[Elphel-support] Recording fullHD JP4 being limited to 7 seconds

flavio soares qazav3.0 at gmail.com
Thu Apr 26 00:32:11 PDT 2012


Hi, Andrey,

Sorry, I was rebooting, that's what kept me. Here is the result for
both cards (even though I can't really understand what it means):

[root at Elphel353 /root]3882# hdparm -I /dev/hdb

/dev/hdb:

ATA device, with non-removable media
	Model Number:        CF CARD 4GB
	Serial Number:             00003C2E
	Firmware Revision:
Standards:
	Likely used: 5
Configuration:
	Logical		max	current
	cylinders	8060	8060
	heads		16	16
	sectors/track	63	63
	--
	CHS current addressable sectors:    8124480
	LBA    user addressable sectors:    8124480
	device size with M = 1024*1024:        3967 MBytes
	device size with M = 1000*1000:        4159 MBytes (4 GB)
Capabilities:
	LBA, IORDY(may be)(cannot be disabled)
	bytes avail on r/w long: 4
	Queue depth: 1
	Standby timer values: spec'd by Vendor
	R/W multiple sector transfer: Max = 1	Current = 0
	DMA: mdma0 mdma1 *mdma2
		Cycle time: min=120ns recommended=120ns
	PIO: pio0 pio1 pio2 pio3 pio4
		Cycle time: no flow control=120ns  IORDY flow control=120ns
HW reset results:
	CBLID- below Vih
	Device num = 1
[root at Elphel353 /root]3882# hdparm -I /dev/hda

/dev/hda:

ATA device, with non-removable media
	Model Number:        CF CARD 4GB
	Serial Number:             00003C48
	Firmware Revision:
Standards:
	Likely used: 5
Configuration:
	Logical		max	current
	cylinders	8060	8060
	heads		16	16
	sectors/track	63	63
	--
	CHS current addressable sectors:    8124480
	LBA    user addressable sectors:    8124480
	device size with M = 1024*1024:        3967 MBytes
	device size with M = 1000*1000:        4159 MBytes (4 GB)
Capabilities:
	LBA, IORDY(may be)(cannot be disabled)
	bytes avail on r/w long: 4
	Queue depth: 1
	Standby timer values: spec'd by Vendor
	R/W multiple sector transfer: Max = 1	Current = 0
	DMA: mdma0 mdma1 *mdma2
		Cycle time: min=120ns recommended=120ns
	PIO: pio0 pio1 pio2 pio3 pio4
		Cycle time: no flow control=120ns  IORDY flow control=120ns
HW reset results:
	CBLID- below Vih
	Device num = 0


Thanks for the link, I'll check on it soon. I have a really good
graphic card here, but my Iceweasel is not up to the task =)  I'll
reboot and check it with chrome!

ps.: Do you think it's too dangerous to test the Sata the way I
mentioned? My computer is actually open at the moment with a Sata
literally hanging on it (backuping). =)

