[FFmpeg-trac] #9958(undetermined:new): thd encoder bug: Plex and LG C9 have same artefacts

[FFmpeg]

#9958: thd encoder bug: Plex and LG C9 have same artefacts
-------------------------------------+-------------------------------------
             Reporter:  Balling      |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:  git-
  undetermined                       |  master
             Keywords:  thd          |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 Summary of the bug: '''first of all there is no bug with our ffmpeg
 decoder, it is all 24 bits lossless and gapless.''' But that is an
 illusion: for a very long time Plex Transcoder.exe with eae.exe decoder
 could not decode produced by ffmpeg thd. Now it can thanks to Paul's
 fixes, so it is now obvious it is has same artefacts '''SAME AS''' in LG
 C9 HW decoder, bitstreamed by Lavfilters. I would imagine drp.exe (Dolby
 reference player) will also have those. Official encoder does not have
 such artefacts (DEE or Dolby media encoder).

 How to reproduce: buy LG C9 or use instruction to get EAE.exe decoder.
 https://forum.doom9.org/showpost.php?p=1974530&postcount=185

 Then decode this sample, encoded with git-master ffmpeg (48k has the same
 artefacts): https://0x0.st/oJBN.thd

 and compare how ffmpeg decodes it with how Plex and LG C9 does, here is it
 (16 bit has the same artefacts, artefacts start at 00:01:02):
 https://0x0.st/oJBb.wav

 Dolby Media Encoder at least appears to be without artefacts, alas it
 cannot encode 44.1, so I did on 16 bits ffmpeg.exe -i "sample.thd" -ar
 48000 48.wav (https://0x0.st/oJBA.wav) and encoded with Dolby Media
 Encoder:  https://0x0.st/oJBa.mlp

 I will just mention how much bigger the ffmpeg file is, compared to
 oJBa.mlp. https://0x0.st/oJBM.thd
 Patches should be submitted to the ffmpeg-devel mailing list and not this
 bug tracker.
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/9958>
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