#9958: thd encoder bug: Plex and LG C9 have same artefacts
------------------------------------+------------------------------------
Reporter: Balling | Owner: (none)
Type: defect | Status: reopened
Priority: minor | Component: avcodec
Version: git-master | Resolution:
Keywords: thd | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
------------------------------------+------------------------------------
Description changed by Balling:
Old description:
> 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.
New description:
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
EasyAudioEncoder.exe decoder could not decode produced by ffmpeg thd. Now
it can thanks to Paul's fixes, so it is now obvious it 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
Mono does not have such artefacts.
Patches should be submitted to the ffmpeg-devel mailing list and not this
bug tracker.
--
--
Ticket URL: <https://trac.ffmpeg.org/ticket/9958#comment:8>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker
_______________________________________________
FFmpeg-trac mailing list
FFmpeg-trac@avcodec.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-trac
To unsubscribe, visit link above, or email
ffmpeg-trac-requ...@ffmpeg.org with subject "unsubscribe".
