[gst-devel] Black-and-white output

Sun May 16 08:24:04 CEST 2010

Hi,

On Sat, May 15, 2010 at 10:24 PM, Louis-Simon Houde <houdelou at hotmail.com>wrote:

>  Thank you.
>
> I will remove the first two ffmpegcolorspace. At least I find a solution to
> get it working (changing Ubuntu version) even if it is not the ideal
> solution. From what you understand, do you think it is more of a gstreamer
> or ubuntu bug ? I would guess it is related to Ubuntu because gstreamer
> version is 0.10 on both Ubuntu version.
>

event though the most significant version numbers are the same, the minor
has changed. Many things may change between one (minor) release and the
other.

Given that the following pipeline works as expected (explicit color space
format):

gst-launch-0.10 -v  \
  input1. ! queue ! videoscale ! video/x-raw-yuv,width=320,height=240 !
videobox right=-340 ! ffmpegcolorspace !
"video/x-raw-yuv,format=(fourcc)AYUV" ! vmix.sink_0 \
  input2. ! queue ! videoscale ! ffmpegcolorspace ! "video/x-raw-yuv,
format=(fourcc)AYUV,width=320,height=240" ! vmix.sink_1 \
  vmix. ! ffmpegcolorspace ! ffenc_flv ! ffmux_flv ! filesink
location='test.flv' \
  videotestsrc name='input1' num-buffers=100 \
  videotestsrc name='input2' num-buffers=100 \
  videomixer name=vmix background=black sink_0::xpos=0 sink_0::ypos=0
sink_0::zorder=0 sink_1::xpos=340 sink_1::ypos=0 sink_1::zorder=1

I'd say the "regression" has been caused by some changes in the caps
negotiation. Not being in direct touch with the code I cannot say whether
this is a feature or a bug, but I'd suggest you to file anyway a bug to
GStreamer Bugzilla and then let a more authoritative developer speak, (s)he
may even mark it as INVALID, but a proper explanation for the reasons will
be given.

Regards

>
> ------------------------------
> Date: Sat, 15 May 2010 21:42:02 +0300
>
> From: gibrovacco at gmail.com
> To: gstreamer-devel at lists.sourceforge.net
> Subject: Re: [gst-devel] Black-and-white output
>
> Hi,
>
> On Sat, May 15, 2010 at 8:57 PM, Louis-Simon Houde <houdelou at hotmail.com>wrote:
>
>  Thanks for you reply,
>
> Finally, I managed to find a solution, not the least invasive though : I switched from Ubuntu 10.04 to 9.10. And now, with the same command, the color is showing. Because I'm on Amazon EC2, I can switch server pretty quickly. So, on 8.04, it was freezing at "System Clock" step, on 10.04 no color and fine on 9.10 and 9.04. So I guess it is an Ubuntu Issue ? Or the 9.04 and 9.10 versions are more forgiving.
>
> Here is the big command :
>
> gst-launch-0.10 -v input1. ! queue ! decodebin2 ! videoscale ! video/x-raw-yuv,width=320,height=240 ! videobox right=-340 ! ffmpegcolorspace ! vmix.sink_0 input2. ! queue ! decodebin2 ! ffmpegcolorspace ! videoscale ! video/x-raw-yuv,width=320,height=240 ! vmix.sink_1 vmix. ! ffmpegcolorspace ! ffenc_flv ! ffmux_flv ! filesink location='/mnt/data/home/karaoke/www/karaoke/output/test.flv' filesrc name='input1' location=/mnt/data/home/karaoke/smartfox/SFS_PRO_1.6.6/Server/RedBox/webapps/SFS_RedBox/streams/SmartVideoClipPlayer_IronMan.flv filesrc name='input2' location=/mnt/data/home/karaoke/smartfox/SFS_PRO_1.6.6/Server/RedBox/webapps/SFS_RedBox/streams/SmartVideoClipPlayer_TheDarkKnight.flv videomixer name=vmix background=black sink_0::xpos=0 sink_0::ypos=0 sink_0::zorder=0 sink_1::xpos=340 sink_1::ypos=0 sink_1::zorder=1
>
> The point of this command I think is to show two different movie in one stream. But I must say I just copied the line from our media expert :)
>
> looks like the first two ffmpegcolorspace elements are converting the
> images to grayscale. As they're unneeded (you're already specifying the
> color space in the previous caps) you can safely remove them. I modified
> your pipeline for my tests as follows:
>
> gst-launch-0.10 -v  \
>   input1. ! queue ! videoscale ! video/x-raw-yuv,width=320,height=240 !
> videobox right=-340 ! ffmpegcolorspace ! vmix.sink_0 \
>   input2. ! queue ! ffmpegcolorspace ! videoscale !
> video/x-raw-yuv,width=320,height=240 ! vmix.sink_1 \
>   vmix. ! ffmpegcolorspace ! ffenc_flv ! ffmux_flv ! filesink
> location='test.flv' \
>   videotestsrc name='input1' num-buffers=100 \
>   videotestsrc name='input2' num-buffers=100 \
>   videomixer name=vmix background=black sink_0::xpos=0 sink_0::ypos=0
> sink_0::zorder=0 sink_1::xpos=340 sink_1::ypos=0 sink_1::zorder=1
>
> the effect on the output file is the same as you described. Removing the
> first two color space converters (unneeded AFAIK):
>
> gst-launch-0.10 -v  \
>   input1. ! queue ! videoscale ! video/x-raw-yuv,width=320,height=240 !
> videobox right=-340 ! vmix.sink_0 \
>   input2. ! queue ! videoscale ! video/x-raw-yuv,width=320,height=240 !
> vmix.sink_1 \
>   vmix. ! ffmpegcolorspace ! ffenc_flv ! ffmux_flv ! filesink
> location='test.flv' \
>   videotestsrc name='input1' num-buffers=100 \
>   videotestsrc name='input2' num-buffers=100 \
>   videomixer name=vmix background=black sink_0::xpos=0 sink_0::ypos=0
> sink_0::zorder=0 sink_1::xpos=340 sink_1::ypos=0 sink_1::zorder=1
>
> it works nicely. It remains to understand why the color space converters
> are defaulting to grayscale :\.
>
> Regards.
>
>
>
> Thanks !
>
> ------------------------------
> Date: Sat, 15 May 2010 09:44:04 +0300
> From: gibrovacco at gmail.com
> To: gstreamer-devel at lists.sourceforge.net
> Subject: Re: [gst-devel] Black-and-white output
>
>
> Hi,
>
> On Wed, May 12, 2010 at 7:11 PM, Louis-Simon Houde <houdelou at hotmail.com>wrote:
>
>  Hello,
>
> The question might sound completely silly for you but does gstreamer needs
> a video card to generate video output on command line with its gst-launch
> command ?
>
>
> it shouldn't matter as long as you're not rendering the output on the card
> itself.. can you please post the gst-launch command you're using?
>
> Regards
>
>
>
> I'm asking this question because we use gst-launch to generate video
> output. On one of the server, with identical command, the output is
> black-and-white. One of the server doesn't have any video card because it is
> hosted on Amazon EC2.
>
> Ubuntu versions are different also so it might be another cue. But it is
> the same gstreamer version on both servers.
>
> Thanks
>
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