On Mon, Apr 12, 2021 at 7:44 AM Daniel Playfair Cal < daniel.playfair....@gmail.com> wrote:
> > Ok, dfov for width != height in (d)fisheye have been fixed. > > Great, thanks :) > > > The aspect ratio one breaks handling in case input is in equirectangular > format. > > That's not obvious to me - can you provide an example filtergraph > where it breaks, and explain why it's wrong? > > > Dunno what to do with rest of patches. > > The most important one I think is the visibility test for fisheye > input - that is the only one that can't be worked around. > > Going back to your original example: > > `v360=input=e:output=fisheye:h_fov=180:v_fov=180,v360=input=fisheye:output=e:ih_fov=180:iv_fov=180` > > Now that you've added the ability to specify fov settings for the > equirectangular projection, you can apply my patch and still have the > output you expect, for example: > > > v360=input=e:output=fisheye:h_fov=180:v_fov=180,v360=input=fisheye:output=e:ih_fov=180:iv_fov=180:h_fov=180 > > The use of h_fov on the output prevents anything outside of 180 > horizontal field of view from being mapped (because its outside the > bounds of the output image). > That is not same output, The transparent part is completely missing. Perhaps another option should be added somehow. > > At the same time, its possible to map an entire fisheye image > including the corners, for example in my use case of converting > fisheye -> flat. > > On Sun, Apr 11, 2021 at 6:23 PM Paul B Mahol <one...@gmail.com> wrote: > > > > Ok, dfov for width != height in (d)fisheye have been fixed. > > > > Dunno what to do with rest of patches. > > > > The aspect ratio one breaks handling in case input is in equirectangular > format. > > > > On Sun, Apr 11, 2021 at 6:48 AM Daniel Playfair Cal < > daniel.playfair....@gmail.com> wrote: > >> > >> > AFAIK, the h/v/d fov works fine with fisheye in/out. I used synthetic > fisheye images from paul bourke site. > >> > >> > And diagonal fov from w/h either works with both in and out or not at > all. > >> > >> That doesn't seem correct. If an image with an equidistant projection > >> is of dimensions WxH and has the focal point at the center, then the > >> fields of view are related as follows for some value of f: > >> horizontal: f*W > >> vertical: f*H > >> diagonal: f*sqrt( W^2 + H^2 ) > >> > >> In the example I gave, v360 chooses horizontal/vertical fields of view > >> that are incompatible with the diagonal field of view provided. > >> Therefore (assuming 1:1 pixel aspect ratio), since > >> sqrt(116.66^2+87.5^2) = 145.83, `input=fisheye:id_fov=145.83` should > >> behave the same as `input=fisheye:ih_fov=116.66:iv_fov=87.50` in terms > >> of the focal length. It doesn't, so I think this is a bug. > >> > >> > So you want to not discard pixels out of circle defined by fov? That > generally does not make sense to me as that may not gonna have actual > pixels that belong to output. > >> > >> What circle/FoV are you referring to? The FoV depends on which points > >> on the image you choose to compare (for example the > >> horizontal/vertical/diagonal FoVs are all different). > >> Sometimes/usually there is no circle which describes which points in > >> the image can be correctly mapped. > >> > >> If a pixel in an image lies at a point where the projection of that > >> image is not defined, then yes it should be discarded. I think this is > >> correct in my patches. > >> > >> > Make sure that your files have correct projection, fisheye in v360 is > strict equidistant mapping, and may not be what your input is actually. > >> > >> Yes, I agree we shouldn't assume anything based on the > >> content/appearance of the images from my GoPro. But it's possible to > >> make a rectangular image of 1920x1440 pixels with an equidistant > >> fisheye projection where the horizontal, vertical, and diagonal FoV is > >> 116.66, 87.5, and 145.83. All the pixels in that image are defined in > >> the equidistant projection, so I think it should be possible for v360 > >> to map all the pixels to an appropriate output. If my image is not a > >> real equidistant fisheye projection, or if my FoV measurements are > >> wrong, then the chessboard won't have the right shape in the output. > >> This is not the problem I am trying to solve here. > >> > >> On Sun, Apr 11, 2021 at 9:37 AM Paul B Mahol <one...