Cropping with Hauppauge HVR-1900
Hello,
I have a Hauppauge HVR-1900 which works fine with the pvrusb2 driver. However because most TV channels now air with 16:9 content inside 4:3 images, I would like to crop out the top and bottom black bars before encoding via the hardware MPEG2 encoder. I tried using the ctl_crop_top and ctl_crop_height in /sysfs as well as the --set-crop option of v4l2-ctrl but only received error messages indicating a value out of range.
The card has a cx25843 which should support cropping. Does anyone know how to get this feature to work ?
Thanks in advance for the help,
Joseph
Quoted 9 lines · jmdk
Hello,
I have a Hauppauge HVR-1900 which works fine with the pvrusb2 driver. However because most TV channels now air with 16:9 content inside 4:3 images, I would like to crop out the top and bottom black bars before encoding via the hardware MPEG2 encoder. I tried using the
ctl_crop_topandctl_crop_heightin /sysfs as well as the --set-crop option of v4l2-ctrl but only received error messages indicating a value out of range.
Quoted 4 lines
The card has a cx25843 which should support cropping. Does anyone know how to get this feature to work ?
Thanks in advance for the help,
Unfortunately the cx25840 driver does not implement any cropping capability and the recent change to the v4l-subdevice architecture currently lacks the API entrypoints to make such a thing possible :-(
A pvrusb2 user a while back (it's in the pvrusb2 list archives) came up with some patches to the cx25840 driver that implement cropping. He also generated corresponding patches for the pvrusb2 driver. I merged his pvrusb2 patches (which is why you see that support in the driver) but not the cx25840 patches since I'm not an expert on that chip and I don't have the ability to verify that the patches preserve correct behavior for all the other devices that use the same chip. I did pass the cx25840 patches to Hans Verkuil and he tried them out at the time and basically pronounced them "ok" but I think even he wasn't sure if it was doing everything right.
That was a while ago and the cx25840 driver has undergone enough other changes to make merging those patches a lot more difficult - plus the v4l-subdevice stuff needs additional changes to support the extra cropping API.
-Mike
Signature · 3 lines
Mike Isely isely @ isely (dot) net PGP: 03 54 43 4D 75 E5 CC 92 71 16 01 E2 B5 F5 C1 E8
Quoted 31 lines · On Friday 26 June 2009 18:33:11 Mike Isely wrote:
Quoted 9 lines · jmdk
Hello,
I have a Hauppauge HVR-1900 which works fine with the pvrusb2 driver. However because most TV channels now air with 16:9 content inside 4:3 images, I would like to crop out the top and bottom black bars before encoding via the hardware MPEG2 encoder. I tried using the
ctl_crop_topandctl_crop_heightin /sysfs as well as the --set-crop option of v4l2-ctrl but only received error messages indicating a value out of range.Quoted 4 lines
The card has a cx25843 which should support cropping. Does anyone know how to get this feature to work ?
Thanks in advance for the help,
Unfortunately the cx25840 driver does not implement any cropping capability and the recent change to the v4l-subdevice architecture currently lacks the API entrypoints to make such a thing possible :-(
A pvrusb2 user a while back (it's in the pvrusb2 list archives) came up with some patches to the cx25840 driver that implement cropping. He also generated corresponding patches for the pvrusb2 driver. I merged his pvrusb2 patches (which is why you see that support in the driver) but not the cx25840 patches since I'm not an expert on that chip and I don't have the ability to verify that the patches preserve correct behavior for all the other devices that use the same chip. I did pass the cx25840 patches to Hans Verkuil and he tried them out at the time and basically pronounced them "ok" but I think even he wasn't sure if it was doing everything right.
Quoted 4 lines
That was a while ago and the cx25840 driver has undergone enough other changes to make merging those patches a lot more difficult - plus the v4l-subdevice stuff needs additional changes to support the extra cropping API.
Just a quick heads-up: the cropping API will be added to the v4l2_subdev API soon. A pull request from Guennadi that does this is already posted to the list.
Regards,
Hans
Signature · 1 line
Hans Verkuil - video4linux developer - sponsored by TANDBERG Telecom
Quoted 31 lines · Mike Isely
Quoted 9 lines · jmdk
Hello,
I have a Hauppauge HVR-1900 which works fine with the pvrusb2 driver. However because most TV channels now air with 16:9 content inside 4:3 images, I would like to crop out the top and bottom black bars before encoding via the hardware MPEG2 encoder. I tried using the
ctl_crop_topandctl_crop_heightin /sysfs as well as the --set-crop option of v4l2-ctrl but only received error messages indicating a value out of range.Quoted 4 lines
The card has a cx25843 which should support cropping. Does anyone know how to get this feature to work ?
Thanks in advance for the help,
Unfortunately the cx25840 driver does not implement any cropping capability and the recent change to the v4l-subdevice architecture currently lacks the API entrypoints to make such a thing possible :-(
A pvrusb2 user a while back (it's in the pvrusb2 list archives) came up with some patches to the cx25840 driver that implement cropping. He also generated corresponding patches for the pvrusb2 driver. I merged his pvrusb2 patches (which is why you see that support in the driver) but not the cx25840 patches since I'm not an expert on that chip and I don't have the ability to verify that the patches preserve correct behavior for all the other devices that use the same chip. I did pass the cx25840 patches to Hans Verkuil and he tried them out at the time and basically pronounced them "ok" but I think even he wasn't sure if it was doing everything right.
Quoted 4 lines
That was a while ago and the cx25840 driver has undergone enough other changes to make merging those patches a lot more difficult - plus the v4l-subdevice stuff needs additional changes to support the extra cropping API.
Not only that, doing cropping with the CX2584x chips and friends appears to break VBI extraction in interaction with the CX2341x encoding engine.
A good bit of experimentation would need to be done to keep VBI working with cropping.
Regards,
Andy
Quoted 1 line
-Mike