From: Philipp Zabel <p.zabel@pengutronix.de>
To: Steve Longerbeam <slongerbeam@gmail.com>, linux-media@vger.kernel.org
Cc: kernel@pengutronix.de, Nicolas Dufresne <nicolas@ndufresne.ca>
Subject: Re: [PATCH v2 00/16] i.MX media mem2mem scaler
Date: Mon, 23 Jul 2018 11:42:27 +0200 [thread overview]
Message-ID: <1532338947.3501.6.camel@pengutronix.de> (raw)
In-Reply-To: <1532338170.3501.4.camel@pengutronix.de>
On Mon, 2018-07-23 at 11:29 +0200, Philipp Zabel wrote:
[...]
> > Also, I'm trying to parse the functions find_best_seam() and
> > find_seams(). Can
> > you provide some more background on the behavior of those functions?
>
> The hardware limits us to restart linear sampling at zero with each
> tile, so find_seams() tries to find the (horizontal and vertical) output
> positions where the corresponding input sampling positions are closest
> to integer values.
> The distance between the ideal fractional input sampling position and
> the actual integer sampling position that can be achieved is the amount
> of distortion we have to introduce (by slightly stretching one input
> tile and slightly shrinking the other) to completely hide the visible
> seams.
Actually, this is not all of it. In addition to being an integer, the
input sampling position at seam start is still subject to alignment
restrictions, so the actual value that is minimized is the difference
between the ideal fractional input sampling position and the closest
aligned input position.
regards
Philipp
next prev parent reply other threads:[~2018-07-23 10:42 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-19 15:30 [PATCH v2 00/16] i.MX media mem2mem scaler Philipp Zabel
2018-07-19 15:30 ` [PATCH v2 01/16] gpu: ipu-v3: ipu-ic: allow to manually set resize coefficients Philipp Zabel
2018-07-19 15:30 ` [PATCH v2 02/16] gpu: ipu-v3: image-convert: prepare for per-tile configuration Philipp Zabel
2018-07-19 15:30 ` [PATCH v2 03/16] gpu: ipu-v3: image-convert: calculate per-tile resize coefficients Philipp Zabel
2018-07-19 15:30 ` [PATCH v2 04/16] gpu: ipu-v3: image-convert: reconfigure IC per tile Philipp Zabel
2018-07-19 15:30 ` [PATCH v2 05/16] gpu: ipu-v3: image-convert: store tile top/left position Philipp Zabel
2018-07-19 15:30 ` [PATCH v2 06/16] gpu: ipu-v3: image-convert: calculate tile dimensions and offsets outside fill_image Philipp Zabel
2018-07-19 15:30 ` [PATCH v2 07/16] gpu: ipu-v3: image-convert: move tile alignment helpers Philipp Zabel
2018-07-19 15:30 ` [PATCH v2 08/16] gpu: ipu-v3: image-convert: select optimal seam positions Philipp Zabel
2018-07-19 15:30 ` [PATCH v2 09/16] gpu: ipu-v3: image-convert: fix debug output for varying tile sizes Philipp Zabel
2018-07-19 15:30 ` [PATCH v2 10/16] gpu: ipu-v3: image-convert: relax tile width alignment for NV12 and NV16 Philipp Zabel
2018-07-19 15:30 ` [PATCH v2 11/16] gpu: ipu-v3: image-convert: relax input alignment restrictions Philipp Zabel
2018-07-19 15:30 ` [PATCH v2 12/16] gpu: ipu-v3: image-convert: relax output " Philipp Zabel
2018-07-19 15:30 ` [PATCH v2 13/16] gpu: ipu-v3: image-convert: fix bytesperline adjustment Philipp Zabel
2018-07-19 15:30 ` [PATCH v2 14/16] gpu: ipu-v3: image-convert: add some ASCII art to the exposition Philipp Zabel
2018-07-19 15:30 ` [PATCH v2 15/16] gpu: ipu-v3: image-convert: disable double buffering if necessary Philipp Zabel
2018-07-19 15:30 ` [PATCH v2 16/16] media: imx: add mem2mem device Philipp Zabel
2018-07-22 18:30 ` [PATCH v2 00/16] i.MX media mem2mem scaler Steve Longerbeam
2018-07-22 19:11 ` Steve Longerbeam
2018-07-23 9:29 ` Philipp Zabel
2018-07-23 9:42 ` Philipp Zabel [this message]
2018-07-23 13:26 ` Philipp Zabel
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