[FFmpeg-trac] #11127(avcodec:closed): FFV1 sometimes encodes invalid values for "ec" (CRC error detection/correction) header parameter field when using 2-pass encoding

[FFmpeg]

#11127: FFV1 sometimes encodes invalid values for "ec" (CRC error
detection/correction) header parameter field when using 2-pass encoding
-------------------------------------+-------------------------------------
             Reporter:  James        |                    Owner:  (none)
  Johnston                           |
                 Type:  defect       |                   Status:  closed
             Priority:  normal       |                Component:  avcodec
              Version:  unspecified  |               Resolution:
                                     |  worksforme
             Keywords:  FFV1 ffv1    |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
Changes (by Michael Niedermayer):

 * status:  new => closed
 * resolution:   => worksforme

Comment:

 The ec value is 1 in the file, you can see this by using:
 {{{
 ./ffmpeg -debug 1  -i ~/tickets/11127/Example\ file\ with\ invalid\ ec\
 header.mkv  2>&1 | grep 'ffv1 @'
 [ffv1 @ 0x559dd34bb180] global: ver:3.4, coder:2, colorspace: 0 bpr:8
 chroma:1(1:0), alpha:0 slices:2x2 qtabs:2 ec:1 intra:1 CRC:0x4333E8AE
 [ffv1 @ 0x559dd34bb180] ver:3 keyframe:1 coder:2 ec:1 slices:4 bps:8
 [ffv1 @ 0x559dd34bb180] slice 3, CRC: 0xEA3F94B1
 [ffv1 @ 0x559dd34bb180] slice 2, CRC: 0x262733FF
 [ffv1 @ 0x559dd34bb180] slice 1, CRC: 0xEBFDC675
 [ffv1 @ 0x559dd34bb180] slice 0, CRC: 0x62607DF5
 }}}

 So i cannot help, ffmpeg decodes it fine and ffmpeg sees a ec value of 1
 If some  other code sees a value that is not 1, its really that other code
 that needs to be looked into. There must be a difference between it and
 FFmpeg as the same input produces different values.
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/11127#comment:4>
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