[MEncoder-users] "requested bitrate is too low." in 2-pass x264 encoding

[Grozdan]

On Sat, Apr 10, 2010 at 6:45 PM, Stroller
<stroller at stellar.eclipse.co.uk> wrote:
>
> On 10 Apr 2010, at 17:03, Grozdan wrote:
>>>
>>> ...
>>> Pardon me, I think I was mistaken.
>>>
>>> I think that MP4Box is supported by my distro (Gentoo), but that undvd
>>> used
>>> mpeg4ip or mp4creator, and it is the remuxer that undvd used that was
>>> depreciated.
>>
>> Yeah, undvd uses mp4creator which is officially dead for some time.
>> There is a fork of it somewhere, but I don't know much about it. I
>> don't know why he chose to use it instead of mp4box, as the latter not
>> only is active but also supports much more options than mp4creator
>
> I had some discussions with the author, and he wasn't really interested in
> .mp4.
>
> When I initially used it it outputted only .avi files (IIRC) and these play
> file on mplayer, which the author used and was perfectly happy with. But
> IIRC they were an invalid format due to the audio codec used, and wouldn't
> play on my Mac.

AVI is not recommended to be used as permanent container for h264
video. This is due to a few things, like the way h264 stores frames
(b-frames and such, also a few other things) and due to no
standardized "agreement", which means every single app can store h264
video in AVI as it likes, resulting in incompatibility. It can e used
as intermediate container, though, and that's what h264enc uses, but
don't ever use it to permanently store/archives your videos in it if
you encode to h264.

>
> Additionally, I use a PS3 to play back .mp4 files, so I was quite  happy
> when he added mp4 support. However with the death of mp4creator undvd's
> author wasn't interested in fixing mp4 support again, which made it useless
> to me.
>
> I compiled a local copy of mp4creator, but it's obviously something I don't
> want to continue supporting - I would rather take on a whole wrapper-script
> project from scratch, than be using an old mp4creator and constantly in fear
> that mplayer would break the old version of undvd I would be reliant upon.
>
>> Also, the x264 options in undvd are pretty bad, last time I looked at it.
>
> Would you care to clarify?

I haven't looked at it for a long time, but last time I checked, he
only used subq=5, no bframes and a few other important things weren't
enabled as well (like 8x8dct, iirc). But x264 got improved too and
some of the things are now enabled by default so undvd not enabling is
not a problem now. Still, from quality POV, his x264 can be improved
by a good amount.

>
> ISTM that this is something that can be fixed.
>
> The things I really appreciate about undvd are scandvd (shows length of
> titles, subtitles & audio tracks), coloured output, and it's auto-cropping
> of the  black bars (which is a little clever, I think; I think it always
> ensures the frame size is divisible by 16, or whatever is appropriate).
> Also: that it's simple, and doesn't push too many options upon me.

..... is what h264enc also does and supports

>
> It annoys me that I have to set quality in undvd by choosing a target file
> size (instead of just settings a BPS, which would be more useful), and that
> I must tell it not to rescale the video to a smaller frame size. But again,
> these faults are easily fixed / overcome.

What is BPS? Do you mean BPP( bits per pixel)? If so, you should NEVER
EVER rely on BPP for this as it's just a terrible metric

>
> Whatever commands one passes to mplayer / mencoder, I notice that I'm not
> alone in appreciating scandvd (mentioned by Laine Lee in his post of 10
> April 2010 05:12:52 BST).
>
>> I can probably patch undvd at some point, but if you're willing to do
>> it, have a go.
>
> I don't know whether the answer is just to make minor patches or start again
> from the ground up. I have a much better ability to read perl now, which I
> really didn't have at the time mp4creator was removed from my distro's
> repository, so I can perhaps asses this. I do want to make the time to do
> some programming this year, but that may be difficult, as I am better at
> procrastinating.

Whatever you think is better, but as said, I'm not really interested
beating on a dead horse. You can probably take some ideas and code
from it, though, and go from there if you want to start a new project
based on it.

>
>> I'm not really interested in undvd, though. It's a very
>> simplistic tool as an interface, but also a dumb one.
>
> On the other hand, your h264enc just makes me go "WTF!?! all these options!
> what do they do?" With undvd I set it to crop, not to down-scale, and I set
> a target file size, and I would get a rip that was almost indistinguishable
> from the original DVD (and which would play on my PS3).

Why? and when was the last time you used h264enc? I can pass through
it in less than 40 seconds. Most options are grouped under submenus so
if you don't need postprocessing for example, you can skip the whole
main menu and you don't even have to answer with "y" or "n" as the
script always defaults to "n" if no answer is given. Simplistic tools
like undvd are nice, but on the other hand, the video world is not so
simple and often requires some form of pre/posprocessing (IVTC,
deinterlace, FPS conversion, whatever) so that's where it stops for
undvd. It doesn't even support deinterlacing, yes?

>
> After some experimentation I determined that my optimal file size for
> ripping the 170 minute movie Heat was 2gig, and made target sizes relative
> to this. Clearly it would be better simply to choose a BPS to rip to.
>
> Unfortunately, h264enc's presets are little use to me, because they're
> already too complicated for me to choose one in the first place (or were, at
> least, last time I tried it - perhaps 1 year ago).

How are they complicated? h264enc presets one time were even praised
by Jason (x264 dev) and by a lot of users I interact with. What is so
complicated in them? you just choose the preset you want, ie if you
need to encode for the ipod or something, choose one of the 4 ipod
preset available and that's it. If you're going to encode for watching
on PC, just choose one of the standard PC presets, preferably one of
the high qualities presets like vhq, ehq or uhq. That's all.

>
>> It can't handle anything but PAL content, last time I checked.
>
> Interesting, I'm not sure that I checked this. I live in the UK and have a
> mixed collection of PAL & NTSC DVDs, but I have a US PS3 - that is
> region-locked to NTSC playback. My main use for undvd was to rip my PAL
> disks, therefore, so the .mp4 rips could be played on the PS3 (streamed
> using MediaTomb). In many ways it would be easier for my just to buy a £20
> PAL DVD player, but that would be an admission of defeat. ;)

Well, NTSC is kinda a double edged sword. If it's soft-telecined (most
are) then you can ignore it and just force the output fps to 23.976.
But if it's hard telecined or mixed progressive & telecine, then you
need to do some IVTC on it. With undvd, you can't do any of those,
afaik. And as the author said, he wrote it mainly for him and his
needs so it's safe to assume he didn't bother about all of the above,
which is important for a lot of people.

>
>> There's a similar
>> script called abdvde (on doom9 forum) which is much better than undvd,
>> but it only outputs to MKV container (afaik)
>
> Thanks, I'll bear that in mind. It will be some weeks (at least) before I
> have the time to investigate this.
>
> Stroller.
>
>
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