Dropping Audio Samples, Downstream Can't Keep Up

[Dimitrios Katsaros]

The videorate element doesn't change the rate at which the hardware is
capturing, so my guess is that it has something to do with that. It is
possible that the muxer was being stalled which in turn would fill the
audio pipeline and would eventually lead to sample loss on a live source.
However I am not experienced with the windows elements so I can only
speculate. One thing you may want to test is adding an audio rate in the
pipeline with the videorate. Another would be to check what the actual
framerate with the higher exposure is and setting the pipeline with that
framerate rather than 30. The muxer may be expecting frames at the target
rate but the source can't report that it can capture at a lower rate,
leading to the audio piepline being stalled.

Dimitrios

On Fri, Jan 13, 2017 at 9:14 AM, Brendan Lockhart <somedude114 at gmail.com>
wrote:

> Turns out what was happening is that the exposure on the webcam was too
> high. Lowering the exposure increased the framerate and fixed the warning.
> That's strange, because it was happening even if I put a videorate element
> after the ksvideosrc.
>
> Is this because ksvideosrc was producing bad timestamps? Is there a way
> that I can check that hypothesis?
>
> On Thu, Jan 12, 2017 at 2:29 AM, Brendan Lockhart <somedude114 at gmail.com>
> wrote:
>
>> Hello all,
>>
>> I'm having an issue where when streaming video/audio with the pipeline:
>>
>> gst-launch-1.0 ksvideosrc device-index=0 ! image/jpeg,width=1024,height=768,framerate=30/1
>>> ! queue ! jpegparse ! jpegdec ! queue ! x264enc tune=zerolatency
>>> speed-preset=veryfast bitrate=4096 ! h264parse ! video/x-h264, profile=high
>>> ! queue ! flvmux streamable=true name=mux ! queue ! rtmpsink
>>> location=rtmp://<my-url> autoaudiosrc ! audio/x-raw ! queue ! audioconvert
>>> ! avenc_aac ! aacparse ! queue ! mux.
>>
>>
>> I eventually start generating errors:
>>
>>   gst_audio_base_src_create (): /GstPipeline:pipeline0/GstAuto
>>> AudioSrc:autoaudiosrc0/GstDirectSoundSrc:autoaudiosrc0-
>>> actual-src-directsoun:
>>> Dropped 1420020 samples. This is most likely because downstream can't
>>> keep up and is consuming samples too slowly.
>>
>>
>>  With this pipeline, my PC is at ~8% CPU utilization so I don't think
>> it's because my PC isn't powerful enough.
>>
>> I know this error has been brought up in the past, but unfortunately none
>> of the proposed solutions seem to be fixing this problem. Does anyone have
>> any insight as to what might be causing this error?
>>
>
>
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