@gmail.com> wrote: > >> > > >> > > >> > > >> > On Mon, Mar 22, 2021 at 1:35 PM Daniel Playfair Cal < > daniel.playfair....@gmail.com> wrote: > >> >> > >> >> > I disagree, if I use 180 hfov and 180 vfov it should not have > extra areas but only half of previous input. > >> >> > >> >> Not sure I follow - the ih_fov and vh_fov refer to the input (i.e. > the fisheye image). If you wanted to restrict the FoV of the output, surely > the way to do that would be to implement and use the FoV settings for the > equirectangular projection?. It doesn't seem right that the code for the > input projection is responsible for deciding what appears in the output. My > understanding was that the FoV settings simply describe the focal length of > the input or output camera so that points in the images can me mapped > to/from 3d coordinates. > >> >> > >> >> To give you an idea of what I am trying to fix, here is an example > input: https://photos.app.goo.gl/o51NfY6aqWn3unPG6 > >> >> This is a 1920x1440 image taken on a GoPro Hero 5 black with the 4:3 > Wide FoV setting and stabilisation disabled. > >> >> > >> >> The following filtergraph demonstrates the issues: > 'v360=input=fisheye:ih_fov=116.66:iv_fov=87.50:output=flat:d_fov=145.8' > >> >> 1. the dfov_from_hfov issue is worked around by the use of ih_fov > and iv_fov instead of id_fov, although you can try with id_fov=145.8 to see > that problem too > >> > > >> > > >> > AFAIK, the h/v/d fov works fine with fisheye in/out. I used synthetic > fisheye images from paul bourke site. > >> > And diagonal fov from w/h either works with both in and out or not at > all. > >> > > >> >> > >> >> 2. by default the output has double the aspect ratio of the input, > even though the fisheye -> rectilinear transformation doesn't change the > aspect ratio (assuming the entire input image is included as it is in this > example) > >> >> 3. much of the input is not visible in the output even though there > is a mapping between the chosen projections (changed in the visibility test > patch) > >> >> > >> >> 3 in particular I don't think can be solved by changing the settings > - the input field of view needs to match the FoV of the input camera, > otherwise the mapping is wrong. But it seems there is no other way to > include the entire input from a fisheye image. > >> > > >> > > >> > So you want to not discard pixels out of circle defined by fov? That > generally does not make sense to me as that may not gonna have actual > pixels that belong to output. > >> > > >> > Make sure that your files have correct projection, fisheye in v360 is > strict equidistant mapping, and may not be what your input is actually. > >> > > >> > > >> >> > >> >> > >> >> On Mon, Mar 22, 2021 at 5:59 PM Paul B Mahol <one...@gmail.com> > wrote: > >> >>> > >> >>> > >> >>> > >> >>> On Mon, Mar 22, 2021 at 5:09 AM Daniel Playfair Cal < > daniel.playfair....@gmail.com> wrote: > >> >>>> > >> >>>> I've tried that filtergraph and a few other similar ones and I'm > not sure what you mean - what exactly is the regression? > >> >>>> > >> >>>> I tried it on this image with an equirectangular projection: > https://wiki.panotools.org/images/0/01/Big_ben_equirectangular.jpg > >> >>>> > >> >>>> The only difference I can see is that there are less unmapped > areas in the output with the patches, because the final mapping from the > output equirectangular image to the intermediate fisheye image no longer > fails to map some areas which are present in the fisheye image. I would > describe this as an improvement? > >> >>> > >> >>> > >> >>> I disagree, if I use 180 hfov and 180 vfov it should not have extra > areas but only half of previous input. > >> >>> > >> >>>> > >> >>>> > >> >>>> On Mon, Mar 22, 2021 at 3:30 AM Paul B Mahol <one...