[FFmpeg-trac] #1726(undetermined:closed): Mono TrueHD file fails to decode
FFmpeg
trac at avcodec.org
Fri Sep 3 02:47:11 EEST 2021
#1726: Mono TrueHD file fails to decode
-------------------------------------+-------------------------------------
Reporter: Carl Eugen | Owner: (none)
Hoyos |
Type: defect | Status: closed
Priority: important | Component:
| undetermined
Version: git-master | Resolution: fixed
Keywords: thd | Blocked By:
regression mlp |
Blocking: | Reproduced by developer: 1
Analyzed by developer: 0 |
-------------------------------------+-------------------------------------
Comment (by Balling):
Interesting, so even now with 16 samples present, the reencoded file is
larger (13866334 bytes vs 11141326 bytes) but also no longer has flags to
drop the second channel and does not print with -v debug "Mono stream with
2 substreams, ignoring 2nd".
P.S. It is not printing stereo, but it creates wrong wav with 2 channels
with second channel zeroed out in both source and reencoded file (when
ffmpeg recognized the file as mono, the result was the same, two channel
in wav).
P.S.2 WHAT IS VERY IMPORTANT is that LG C9 which uses hardware decoder for
Truehd and Truehd + Atmos (yep, it decodes Atmos packed in MAT 2.0 by
Lavfilters even on the internal speackers and signals Atmos) thinks that
the reencoded truehd file is not longer mono: when you select Right+Right
in the LG C9 sound menu it plays nothing on reencoded file (because
reencoded file has nothing in the right channel and is not tagged as mono)
while on source file Right+Right is the same as L+R and L+L, since mono is
being played on all speakers. What is also a problem is that reencoded
file is so much less loud and also that it loses sound when you select
only one speacker (R+R is no sound as I said but left+left is less loud
again). That may be a difference between stereo and mono or DRC (Dynamic
range compression) that is not supported in mlpenc (while eac3 and ac3 do
support it).
--
Ticket URL: <https://trac.ffmpeg.org/ticket/1726#comment:5>
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