rdpsnd: implement buffer overrun detection.

diff --git a/channels/rdpsnd/client/rdpsnd_main.c b/channels/rdpsnd/client/rdpsnd_main.c
index 510572c..8b11e1c 100644 (file)
--- a/channels/rdpsnd/client/rdpsnd_main.c
+++ b/channels/rdpsnd/client/rdpsnd_main.c
@@ -86,6 +86,9 @@ struct rdpsnd_plugin
        BOOL isOpen;
        AUDIO_FORMAT* fixed_format;
 
+       UINT32 startPlayTime;
+       size_t totalPlaySize;
+
        char* subsystem;
        char* device_name;
 
@@ -370,6 +373,8 @@ static BOOL rdpsnd_ensure_device_is_open(rdpsndPlugin* rdpsnd, UINT32 wFormatNo,
 
                rdpsnd->isOpen = TRUE;
                rdpsnd->wCurrentFormatNo = wFormatNo;
+               rdpsnd->startPlayTime = 0;
+               rdpsnd->totalPlaySize = 0;
        }
 
        return TRUE;
@@ -437,6 +442,54 @@ static UINT rdpsnd_send_wave_confirm_pdu(rdpsndPlugin* rdpsnd, UINT16 wTimeStamp
        return rdpsnd_virtual_channel_write(rdpsnd, pdu);
 }
 
+static BOOL rdpsnd_detect_overrun(rdpsndPlugin* rdpsnd, AUDIO_FORMAT* format, size_t size)
+{
+       UINT32 bpf;
+       UINT32 now;
+       UINT32 duration;
+       UINT32 totalDuration;
+       UINT32 remainingDuration;
+       UINT32 maxDuration;
+
+       bpf = format->nChannels * format->wBitsPerSample / 8;
+       duration = (UINT32)(1000 * size / bpf / format->nSamplesPerSec);
+       totalDuration = (UINT32)(1000 * rdpsnd->totalPlaySize / bpf / format->nSamplesPerSec);
+       now = GetTickCountPrecise();
+       if (rdpsnd->startPlayTime == 0)
+       {
+               rdpsnd->startPlayTime = now;
+               rdpsnd->totalPlaySize = size;
+               return FALSE;
+       }
+       else if (now - rdpsnd->startPlayTime > totalDuration + 10)
+       {
+               /* Buffer underrun */
+               WLog_Print(rdpsnd->log, WLOG_DEBUG, "Buffer underrun by %u ms",
+                          (UINT)(now - rdpsnd->startPlayTime - totalDuration));
+               rdpsnd->startPlayTime = now;
+               rdpsnd->totalPlaySize = size;
+               return FALSE;
+       }
+       else
+       {
+               /* Calculate remaining duration to be played */
+               remainingDuration = totalDuration - (now - rdpsnd->startPlayTime);
+
+               /* Maximum allow duration calculation */
+               maxDuration = duration * 2 + rdpsnd->latency;
+
+               if (remainingDuration + duration > maxDuration)
+               {
+                       WLog_Print(rdpsnd->log, WLOG_DEBUG, "Buffer overrun pending %u ms dropping %u ms",
+                                  remainingDuration, duration);
+                       return TRUE;
+               }
+
+               rdpsnd->totalPlaySize += size;
+               return FALSE;
+       }
+}
+
 static UINT rdpsnd_treat_wave(rdpsndPlugin* rdpsnd, wStream* s, size_t size)
 {
        BYTE* data;
@@ -454,7 +507,7 @@ static UINT rdpsnd_treat_wave(rdpsndPlugin* rdpsnd, wStream* s, size_t size)
                   "Wave: cBlockNo: %" PRIu8 " wTimeStamp: %" PRIu16 ", size: %" PRIdz,
                   rdpsnd->cBlockNo, rdpsnd->wTimeStamp, size);
 
-       if (rdpsnd->device && rdpsnd->attached)
+       if (rdpsnd->device && rdpsnd->attached && !rdpsnd_detect_overrun(rdpsnd, format, size))
        {
                UINT status = CHANNEL_RC_OK;
                wStream* pcmData = StreamPool_Take(rdpsnd->pool, 4096);