On Sat, 2011-03-12 at 09:30 -0800, Dirk Beer wrote: > On Tue, Mar 8, 2011 at 8:44 PM, Dirk Beer <[email protected]> wrote: > > I'm having problems with image quality with ivtvfb kernel module. > > I did some more troubleshooting, and it looks like the problem is with > ivtv and the S-Video output. > > dd if=/dev/video0 of=test.mpg > > looks good. > > dd if=/dev/video0 of=/dev/video16 bs=64k > > looks bad on S-Video 1: grainy and desaturated color. > but good on Composite 1.
The PVR-350 defaults to outputting on both CVBS and S-Video. Could you test with v4l2-ctl to set the output explciitly to S-Video only? > I'm using: > * kernel 2.6.26-ARCH i686 (old because the Arch-based LinHES R6 uses > only that kernel) > * PVR-350 > * recommended firmware from ivtvdriver.org > * S-video 1 output or Composite 1 output > > This identical hardware (including cables, tv, etc) gave me a nice > picture recently, so I don't think it is hardware related. Please try and test these things if you can (maybe you already have): 1. The PVR-350 S-Video output quality using Windows 2. A different S-Video receiving device (another TV, VCR, or even a PVR-150) 3. A different S-Video cable Most PVR-350's are getting old, so a partial failure of the SAA7129 chip due to age would not be surprising. If you look at page 47 of the SAA7129 datasheet: http://dl.ivtvdriver.org/datasheets/video/SAA7128H_SAA7129H_3.pdf it is possible for the DAC and output amplifier for CVBS to be fine, while the DAC and output amplifier for C is failing. > I can use Composite for now, but would like to use S-Video since it > normally has slightly better video quality. Does anyone have any > suggestions of how to fix S-Video? The SAA7129 isn't a terribly complicated chip, so if you really do beleive it is just a register being set wrong, you can examine and twiddle the registers of the SAA7129 yourself using v4l2-dbg. (Your ivtv & saa7127 modules, and mabye other core videodev and v4l2 related modules, will need to be built with the CONFIG_VIDEO_ADV_DEBUG kernel configuration option for v4l2-dbg to work.) The registers of the SAA7129 are documented on pages 15-35 of the datasheet. A simple register to play with, to get an obvious effect, is register 0x3a, where the state of bit 7 controls whether the SAA7129 displays normal video or a color bar pattern. I'm really busy for the next 2 weeks, so I won't be able to look into any possible problem myself until then. Even then I'll have to jump through hoops to get a device that can receive S-Video near my PVR-350. Regards, Andy > Dirk > > ----------------------------------------- > [root@obmyth ~]# dmesg|grep ivtv > ivtv: Start initialization, version 1.4.0 > ivtv0: Initializing card #0 > ivtv0: Autodetected Hauppauge card (cx23415 based) > ivtv 0000:01:06.0: PCI INT A -> Link[APC3] -> GSI 18 (level, high) -> IRQ 18 > ivtv0: Unreasonably low latency timer, setting to 64 (was 32) > ivtv0: Autodetected Hauppauge WinTV PVR-350 > saa7115 2-0021: saa7115 found (1f7115d0e100000) @ 0x42 (ivtv i2c driver #0) > saa7127 2-0044: saa7129 found @ 0x88 (ivtv i2c driver #0) > msp3400 2-0040: MSP4448G-A2 found @ 0x80 (ivtv i2c driver #0) > tuner 2-0043: chip found @ 0x86 (ivtv i2c driver #0) > tuner 2-0061: chip found @ 0xc2 (ivtv i2c driver #0) > ivtv0: Registered device video0 for encoder MPG (4096 kB) > ivtv0: Registered device video32 for encoder YUV (2048 kB) > ivtv0: Registered device vbi0 for encoder VBI (1024 kB) > ivtv0: Registered device video24 for encoder PCM (320 kB) > ivtv0: Registered device radio0 for encoder radio > ivtv0: Registered device video16 for decoder MPG (1024 kB) > ivtv0: Registered device vbi8 for decoder VBI (64 kB) > ivtv0: Registered device vbi16 for decoder VOUT > ivtv0: Registered device video48 for decoder YUV (1024 kB) > ivtv0: Initialized card #0: Hauppauge WinTV PVR-350 > ivtv: End initialization > ivtv 0000:01:06.0: firmware: requesting v4l-cx2341x-enc.fw > ivtv0: Loaded v4l-cx2341x-enc.fw firmware (376836 bytes) > ivtv 0000:01:06.0: firmware: requesting v4l-cx2341x-dec.fw > ivtv0: Loaded v4l-cx2341x-dec.fw firmware (262144 bytes) > ivtv0: Encoder revision: 0x02060039 > ivtv0: Decoder revision: 0x02020023 > ivtv 0000:01:06.0: firmware: requesting v4l-cx2341x-init.mpg > ivtv0: Loaded v4l-cx2341x-init.mpg firmware (155648 bytes) > > _______________________________________________ > ivtv-users mailing list > [email protected] > http://ivtvdriver.org/mailman/listinfo/ivtv-users _______________________________________________ ivtv-users mailing list [email protected] http://ivtvdriver.org/mailman/listinfo/ivtv-users
