x262 Development Thread

[Emulgator]

ffmpeg decoded to .y4m.
y4m input to x262 r2433_debug: The same behaviour.

Any --preset <faster than slower> succeeds.
Any --preset <slower than slow> fails.

y4m frontend reports 720x576i 16:15 @ 25/1 fps <cfr>
x262: no warnings.

What kicks in at --preset slower ?
--partitions all broken ? --trellis 2 broken ? --rc-lookahead 60 ? --ref 8 ? --subme 9 ?

[Emulgator]

Now commenting all the <slower> parameters in one by one.

Ah, found it: --subme 9 breaks it. --subme 10 and --subme 11 fail as well.

P.S. Could repeat the bug on a Win7U64 system, CPU i7 920XM.
Here in Win7 the cmd window stays open, but: Silent abort, no message

[ifb]

Now commenting all the <slower> parameters in one by one.

Ah, found it: --subme 9 breaks it. --subme 10 and --subme 11 fail as well.

P.S. Could repeat the bug on a Win7U64 system, CPU i7 920XM.
Here in Win7 the cmd window stays open, but: Silent abort, no message
I can reproduce a segfault using your original commandline with --threads 1, but the backtrace is pretty useless. I'll have to look at this later.

<edit>
OK. I see what's happening. I'll work on it tonight.
</edit>

[ifb]

Fixed (https://github.com/kierank/x262/commit/6fe55fd27ed39682a707d45f75749d4fb06c4f29). Both veryslow and placebo were tested, but somehow the usual test clips never triggered this (or at least didn't crash in it).

New build:
x262 0.128.0+2443 6fe55fd (http://www.mediafire.com/download.php?f5s9yrjltu1xln5)

There's still a known bug in interlaced chroma, but at least this crash is fixed.

[Emulgator]

Many thanks, this commit fixes the subme>8 bug on my side as well.

[Emulgator]

Now the residual block structures, especially visible at scenecuts (shown are pairs of consecutive frames):

Cut to Black.
Frame 413:
http://dvd-manufactur.de/files/x262r2443_Frame_000413.jpg

Frame 414:
http://dvd-manufactur.de/files/x262r2443_Frame_000414.jpg

Cut from Black.
Frame 417:
http://dvd-manufactur.de/files/x262r2443_Frame_000417.jpg

Frame 418:
http://dvd-manufactur.de/files/x262r2443_Frame_000418.jpg

Another Cut to Black.
Frame 542:
http://dvd-manufactur.de/files/x262r2443_Frame_000542.jpg

Frame 543:
http://dvd-manufactur.de/files/x262r2443_Frame_000543.jpg

The x262_r2443 encode: (http://dvd-manufactur.de/files/PAL-DVD2_r2443.m2v) (x262 r2421, r2433 through r2443 do exhibit the same)

[zmejce]

I'm using this commands on x264:

--crf 20 --tune film --b-adapt 2 --direct auto --demuxer raw --input-csp i420 --input-res %(width)x%(height) --fps %(fpsnum)/%(fpsden) -o "%(tempvideofile)" -

Which commands would be the x262's equivalent?

Would x262 produce same quality as x264 for dvd riping and 1080 hd?

[zmejce]

I'm using this commands on x264:

--crf 20 --tune film --b-adapt 2 --direct auto --demuxer raw --input-csp i420 --input-res %(width)x%(height) --fps %(fpsnum)/%(fpsden) -o "%(tempvideofile)" -

Which commands would be the x262's equivalent?

Would x262 produce same quality as x264 for dvd riping and 1080 hd?

I've tried it with the latest x262 build and the same commands dont produce same quality-x262 is worse, but makes double smaller size. Ive tried also with crf 15 and the result was same filesize as crf 20 and same or very similar quality.

Tried it on 720x576 resolution video.

[ifb]

I'm using this commands on x264:

--crf 20 --tune film --b-adapt 2 --direct auto --demuxer raw --input-csp i420 --input-res %(width)x%(height) --fps %(fpsnum)/%(fpsden) -o "%(tempvideofile)" -

Which commands would be the x262's equivalent?

Would x262 produce same quality as x264 for dvd riping and 1080 hd?
--direct auto doesn't apply to MPEG-2.

Also, note that MPEG-2 is two generations older than H.264. For most content, there's no way x262 could ever match x264 quality at the same bitrate.

I've tried it with the latest x262 build and the same commands dont produce same quality-x262 is worse, but makes double smaller size. Ive tried also with crf 15 and the result was same filesize as crf 20 and same or very similar quality.

Tried it on 720x576 resolution video.
Again, MPEG-2 is old. Also, the CRF scale is quite different between x262/x264 (likely a bug - ratecontrol patches welcome). x262 will need a much lower CRF value.

[qyot27]

@zmejce:
Refer to this post (http://forum.doom9.org/showpost.php?p=1282676&postcount=2), although the problem in that thread was precisely the opposite of what's being discussed here (experiencing file bloat with x264 output because they used the quant values they were used to from DivX rather than bad quality in x262 because you were using typical crf values from x264).