@gmail.com> > wrote: > >> >>>>> > >> >>>>> Sorry, but I cannot apply this set as is, It makes at least one > serious regression. > >> >>>>> > >> >>>>> For example try this filtergraph: > >> >>>>> > >> >>>>> > v360=input=e:output=fisheye:h_fov=180:v_fov=180,v360=input=fisheye:output=e:ih_fov=180:iv_fov=180 > >> >>>>> > >> >>>>> On Sun, Mar 21, 2021 at 1:45 PM Daniel Playfair Cal < > daniel.playfair....@gmail.com> wrote: > >> >>>>>> > >> >>>>>> This changes the iflat_range and flat_range values for the > fisheye > >> >>>>>> projection to match their meaning for the flat/rectilinear > projection. > >> >>>>>> That is, the range is between the two x or two y coordinates of > the > >> >>>>>> outermost points above/below or left/right of the center, in the > >> >>>>>> flat/rectilinear projection. > >> >>>>>> > >> >>>>>> Signed-off-by: Daniel Playfair Cal < > daniel.playfair....@gmail.com> > >> >>>>>> --- > >> >>>>>> libavfilter/vf_v360.c | 19 +++++++++---------- > >> >>>>>> 1 file changed, 9 insertions(+), 10 deletions(-) > >> >>>>>> > >> >>>>>> diff --git a/libavfilter/vf_v360.c b/libavfilter/vf_v360.c > >> >>>>>> index 68bb2f7b0f..3158451963 100644 > >> >>>>>> --- a/libavfilter/vf_v360.c > >> >>>>>> +++ b/libavfilter/vf_v360.c > >> >>>>>> @@ -2807,9 +2807,8 @@ static int > prepare_fisheye_out(AVFilterContext *ctx) > >> >>>>>> { > >> >>>>>> V360Context *s = ctx->priv; > >> >>>>>> > >> >>>>>> - s->flat_range[0] = s->h_fov / 180.f; > >> >>>>>> - s->flat_range[1] = s->v_fov / 180.f; > >> >>>>>> - > >> >>>>>> + s->flat_range[0] = 0.5f * s->h_fov * M_PI / 180.f; > >> >>>>>> + s->flat_range[1] = 0.5f * s->v_fov * M_PI / 180.f; > >> >>>>>> return 0; > >> >>>>>> } > >> >>>>>> > >> >>>>>> @@ -2827,8 +2826,8 @@ static int fisheye_to_xyz(const > V360Context *s, > >> >>>>>> int i, int j, int width, int height, > >> >>>>>> float *vec) > >> >>>>>> { > >> >>>>>> - const float uf = s->flat_range[0] * ((2.f * i) / width - > 1.f); > >> >>>>>> - const float vf = s->flat_range[1] * ((2.f * j + 1.f) / > height - 1.f); > >> >>>>>> + const float uf = 2.f * s->flat_range[0] / M_PI * ((2.f * i) > / width - 1.f); > >> >>>>>> + const float vf = 2.f * s->flat_range[1] / M_PI * ((2.f * j > + 1.f) / height - 1.f); > >> >>>>>> > >> >>>>>> const float phi = atan2f(vf, uf); > >> >>>>>> const float theta = M_PI_2 * (1.f - hypotf(uf, vf)); > >> >>>>>> @@ -2858,8 +2857,8 @@ static int > prepare_fisheye_in(AVFilterContext *ctx) > >> >>>>>> { > >> >>>>>> V360Context *s = ctx->priv; > >> >>>>>> > >> >>>>>> - s->iflat_range[0] = s->ih_fov / 180.f; > >> >>>>>> - s->iflat_range[1] = s->iv_fov / 180.f; > >> >>>>>> + s->iflat_range[0] = 0.5f * s->ih_fov * M_PI / 180.f; > >> >>>>>> + s->iflat_range[1] = 0.5f * s->iv_fov * M_PI / 180.f; > >> >>>>>> > >> >>>>>> return 0; > >> >>>>>> } > >> >>>>>> @@ -2882,10 +2881,10 @@ static int xyz_to_fisheye(const > V360Context *s, > >> >>>>>> { > >> >>>>>> const float h = hypotf(vec[0], vec[1]); > >> >>>>>> const float lh = h > 0.f ? h : 1.f; > >> >>>>>> - const float phi = atan2f(h, vec[2]) / M_PI; > >> >>>>>> + const float phi = atan2f(h, vec[2]); > >> >>>>>> > >> >>>>>> - float uf = vec[0] / lh * phi / s->iflat_range[0]; > >> >>>>>> - float vf = vec[1] / lh * phi / s->iflat_range[1]; > >> >>>>>> + float uf = 0.5f * vec[0] / lh * phi / s->iflat_range[0]; > >> >>>>>> + float vf = 0.5f * vec[1] / lh * phi / s->iflat_range[1]; > >> >>>>>> > >> >>>>>> const int visible = -0.5f < uf && uf < 0.5f && -0.5f < vf > && vf < 0.5f; > >> >>>>>> int ui, vi; > >> >>>>>> -- > >> >>>>>> 2.31.0 > >> >>>>>> > >> >>>>>> _______________________________________________ > >> >>>>>> ffmpeg-devel mailing list > >> >>>>>> ffmpeg-devel@ffmpeg.org > >> >>>>>> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > >> >>>>>> > >> >>>>>> To unsubscribe, visit link above, or email > >> >>>>>> ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe". > _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
