VideoFramesQueue::ReturnFrame(I420VideoFrame* ptrOldFrame)
{
    ptrOldFrame->set_timestamp(0);
    ptrOldFrame->set_width(0);
    ptrOldFrame->set_height(0);
    ptrOldFrame->set_render_time_ms(0);
    ptrOldFrame->ResetSize();
    _emptyFrames.PushBack(ptrOldFrame);
    return 0;
}

//
WebRtc_Word32 VideoFramesQueue::SetRenderDelay(WebRtc_UWord32 renderDelay)
{
     _renderDelayMs = renderDelay;
     return 0;
}
} // namespace webrtc
#endif // WEBRTC_MODULE_UTILITY_VIDEO