Re: Gstreamer and Transcode i.mx6

[Carlos Rafael Giani <dv@pseudoterminal.org>]

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On 2014-12-28 17:08, Carlos Rafael Giani wrote:
> On 2014-12-28 14:31, Peter Hafner wrote:
>> Hi,
>> I want to trans code 2 different types of streams to h264 codec, on a 
>> i.mx6 Dual.
>> First  stream is from a STK1160 video device
>> and I'm using this gstreamer commands.
>>
>> gst-launch-1.0 --gst-debug=3 v4l2src device=/dev/video0 ! 
>> videoconvert ! imxvpuenc_h264 bitrate=4096 ! 
>> "video/x-h264,stream-format=byte-stream,profile=high" ! h264parse ! 
>> matroskamux name=mux ! filesink location=output.FIFO -v
>>
>> This is working !
>>
>> The second stream, is a raw jpeg stream via udp.
>> This is the commands, I currently thought it is the best one:
>> gst-launch-1.0 --gst-debug=3 udpsrc buffer-size=1000000 port=5006 ! 
>> queue !  jpegdec ! videoconvert ! imxvpuenc_h264 bitrate=4096 ! 
>> "video/x-h264,stream-format=byte-stream,profile=high" ! h264parse ! 
>> matroskamux name=mux ! autovideosink
>>
>> I got always the error "reason not-negotited (-4). Of course tested a 
>> lot.
>>
>> This is working with video test src:
>> #gst-launch-1.0 videotestsrc !  videoconvert ! imxvpuenc_h264 
>> bitrate=4096 ! "video/x-h264,stream-format=byte-stream,profile=high" 
>> ! h264parse ! matroskamux name=mux ! filesink location=output.FIFO -v &
>> Thanks Peter
>>
>>
>
> With udpsrc, you need to define the caps for the output data 
> explicitely. Check out the "caps" property of udpsrc.
>
> Furthermore, you can replace jpegdec with imxvpudec (it can decode 
> motion JPEG). Once you do that, you can remove videoconvert from the 
> pipeline, since imxvpudec outputs I420-formatted pixels, which 
> imxvpuenc_h264 can use directly.
>
> Also, as a general advice, always try to use one of the transform 
> elements instead of videoconvert. The imx(g2d,ipu,pxp)videotransform 
> elements use hardware accelerated conversions, while videoconvert does 
> conversions with the CPU (and by default also does dithering, which is 
> even slower).
>
>

I just noticed another problem: the 
"video/x-h264,stream-format=byte-stream,profile=high" caps filter. You 
cannot use that, since the VPU encoder only supports the baseline 
profile. If that is ok, then simply remove this capsfilter.

Example pipeline:

gst-launch-1.0 --gst-debug=3 udpsrc buffer-size=1000000 port=5006 
caps="image/jpeg" ! queue !  imxvpudec ! imxvpuenc_h264 bitrate=4096 ! 
h264parse ! matroskamux name=mux ! autovideosink

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