[FFmpeg-user] Documentation for Ffmpeg remap filter

[Paul B Mahol]

On 8/6/17, Evert Vorster <evorster at gmail.com> wrote:
> Hi there.
>
> I have been able to use ffmpeg to convert dual fisheye samsung gear 360
> footage to equirectangular footage with ffmpeg.
>
> The example program given in the manual does an OK job of what the remap
> filter is capable of, however to really get the best from it the .pgm maps
> needs to be created with something that takes lens chataristics into
> account.
>
> Passing the -c parameter to Panotool's nona generates the required
> translation maps in .tif format, and then it's a doddle to convert to .pgm
> with ImageMagick.

FFmpeg can read tif format just fine last time I checked.

>
> Is there a way to update the manual a little for other people who wants to
> folow in my footsteps?
>
> For the curious, here is the contents of the script that I use.
> --------------------------------------------------------------------------------------
> #!/bin/bash
> #This will split, defish, blend and re-assemble Samsung Gear 360 video
> map_dir="/data/Projects/RemapFilter"
> ffmpeg -y -i "$1" \
> -i $map_dir/lx.pgm -i $map_dir/ly.pgm -loop 1 \
> -i $map_dir/Alpha-Map.png \
> -i $map_dir/rx.pgm -i $map_dir/ry.pgm \
> -c:v hevc_nvenc -rc constqp -qp 26 -cq 26 \
> -filter_complex \
> "[0:v]eq=contrast=0.8:brightness=-0.01:gamma=0.7:saturation=0.8[bright]; \
>  [bright]split=2[in1][in2]; \
>  [in1]crop=in_w/2:in_h:0:in_h[l_crop];\
>  [in2]crop=in_w/2:in_h:in_w/2:in_h[r_crop]; \
>  [3]alphaextract[alf]; \
>  [l_crop]vignette=angle=PI/4.6:mode=backward[l_vignette]; \
>  [l_vignette][1][2]remap[l_remap]; \
>  [r_crop]vignette=angle=PI/4.8:mode=backward[r_vignette]; \
>  [r_vignette][4][5]remap[r_remap]; \
>  [l_remap]crop=in_w:1920:0:(in_h-1920)/2[l_rm_crop]; \
>  [r_remap]crop=in_w:1920:0:(in_h-1920)/2[r_rm_crop]; \
>  [l_rm_crop][alf]alphamerge[l_rm_crop_a]; \
>  [l_rm_crop_a]split=2[l_rm_crop1][l_rm_crop2]; \
>  [l_rm_crop1]crop=in_w/2:in_h:0:0[l_rm_crop_l]; \
>  [l_rm_crop2]crop=in_w/2:in_h:in_w/2:0[l_rm_crop_r]; \
>  [0:v][r_rm_crop]overlay=(1920-(2028/2)):0[ov1]; \
>  [ov1][l_rm_crop_l]overlay=((1920+2028/2)-(2028-1920)):0[ov2]; \
>  [ov2][l_rm_crop_r]overlay=0:0[out]" \
> -map [out] -map 0:a "$1_Remapped.mp4"
> --------------------------------------------------------------------------------------------
> I hope this helps somebody.
>
> Kind regards
> --
> Evert Vorster
> Isometrix Acquistion Superchief
> _______________________________________________
> ffmpeg-user mailing list
> ffmpeg-user at ffmpeg.org
> http://ffmpeg.org/mailman/listinfo/ffmpeg-user
>
> To unsubscribe, visit link above, or email
> ffmpeg-user-request at ffmpeg.org with subject "unsubscribe".