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Hans de Goede wrote: > On 04/04/2009 10:22 PM, Erik Andrén wrote: >> -----BEGIN PGP SIGNED MESSAGE----- >> Hash: SHA1 >> >> Hi, >> >> While trying to get hflip and vflip working for the stv06xx webcam >> bridge coupled to the vv6410 sensor I've come across the following >> problem. >> >> When flipping the image horizontally, vertically or both, the sensor >> pixel ordering changes. In the m5602 driver I was able to compensate >> for this in the bridge code. In the stv06xx I don't have this >> option. One way of solving this problem is by changing the >> pixelformat on the fly, i. e V4L2_PIX_FMT_SGRB8 is the normal >> format. When a vertical flip is required, change the format to >> V4L2_SBGGR8. >> >> My current understanding of libv4l is that it probes the pixelformat >> upon device open. In order for this to work we would need either >> poll the current pixelformat regularly or implement some kind of >> notification mechanism upon a flipping request. >> >> What do you think is this the right way to go or is there another >> alternative. >> > > The changing of the pixelformat only happens when you flip the data > before conversion. If you look at the current upside down handling > code you will see it does the rotate 180 degrees after conversion. > > This is how the vflip / hflip should be handled too. We only have > 4 (2 really since we don't care about r versus b / u versus v while > flippiing) destination formats for which we then need to write flipping > code. Otherwise we need to write flipping code for *all* supported input > formats, not to mention flipping some input formats is close to impossible > (JPEG for example). > So you mean we should do the vflip/hflip in software, just exposing one native format? Best regards, Erik > Regards, > > Hans > > p.s. > > One problem with this approach is that if an apps ask for a native > cam format which is not one which we can also convert to, the > flipping won't work. I think this is best solved by simply not > listing the native formats in the enum-fmt output when the cam > needs flipping. > > -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (GNU/Linux) iEYEARECAAYFAknYlVoACgkQN7qBt+4UG0FwqACfQtawSmcm8rtFUCGZtV9pzVd+ jmkAoKHkibnapkZkDfl4pXd8pjaJ9M0E =odkv -----END PGP SIGNATURE----- -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
