Re: [Linphone-developers] Distorted Image using VPU encoder

[Wu Xing]

I do believe there are some problems with my codes. 

I only tested it with X-Lite, two way video calling is OK(Both the MX27 and PC's X-Lite can display image, but I remembered the display quality was bad).

I have two MX27 and I ran the Mediastreamer's test program 'mediastream' in both sides yesterday and it failed to display clearly, the image was a mess.

My teammates are working on it now...

On Fri, Aug 7, 2009 at 7:23 PM, Code Warrior <address@hidden> wrote:

Hi,

I've been thinking to integrate the VPU directly under medistreamer bypassing the ffmpeg. Your code really helped.
Many thanks for helping me out.

I'm still not able to display the received video at iMX27 even though the output from the board (video in the other direction) is correctly decoded and displayed by the Linphone running on my laptop (Windows version). [BTW, i did few changes in your videodec.c to enable videoout]. Did you try two way video calling ? What version of linphone, ffmpeg and vpu are you using ??

FYI. I'm getting a lot of error traces in the decode routine of Linphone (imX27). It says "Prescale Enable. not enough bs data".
But if i see the captured RTP packets, there is sufficient data in the frames. Marker bit is set as well (though it is not as consistent
across the frames as is sent by iMX27).

thanks
/csj

On Fri, Aug 7, 2009 at 7:08 AM, Wu Xing <address@hidden> wrote:

Hi,

Glad to find some other one using i.MX27 here!

I've integrated the i.MX27's VPU code with Mediastreamer-2.1.0, using H.263 encoding, too.

I modified the videoenc.c and videodec.c, but i didn't meet the problem you said, it seemed to work fine with X-Lite.

I didn't know much about how YUV encoder works, so I just simply imitated the mxc_vpu_test code.

videoenc.c and videodec.c are attached here, hope they helps.

On Thu, Aug 6, 2009 at 11:01 PM, Code Warrior <address@hidden> wrote:

Hi,

I'm running Linphone 3.1.2 over i.MX27 platform using VPU encoder (H.263 encoding). I've
integrated the VPU code with Linphone and have been able to get two way video. Problem is
the encoded video is distorted. Investigating more into the issue, i could find that all the I-frames
are displayed correctly but the following P-frames keep getting shifted towards the left. This corrupts the
whole running video. I forced the VPU to send all the I-frames and it worked. Clearly, there seems to be
some issue with encoding of P-frames. YUV image (captured image fed to the encoder) is perfect
and is displayed correctly. So no issue in the captured image as well.

Looks to me some issue with the VPU encoder parameters. While i'm investigating it, any help in this regards
would be appreciated. Has anyone encountered this issue earlier ?

thanks
/csj

Note: I know this is not an iMX forum. But i thought i could get some help here since it is related to Linphone.

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