2012/4/26, Andrey Filippov <support-list at support.elphel.com>:
>>
>> Hello, Andrey, thanks for the quick response!
>>
> You are welcome , Flavio
>
>>
>> I'm also online (here it is 3:40am) =)
>>
>
> Not that late he - less than 1AM :-)
>
>>
>> My Kingston cards are not listed in the blacklist. Let's get them to
>> work and see how far they go. Here are the results of the tests, I'm
>> ssh-ed into the cam:
>>
>> [root at Elphel353 /mnt/0]944# time dd if=/dev/circbuf of=/dev/null
>> 38656+0 records in
>> 38656+0 records out
>> real    0m 0.42s
>> user    0m 0.03s
>> sys     0m 0.39s
>> [root at Elphel353 /mnt/0]944# time dd if=/dev/circbuf of=/dev/hdb1
>> 38656+0 records in
>> 38656+0 records out
>> real    0m 6.75s
>> user    0m 0.19s
>> sys     0m 2.46s
>> [root at Elphel353 /mnt/0]944#
>>
>> If I understood correctly, my card takes 6.75 seconds to write the
>> 19MB and 19 MB / 6.75 = 2.8MB/s should be the maximum data rate my
>> cards can handle, is that it?
>>
>
> Yes, the cards are in PIO mode so seem to be disabled. And as I wrote - it
> is not only that they are ~16/2.8 ~= 5.5 times slower than those in DMA
> mode, they use CPU much more during recording, so no resources fro other
> CPU tasks.
>
>  Can you try them with hdparm -I and send the reply? The CPU-limited
> recording rate in DMA mode should be ~16MB/s
>
>
>>
>> Meanwhile, I've tested normal HD JP4, at 720p and observed that
>> compression 100% is a killer, but at about 90%, the recording
>> proceeded without cutting the video, even tough the gui refresh rate
>> suffered.
>>
>
> Yes that is so - 90% is really good quality. It may also make sense to
> fine-tune coring value () in addition to JPEG quality to find the best
> overall quality/image size ratio.
>  With Eyesis we use 97-98%, but that is only because we use aberration
> correction by de-convolution that amplifies the noise and artifacts. BTW -
> here are our last panoramas made with the new camera (viewing requires good
> videocard and WebGL-capable browser)
> http://community.elphel.com/files/eyesis/pano-db-3/webgl_panorama_editor.html?kml=mainstreet_ro.kml&proto=mainstreet_ro.kml&ntxt=2&as_camera=95&start=result_1334548264_780764_1.jpeg&range=95&labels=false&keepzoom=false&closest2d=false&seethrough=0.4&transition=5&mask=&azimuth=23.2&elevation=-70.5&zoom=0.386&follow=false&mv3d=false
>
>
>>
>> ps.: I considered buying the Sundisk Extreme III, but I saw they were
>> not being sold at B&H at the moment. =/  If there is any other you
>> would recommend...
>>
>
> I'll ask here tomorrow, but I think recently we only used that card
> (different capacities)
>
> Andrey
>
>
>>
>> 2012/4/26, Andrey Filippov <support-list at support.elphel.com>:
>> > Hello Flavio,
>> >
>> > Most likely the problem is related to the CF - as I wrote in that old
>> > article, most CF cards in IDE mode lie about support of the DMA mode.
>> They
>> > do support UDMA so most people never notice that small lie. But Axis
>> > CPU
>> > used in the camera has a bug of it's own - and this bug is related to
>> > the
>> > UDMA. If the card would hostly report that it does not support DMA
>> > camera
>> > driver would just go to PIO mode (ABSOLUTELY NOT SUITABLE for the video
>> > recording - both slow and using to much of the camera CPU resources),
>> > but
>> > it does not, so camera may hang up and never come out of the boot
>> scripts.
>> > So what we did was to add some known "bad" cards to the driver black
>> list:
>> >
>> >
>> >
>> http://elphel.cvs.sourceforge.net/viewvc/elphel/elphel353-8.0/os/linux-2.6-tag--devboard-R2_10-4/drivers/ide/ide-dma.c?view=markup(lines
>> > 130..136).
>> >
>> > At some point we black-listed all no-name cards (we did not find any
>> among
>> > them that did support  DMA) You may use hdparm -I  (from
>> > http://192.168.0.9/phpshell.php, telnet or serial console that you
>> should
>> > have cable for) and the only way to re-enable (if you card matches the
>> > black-listed one) the card is to modify that file and recompile the
>> camera
>> > firmware. The only type of CF cards we use ourselves is "Sandisk
>> > Extreme
>> > III".
>> >
>> > When the card is blacklisted, camera bots correctly and is able to
>> > mount
>> > (and use) the card - it can be used to save images or very slow video
>> > (still useful for timelapse), but not the normal video.
>> >
>> > You may test the speed of the CF card (that test will destroy data on
>> it!)
>> > with the following command (again - phpshell, telnet, serial console):
>> >
>> > time dd if=/dev/circbuf of=/dev/hda #(or hdb - depending how is the
>> > card
>> > inserted/configured)
>> >
>> > /dev/circbuf is the circular buffer ~19MB in size that is very fast to
>> read
>> > for the camera, so the speed will be related to the CF itself
>> >
>> > You may try it on /dev/null first:
>> >
>> > [root at Goniometer /dev]16713# time dd if=/dev/circbuf of=/dev/null
>> > 38656+0 records in
>> > 38656+0 records out
>> > real    0m 0.43s
>> > user    0m 0.11s
>> > sys     0m 0.32s
>> >
>> > With phpshell you may just open the following link (provided you have
>> > the
>> > default IP) - just replace all spaces in the command line with "+"
>> > signs
>> >
>> http://192.168.0.9/phpshell.php?command=time+dd+if=/dev/circbuf+of=/dev/null
>> >
>> > Then divide 19MB by the time measured.
>> >
>> > Andrey
>> >
>>
>> _______________________________________________
>> Support-list mailing list
>> Support-list at support.elphel.com
>> http://support.elphel.com/mailman/listinfo/support-list_support.elphel.com
>>
>




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