Point being, MPEG-2 and MPEG-4 ASP both used linear scales, not a logarithmic one like H.264. Of course, this is assuming x262 is expecting values from a linear scale and not trying to adapt a log scale to MPEG-2. It's been too long since I tested with x262 to remember if that's the case.

[ifb]

@zmejce:
Refer to this post (http://forum.doom9.org/showpost.php?p=1282676&postcount=2), although the problem in that thread was precisely the opposite of what's being discussed here (experiencing file bloat with x264 output because they used the quant values they were used to from DivX rather than bad quality in x262 because you were using typical crf values from x264).

Point being, MPEG-2 and MPEG-4 ASP both used linear scales, not a logarithmic one like H.264. Of course, this is assuming x262 is expecting values from a linear scale and not trying to adapt a log scale to MPEG-2. It's been too long since I tested with x262 to remember if that's the case.MPEG-2 has linear and non-linear quant. x262 can do either, but non-linear (the default) is better.

[Biggiesized]

Where can we download the latest compiled binary?

[djonline]

High level is buggy, bad broken picture.

[djonline]

Also, I want to make 720p/60p with 60fps. How can I do this with x262 ?

[Adub]

Write an Avisynth script to convert/feed your video in a 720p/60fps format and then pipe it into x262.

[ifb]

High level is buggy, bad broken picture.

And may remain so without steps to reproduce. Please post your full commandline.

[Boulder]

Is the encoder "safe to use" in everyday things? I occasionally need to author some DVDs and there's always nice to have extra items in the toolbox.

[kieranrk]

Please test with latest patch.

[Emulgator]

A build, a build, a kingdom for a build...

[LoRd_MuldeR]

http://www.mediafire.com/file/ec81p13yvb48esz/x262.2013-04-08.rar

[ifb]

A build, a build, a kingdom for a build...
fprofiled with lavf and ffms2:
x262 32-bit (http://www.mediafire.com/download.php?cx2d6dzjmsro6tp)
x262 64-bit (http://www.mediafire.com/download.php?amk2cgp85k84r6c)

[kieranrk]

There's a crash in interlaced mode (b16x8)

[Emulgator]

Many thanks, Mulder and ifb !
Soon crunching...

[Emulgator]

Yes, I can confirm the crash of ifb's x262 r2508 (32bit) after a few frames for a interlaced PAL-SD-Source
when called as x262 to encode H.262. If renamed and called as x264 r2508 delivers a proper H.264 encode.

For x262:
MediaInfo reports a duration of 160ms (4 PAL frames), MediaPlayerClassic with ffdshow can play 2 frames.

Output was specified as .m2v.
Once I additionally give the argument -mpeg2 as listed in -fullhelp, x262 crashes immediately without encoding anything.

From -fullhelp
MPEG-2 (H.262):

-mpeg2 Encode as MPEG-2 instead of H.264
-dc <integer> Specify intra DC precision to use (8 to 11) [8]
-altscan Use alternate MPEG-2 VLC scan order, not zigzag
-linear-quant Use MPEG-2 linear quantization table
-no-altintra Use MPEG-1 VLCs (Table B.14) for intra blocks

Outfile type is selected by filename:
.264 -> Raw bytestream
.mkv -> Matroska
.flv -> Flash Video
.mp4 -> MP4 if compiled with GPAC support (yes)
Output bit depth: 8 (configured at compile time)

Shouldn't the extension .m2v should be listed in fullhelp as one of the triggers for MPEG-2 (H.262) encoding ?...

.m2v -> MPEG-2 (H.262)

Edit: Nah. I was wrong.
The output extension .m2v does not trigger H.262.

It is indeed:

{Or is it the call as x262.exe alone ?}

Renaming the suspicious x262.exe to x264.exe and running it with the same commandline
containing the output extension .m2v delivers a successful Level 3.1 H.264 encode,
with the (specified from me) misleading extension .m2v.

[develX]

There's a crash in interlaced mode (b16x8)


Yes, it only happens in interlaced mode and multithreaded configurations. It seams that the stack is overwritten (i_width > 16!!). When i rewrite this to input == output (build 129) then it crashs in refine_subpel()/x264_pixel_satd_8x8_sse4 (), line 913 (build 133).
Is there a newer version without that problems?

[kieranrk]

It's a known bug but I haven't had time to fix it: https://github.com/kierank/x262/issues/2

[develX]

It's a known bug but I haven't had time to fix it: https://github.com/kierank/x262/issues/2

Ok, I'll try it.

[kieranrk]

You can come on #x264dev on freenode if you need help.

[kieranrk]

Can anyone reproduce the interlaced crashes with the latest git? As far as I know they are gone.

[Emulgator]

A build would be nice.

[kieranrk]

A build would be nice.

I am not permitted to do that for various reasons.

[zerowalker]

https://www.sendspace.com/file/fng0dj

Here is my build of it.

Is x262 DVD Compliant?

