[FFmpeg-trac] #10990(undetermined:new): "Assertion best_input >= 0 failed" IFF upsampling AND complex filtergraph

[FFmpeg]

#10990: "Assertion best_input >= 0 failed" IFF upsampling AND complex filtergraph
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             Reporter:  Hunter       |                    Owner:  (none)
  Hogan                              |
                 Type:  defect       |                   Status:  new
             Priority:  normal       |                Component:
                                     |  undetermined
              Version:  git-master   |               Resolution:
             Keywords:  resampling   |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
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Comment (by paulgreyson):

 I ran into this problem processing a video filtergraph. I worked around it
 by explicitly setting vframes to just short (I used 30 frames but maybe
 fewer would work also) of the end of the input video. this filter graph is
 processing side-by-side stereoscopic video into an anaglyph.

 {{{
 "-filter_complex",
                 (
                     f"[0:v]crop=iw/2:ih:0:0,
 crop=iw-{input['crop']}:ih:{input['crop']}:0, scale=2*iw:ih, pad=iw:ih
 :(ow-iw)/2:0:black[left_base];"
                     f"[0:v]crop=iw/2:ih:iw/2:0,
 crop=iw-{input['crop']}:ih:0:0, scale=2*iw:ih, pad=iw:ih:(ow-
 iw)/2:0:black[right_base];"

 f"[left_base]pad=iw+{input['left_adjust']}:ih+{(16.0/9)*input['left_adjust']}:{input['left_adjust']/2}:{(16.0/9)*input['left_adjust']/2}:black[left_adjusted];"

                     f"[right_base][left_adjusted]scale2ref[right][left];"

 f"[left]eq=brightness=0.1:contrast=1.2:gamma=1.1[left_filtered];"
 f"[right]eq=brightness={brightness}:contrast={contrast}:gamma={gamma}[right_filtered];"


                     f"[left_filtered]lutrgb=r=val*{lut}[left_lut];"
 f"[right_filtered]lutrgb=g=val*{lut}:b=val*{lut}[right_lut];"

 f"[left_lut]drawtext=fontfile={font}:text='{input['title']}':fontcolor=white:fontsize=48:box=1:boxcolor=black at 0.5:boxborderw=5:x={title_depth_offset}+(w-text_w)/2:y=(h-text_h*2):enable='{enable}'[left_final];"
 f"[right_lut]drawtext=fontfile={font}:text='{input['title']}':fontcolor=white:fontsize=48:box=1:boxcolor=black at 0.5:boxborderw=5:x=-{title_depth_offset}+(w-text_w)/2:y=(h-text_h*2):enable='{enable}'[right_final];"

                     f"[left_final][right_final]hstack,
 stereo3d=sbsl:{stereo3d_mode}, pad=1920:ih:(ow-iw)/2:ih:black,
 crop=1920:1080:0:1080-ih"
 )
 }}}
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/10990#comment:2>
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