[gst-devel] Problems with clockoverlay and MJPEG stream

Mon Oct 6 06:52:58 CEST 2008

Hi Noe ,
             As you are using decodebin here as a decoder element so what is
does is on the basis of input file it selects the decoder , here in your
case it is selecting jpegdec(see red line in your log) , that means it will
decode only one frame of data .
            To fix this problem you can use ffdec_mjpeg element which is
there in ffmpeg package.

On Sat, Oct 4, 2008 at 6:06 AM, Noe Nieto <tzicatl at gmail.com> wrote:

> Thanks Sudarshan
>
> Now I've changed the pipeline to this:
> gst-launch-0.10 -v gnomevfssrc location=$CAMERA ! decodebin ! clockoverlay
> text="Camera 1" ! ffmpegcolorspace !  videoscale !  ximagesink
> force-aspect-ratio="true"
>
> But when I run the pipeline there is no video, it's only an still image
> with the clock time overlaid, but it is not moving.
>
> What is the problem? I have reviewed the output of gst-launch and I found a
> strange warning:
>
>
> Setting pipeline to PAUSED ...
> Pipeline is PREROLLING ...
> /pipeline0/decodebin0/typefind.src: caps = multipart/x-mixed-replace
> /pipeline0/decodebin0/multipartdemux0.sink: caps =
> multipart/x-mixed-replace
> /pipeline0/decodebin0/jpegdec0.sink: caps = image/jpeg
> /pipeline0/decodebin0/jpegdec0.src: caps = video/x-raw-yuv,
> format=(fourcc)I420, width=(int)640, height=(int)480,
> framerate=(fraction)0/1
> /pipeline0/clockoverlay0.src: caps = video/x-raw-yuv, format=(fourcc)I420,
> width=(int)640, height=(int)480, framerate=(fraction)0/1
> /pipeline0/clockoverlay0.video_sink: caps = video/x-raw-yuv,
> format=(fourcc)I420, width=(int)640, height=(int)480,
> framerate=(fraction)0/1
> /pipeline0/decodebin0.src0: caps = video/x-raw-yuv, format=(fourcc)I420,
> width=(int)640, height=(int)480, framerate=(fraction)0/1
> /pipeline0/decodebin0.src0.proxypad1: caps = video/x-raw-yuv,
> format=(fourcc)I420, width=(int)640, height=(int)480,
> framerate=(fraction)0/1
>
> (gst-launch-0.10:9349): GStreamer-CRITICAL **: gst_util_uint64_scale_int:
> assertion `denom > 0' failed
> /pipeline0/ffmpegcsp0.src: caps = video/x-raw-rgb, bpp=(int)32,
> depth=(int)24, endianness=(int)4321, red_mask=(int)65280,
> green_mask=(int)16711680, blue_mask=(int)-16777216, width=(int)640,
> height=(int)480, framerate=(fraction)0/1, pixel-aspect-ratio=(fraction)1/1
> /pipeline0/ffmpegcsp0.sink: caps = video/x-raw-yuv, format=(fourcc)I420,
> width=(int)640, height=(int)480, framerate=(fraction)0/1
> /pipeline0/videoscale0.src: caps = video/x-raw-rgb, bpp=(int)32,
> depth=(int)24, endianness=(int)4321, red_mask=(int)65280,
> green_mask=(int)16711680, blue_mask=(int)-16777216, width=(int)640,
> height=(int)480, framerate=(fraction)0/1, pixel-aspect-ratio=(fraction)1/1
> /pipeline0/videoscale0.sink: caps = video/x-raw-rgb, bpp=(int)32,
> depth=(int)24, endianness=(int)4321, red_mask=(int)65280,
> green_mask=(int)16711680, blue_mask=(int)-16777216, width=(int)640,
> height=(int)480, framerate=(fraction)0/1, pixel-aspect-ratio=(fraction)1/1
> /pipeline0/ximagesink0.sink: caps = video/x-raw-rgb, bpp=(int)32,
> depth=(int)24, endianness=(int)4321, red_mask=(int)65280,
> green_mask=(int)16711680, blue_mask=(int)-16777216, width=(int)640,
> height=(int)480, framerate=(fraction)0/1, pixel-aspect-ratio=(fraction)1/1
> Pipeline is PREROLLED ...
> Setting pipeline to PLAYING ...
> New clock: GstSystemClock
> Caught interrupt -- handling interrupt.
> Interrupt: Setting pipeline to PAUSED ...
> Execution ended after 8957877000 ns.
> Setting pipeline to PAUSED ...
> Setting pipeline to READY ...
> /pipeline0/ximagesink0.sink: caps = NULL
> /pipeline0/videoscale0.src: caps = NULL
> /pipeline0/videoscale0.sink: caps = NULL
> /pipeline0/ffmpegcsp0.src: caps = NULL
> /pipeline0/ffmpegcsp0.sink: caps = NULL
> /pipeline0/clockoverlay0.src: caps = NULL
> /pipeline0/clockoverlay0.video_sink: caps = NULL
> /pipeline0/decodebin0.src0: caps = NULL
> /pipeline0/decodebin0/jpegdec0.src: caps = NULL
> /pipeline0/decodebin0/jpegdec0.sink: caps = NULL
> /pipeline0/decodebin0/multipartdemux0.src_0: caps = NULL
> /pipeline0/decodebin0/multipartdemux0.sink: caps = NULL
> /pipeline0/decodebin0/typefind.src: caps = NULL
> Setting pipeline to NULL ...
> X connection to :0.0 broken (explicit kill or server shutdown).
>
> Is there a work around this, or a typical problem?
>
> Thank you.
>
> 2008/10/2 sudarshan bisht <bisht.sudarshan at gmail.com>
>
>  Hi Noe ,
>>
>>      Your problem is because clockoverlay element works on YUV 4:2:0 data
>> ( see caps by doing gst-inspect clockoverlay ) that means it expects YUV
>> 4:2:0 data from previous element and sends YUV 4:2:0 data also to next
>> element .  But ximagesink works on RGB data thats why you can't connect
>> these tow elements .
>>    To solve this problem insert clockoverlay just after decodbin element
>> .
>>
>>
>>   On Thu, Oct 2, 2008 at 12:37 AM, Noe Nieto <tzicatl at gmail.com> wrote:
>>
>>>   Hi, I had posted this topic before but I am unsure if it reached the
>>> mailing list.
>>>
>>> I have an app that displays MJPEG Streams from webcam cameras that looks
>>> like the following:
>>>
>>> gst-launch-0.10 gnomevfssrc location="http://ip/image?speed=25" !
>>> decodebin ! ffmpegcolorspace ! videoscale ! ximagesink
>>> force-aspect-ratio="true"
>>>
>>> But when I add a clockoverlay element between the videoscale and
>>> ximagesink, the video gets frozen. Looks like it just displays the first
>>> frame.
>>>
>>> Can someone please, help me? What I am doing wrong.
>>>
>>> Noe Nieto.
>>>
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>>
>>
>> --
>> Regards,
>>
>> Sudarshan Bisht
>>
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>
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-- 
Regards,

Sudarshan Bisht
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