EDIT:

Link Fixed*

[Emulgator]

Many thanks zerowalker, but this link seems wrong somehow...
PM ?

[Emulgator]

Many thanks ! Crash on interlaced footage is gone for me with zerowalker's build (x262 core140 r2615),
tested on the same clip as in 2013.
Residual block artifacts 1 frame after cuts to black still there.

[zerowalker]

I did check the quality of the encoder.
I didn't do any thorough testing, but the from the looks of it the quality is Good, but not more than that.
It seems to have a hard time on Edges, probably retaining details.

Disturbing thing is that x262 is called x264 in the command tool (IIRC?), other than that, well it's x264 with MPEG-2;)

[Procrastinating]

Nowadays, how does the encoded quality of x262 compare with CCE? Ie, under the best-possible quality settings(not necessarily DVD-compliant), on say 720p test footage. That is to say, ignoring bugs and under ideal conditions, which is "best"?

[Emulgator]

CCE, in particular SP3 is not yet beaten by x262 for DVD encoding.
But if the fixes for residual artifacts go on, x262 may well sit on top one day.
I see potential for good use of bitrate and very good detail retention.

[Blue_MiSfit]

I wonder how it compares to Elemental. I was impressed by their encoder's balance of detail preservation and lack of blocking at low bitrates (i.e. 14 Mbps 1080i29.97 for CableLabs VOD files) enough to pick it over Canopus and Mainconcept (Carbon Coder and Digital Rapids respectively) for a pretty substantial workflow.

[poisondeathray]

Thanks zerowalker for recent compile

My general impressions on DVD compliant progressive testing on clean sources:


Overall OK, seems better on gradients that HCEnc

But:
1) Problems with some object edges, there tends to be artifacting, much like DCT ringing. I haven't played with psy settings yet

2) Seems to be some "keyframe" pumping issues, temporal stability issues, tested with open-gop settings. Perhaps I-B-P bitrate allocation settings isn't proportionally ideal yet

[Sparktank]

I'm pretty surprised by the quality for this.

Going from HCenc to x262 2pass+OpenCL, the quality difference is stunning.
I do notice some noise though, for detailed scenes.
Mostly when people are far away from camera (not medium shots or close ups).

I have to agree that gradients are much more better here.
Using cretindesalpes' Dither_package to resize, I'm just blown away by results.

Using parts of old commands I found earlier from this thread for NTSC. (-preset veryslow --tune film)
Added 2passes to target DVD5, changed fps to 24000/1001 with --pulldown 32 (took awhile to realize "32" didn't mean thirty-two).

I was worried at first that --opencl might break, but I guess Nvidia fixed some issues in recent updates.

I've only done 5min samples so far.
I have yet to do a full movie and burn to RW to check for compatibility in players. :devil:

I think I'm going to have some real fun with this and HCenc in the next few days. I quite like the idea of doing x264-like encoding for MPEG-2/DVD.

Thanks for the updated binary. :)

[Lyris]

Sparktank, any idea how it compares to CCE SP3?

[Sparktank]

Sparktank, any idea how it compares to CCE SP3?

I would have to guess with the noise generation, it still has some distance to go.

I do find that creating a lossless intermediate (UtVideo Codec) creates better quality.

I'm not entirely sure which settings have no effect on MPEG2 encoding. But I'm sure toning down some options would improve.

[Sagittaire]

1) Problems with some object edges, there tends to be artifacting, much like DCT ringing. I haven't played with psy settings yet

2) Seems to be some "keyframe" pumping issues, temporal stability issues, tested with open-gop settings. Perhaps I-B-P bitrate allocation settings isn't proportionally ideal yet

If you have the same Rate Control setting than x264, it's easy to solve that ... ;-)

[SuLyMaN]

Is this a good alternative to HCenc?

[Emulgator]

If development continues, yes.

[chiphoi]

Does this software continue development? Im looking forward for this :helpful:

[rwill]

Mine (https://code.google.com/p/y262/) is not ready either... I think mpeg2 is dead.

[Emulgator]

As long as DVDs are sold and have such a wide hardware player base, I wouldn't pronounce MPEG-2 as dead.

We shouldn't forget: every blu-ray player (next generation included) is required to play DVD,
so users will see no need to drop their DVD discs, and so will still buy DVDs as a habit.

I would gladly welcome x262 as an improved alternative, optimized to the max and even donate to have this achieved.

These days I am still asked to make DVDs for maximum compatibility's sake, no matter that I like blu-rays more...

[colinhunt]

It's not dead as long as DVDs are being authored and released commercially. I'm still being asked for more DVD than Blu-ray authoring services.

Like Emulgator, I'd be happy to donate to see x262 development continue.

[SuLyMaN]

Going from HCenc to x262 2pass+OpenCL, the quality difference is stunning.
I do notice some noise though, for detailed scenes.


Hi mate. You have any screenshots/video sample to compare to / as reference? Thanks.
Does it mean its much better than HCenc yet? Or is the noise too noticeable?