Make RGB LED Display with xc-3 kit more Economical

[jsmaia]

Hi,
At first I am not thinking to connect the modules in a daysy chain. I am thinking to use a L1 I/O pin for each 16x8 module data signal plus 6 others I/O pins for A, B, C, latch, clk and gclk common for all the modules. For 48x48 big modules we will need 18 16x8 modules (a total of 24 I/O pins = 18 data + 1 A + 1 B + 1 C + 1 clk + 1 latch + 1 gclk). We can use a 64 pins L1 wich has 36 I/O pins.
What do you think about that?
Regards,
Maia

[jagspaul]

for 18 module 18 individual data bus (1 bit). So that means you are sending RGB data through a single data pin. I cunt understand the benefit of this hardware. But I prefer daisy chain. I think you should think over this once again.

jags

[jagspaul]

Issue : Video sender system (mplayer)

It is very important issue as with out a good sender system LED tile is useless. Now we have a ready video sender application (mplayer with xudp) made by xmos team. And I am making a simple GUI (C# based) to operate mplayer. Though one of my friend suggested VLC instead of mplayer but due to my lack of knowledge to customize VLC over xudp for LED Tile I forced to use mplayer as it is pre customize for our LED tile. But now the issue is that the mplayer can support upto 330 X 256 LED tile. Beyond this mplayer get ceased.

Note:
I am simulating the video on a single Ethernet LED Tile board. The mplayer command as follows.

Code: Select all

mplayer -vf scale=330:256 -autosync 30 -loop 0 -vo xudp:noinit:tilewidth=330:tileheight=256 test2.wmv 

How to send large size video over UDP? Can VLC solve this issue? I heard that VLC has option to send video over UDP and it can handle large size. If it is true can it possible to customize this feature to send video to our LED Tile board?

jags

[jsmaia]

Hi Jags,
Did you try using smaler tiles? There a example on a document from XMOS where they use:

tilewidth=32:tileheight=32:chainstart=3_2:chainpoint=0_2:chainstart=3_3:chainpoint=0_3:chainstart=3_0:chainpoint=0_0:chainpoint=0_1:chainpoint=3_1 c:\VIDEOFILE.AVI

This way smaller tiles are linked side by side. I think 330x256 is really big for each tile. And 330 is not a multiple of 8. Don´t know if has to be, but you can check it.

Regards,
Maia

[jagspaul]

Hi Maia,

It will be 336 X 256.

Though I am sending video as single tile but physically it is multiple tile. To make cost effective I am linking multiple tile with xlinks instead Ethernet chain (discussed in forum) . In the starting of chain there is a Ethernet card which is getting total frame from mplayer and splitting and sending small frame to proper tile board through xlinks. Each tile board is made by a single L1 chip and can drive maximum 6K pixel (SW PWM) & 12K pixel (HW PWM).

Please note that my single L1 based LED tile control board is not ready I am just simulating it on Ethernet board.

I think there is no difference in data throughput for sending small multiple tile and large single tile of mplayer.

I think there is some issue in xudp source (made by xmos team). We need to debug this.

But it is very sad that I could not able to build mplayer on windows machine using mingw.

Can any body help?

jags

[jagspaul]

Today I have checked streaming video over UDP with VLC but not found expected result. The result is good up to 256 pixel video, beyond this lot of frame droop and noisy picture found.

I have installed VLC in two computer connected with GBPS LAN. In PC “A” I streamed out the video over UDP and in PC “B” video is played on streamed in UDP.

I am very much upset to see the result. Why VLC is not able to play large video over UDP? What is wrong I am doing?

Can any body guide me to solve this?

I need to play (stream out) large video over UDP (Raw RGB data) for large LED tile display.

jags

[jagspaul]

Thanks Maia, I think you are right. There is a limitation in mplayer xudp source. Maximum tile width limited to 342 pixel and no limit on tile height. So large video can be send with multiple tile and maximum tile width not exit 342 pixel.

Code: Select all

 #define PIXELS_PER_PACKET 342

typedef struct {
	uint32_t magic;
	uint16_t identifier;
	uint16_t tilewidth;
	uint16_t tileheight;
	uint16_t segid;
	uint16_t pixptr;
	uint16_t datalen;
	uint16_t dummy;
	unsigned char data[PIXELS_PER_PACKET * 3];
} xudp_packet_t;

I tried and successfully build mplayer source on linux machine as I couldn’t able to build mplayer source on windows.
After debugging I found the above logic. As my LED tile hardware is different than original XMOS tile so it is required to modify the xudp source according to my hardware.

Can anybody give some clue??

@Maia, thanks once again for your clue.
What is your progress for LED Tile project??

Regards
jags

[jsmaia]

Hi Jags,
I also tried to use VLC player instead of mplayer to stream video over UDP but soon I realized that the data on the packerts have to carry some informations needed by XL-1 software like the "magic word" XMOS. So I don´t think it´s possible.
I am not a UDP expert but I think this limitation is per packet as we usualy cannot send more than 1500 bytes (MTU). So the XMOS engineers limited the packet size on about 1200 bytes. The video data can be splited in many packets so I think it´s not the problem.
Sorry, my English is not good. If you cannot undestand what I trying to say I can try again using other words.
Regards,
Maia

[jagspaul]

Hi Maia,
Sorry for late answer. Actually without customization neither mplayer nor vlc can send video to XMOS LED tile controller. Mplayer has been customize with xudp patch to make compatible with LED tile. So vlc can be used with LED tile after proper customizing.

However I am modifying mplayer xudp patch as per my need. But still I am missing an important feature in mplayer. I need to echo the video locally (on PC monitor) while sending same at LED tile.

Have you any idea to solve it?

jags

[jsmaia]

Hi,
First test of the LED board showing a static image. The photo quality is not good because I took it from my cell phone. I am using a LCP1114 to generate the signals. The colors and intensity are very good.
Next step: play some animations.
Regards,
Maia

placa_teste_1.jpg