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Old 14th March 2019, 03:38   #21  |  Link
filler56789
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Quote:
Originally Posted by manolito View Post
Please I need some clarifications here...

Does this only apply to the X264 input, or does this mean that older player software or hardware won't be able to decode files created with this version any longer?
Applies to the 4:4:4 [i.e., without chroma subsampling] streams generated by the newer x264 binaries:

Code:
-    if( i_csp >= X264_CSP_I444 && h->param.b_cabac )
-    {
-        /* Disable 8x8dct during 4:4:4+CABAC encoding for compatibility with libavcodec */
-        h->param.analyse.b_transform_8x8 = 0;

Last edited by filler56789; 14th March 2019 at 03:38. Reason: disambiguation
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Old 14th March 2019, 04:06   #22  |  Link
manolito
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Thanks, I don't care about 4:4:4 chroma so I won't be affected...
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Old 14th March 2019, 06:48   #23  |  Link
LigH
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I assume that libav fixed the decoding of strict video streams already a while ago, so x264 can now safely remove the compatibility changes for libav before a threshold date. But I don't know which date.
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Old 14th March 2019, 06:52   #24  |  Link
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Quote:
Originally Posted by LigH View Post
Quote:
Remove compatibility workarounds
This will break decoding with older versions of FFmpeg/Libav.
So keep your decoders up to date. I don't know how old is "too old" here...
Too old versions would mean versions before June/July of 2017. Corresponding patches where:
FFmpeg
avcodec/h264_cabac: Fix CABAC+8x8dct in 4:4:4
avcodec/h264_mb: Fix 8x8dct in lossless for new versions of x264
Libav
h264_cabac: Fix CABAC+8x8dct in 4:4:4
h264dec: fix Lossless Decoding (Profile 244) for 8x8 Intra Prediction

With old versions of FFmpeg/Libav you can have problems decoding lossless or 4:4:4+CABAC streams encoded with new x264.
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Old 14th March 2019, 10:02   #25  |  Link
LigH
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Okay ...
Quote:
Originally Posted by MasterNobody View Post
versions before June/July of 2017
means that ffmpeg v3.4 (released shortly after) should have it fixed already, and v4.x quite certainly.
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Old 14th March 2019, 10:14   #26  |  Link
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You can remain compatible to "old" and "new" lossless ffmpeg decoding by setting --no-8x8dct at <1% compression loss.

But: is "Remove compatibility workarounds" really in your builds? It's still only part of the "master", not the "stable" branch. Has been like that since almost 2 years now.
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Old 14th March 2019, 10:35   #27  |  Link
nevcairiel
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Originally Posted by sneaker_ger View Post
But: is "Remove compatibility workarounds" really in your builds? It's still only part of the "master", not the "stable" branch. Has been like that since almost 2 years now.
Actually "Remove compatibility workarounds" was only in the experimental sandbox for 2 years, it moved to master 7 days ago, and will presumably be in the next stable push, unless they take it back out at some point, since stable is generally "just" an older master.
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Old 14th March 2019, 10:35   #28  |  Link
LigH
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MABS update logs for x264-git report:

Code:
HEAD is now at d4099dd4 Remove compatibility workarounds
And it jumped from x264 0.157.2945 72db437 to x264 0.157.2969 d4099dd within few hours yesterday. So maybe there was a merge?
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Old 14th March 2019, 10:44   #29  |  Link
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Quote:
Originally Posted by nevcairiel View Post
Actually "Remove compatibility workarounds" was only in the experimental sandbox for 2 years, it moved to master 7 days ago, and will presumably be in the next stable push, unless they take it back out at some point, since stable is generally "just" an older master.
I see.

Can confirm the changes are also already in the "official" binaries from videolan.
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