Fake Programmers

cpast

00:39

question

i just flagged a not an answer

it should have been an edit to the question

but it also needed cleaning up, so i suggested an edit that cleaned up the text

was that what i should have done, or should i have waited until it was merged into the post?

this question: superuser.com/questions/548871/…

wait, wrong room

sorry

evilsoup

18:27

@slhck hey, so I got around to taking a proper look at that table of codecs etc

I see that you've added in stuff about mpeg1,2 etc

(which was going to be my first suggestion)

It does seem weird to have prores there, since it is an intermediary production codec, whereas everything else listed there is a delivery codec

I would have thought that a separate table/guide for intermediary codecs would be more orderly (you'd also want DNxHD, DV, maybe mention huffyuv

Also, if you're going to mention MPEG2, you should also probably add in AC3 audio - which is commonly used on DVDs alongside MPEG2 - as the most common use-case for MPEG2 in ffmpeg is probably creating DVD-compliant VOB files.

Unfortunately, AFAICT, AC3 doesn't have a VBR mode, so it may not fit properly there

Apart from that, the only omission on the list is the new Opus encoder; but that's very new, and I haven't got to play with it yet, so I'm not entirely sure how it's supposed to work

slhck

18:42

@evilsoup Yeah, I could move the intermediate codecs in a separate table. Haven't checked out DNxHD really, just for decoding. And that only with ffmbc.

I'll definitely have to check out Opus at some point.

evilsoup

18:56

I've actually been working on a blog post (to later be incorporated into the ffmpeg wiki, when I think it's up to scratch) that covers very similar ground to your table. I'll put up the WIP and give you a link, there may be something in there that you can use.

slhck

@evilsoup Oh, that sounds nice. I definitely wanted to move the info to the wiki at some point, but if you have something already…

@evilsoup Just curious, do you have your own blog? Or for Super User?

evilsoup

I have an empty blog set up, just for this post (and a few other|)

mostly just as a staging point, so I can push out the information somewhere people can see

but before I consider it ready for the ffmpeg wiki

your table is a nice summary of the information, though

slhck

Ah, I see

Thanks :)

evilsoup

oh actually, there's one more thing

with x264, you probably should mention the presets, since they're just as important in controlling file size as the crf

slhck

19:14

@evilsoup True. I'll add a note.

evilsoup

here you go; I don't think it has any information you don't have, but if you have any criticisms of it they'd be nice to hear :)

slhck

19:30

Section 1 could mention that this is more or less a "VBR" mode, since many people are familiar with the approach from MP3.
You mention "MPEG4 part 2/Divx/Xvid", but the encoders (Divx/Xvid) should probably go into parentheses.
Maybe you could mention that there's a huge difference between a (theoretical) codec and an (actual) encoder as well as what's a codec vs. a container. You can steal here if you like: http://superuser.com/questions/300897/ — unfortunately, many people get confused by these terms.

Otherwise a nice post so far. Very concise!

I often link to something I found on the Handbrake wiki (and Wikipedia), which has now been deleted there. It explains what "Constant Quality" encoding is and why it's useful: homepage.univie.ac.at/werner.robitza/crf.html — maybe we can move this into the FFmpeg wiki at some point. Nobody seems to have any copyright on this.

evilsoup

well I'm glad that those are relatively minor corrections, and I will definitely incorporate that stuff into the next version

slhck

You could add a note about AVI not properly supporting bi-predictive encoding. One of the reasons H.264 won't work.

evilsoup

maybe migrate that crf stuff over to the x264 encoding guide on the ffmpeg wiki, since it's x264-centric

slhck

And H.264 is with a capitalized h – nitpick, sorry :)

evilsoup

it's all good, count the pennies & the pounds count themselves :)

slhck

19:36

@evilsoup I could probably do that, yeah… add a sub-page there or something.

Comparison of container formats

This table compares features of container formats. To see which multimedia players support which container format, look at comparison of media players. Information {| class="sortable wikitable" border="1" cellpadding="1" cellspacing="0" style="font-size: 85%; text-align: center; width: auto" |- !Name and file extension, if different !Proprietor/Developer !License !Variable bit rate audio !Variable frame rate !Chapters !Captions (Subtitles) !Video formats supported !Audio formats supported !Metadata/Tags supported !Menu Support (like DVD) !Streaming Support !Attachment Support !3D Support (...

^--- always a good reference

evilsoup

groovy

slhck

Nice, they added an Opus column already.

evilsoup

the only thing for the crf info: if you copied it from wikipedia, I believe that you have to cite them as the creator

slhck

The page on Wikipedia was a verbatim copypaste of the Handbrake wiki.

evilsoup

hmm

slhck

19:38

And it's now deleted.

I managed to scrape the text from the Wayback Archive.

evilsoup

well I guess it depends what the handbrake wiki's policy is

copyright doesn't end just because the text is deleted from the internet

slhck

True

evilsoup

I mean, I'm sure they wouldn't mind, since both HandBrake and FFmpeg are FOSS projects

but better safe than sorry, you know?

slhck

You're absolutely right

Hm, their wiki doesn't say anything about usage rights.

evilsoup

that is annoying

well, HandBrake itself is GPL

I don't think that strictly applies to the information in the wiki; but on the other hand I seriously doubt that anyone is going to go after you or me or the FFmpeg wiki for copying over a deleted guide from there freely-available wiki,

so I say, just go for it

slhck

19:58

fair enough :)

evilsoup

maybe put in something along the lines of 'this information was originally taken from the HandBrake wiki, but has since been deleted from there'

slhck

Yup. Did the same on my homepage, actually.

evilsoup

ace

slhck

Hey, thanks a lot for the feedback.

evilsoup

thank you for the feedback on my stuff, too :)

slhck

20:02

Heh. Just noticed… Did we answer the subtitle question at the same time?

evilsoup

lol probably

actually, the timestamps are saying that you answered first

slhck

Yeah… I had deleted it for a short time after I found out that FFmpeg doesn't automatically choose mov_text but just fails.

evilsoup

heh

hmm

actually, that sounds like a potential bug

you should file it on the ffmpeg bug tracker

slhck

Stream mapping:
  Stream #0:0 -> #0:0 (copy)
  Stream #0:1 -> #0:1 (copy)
  Stream #1:0 -> #0:2 (subrip -> ?)
Encoder (codec none) not found for output stream #0:2

ah wait

no, nvm, it's definitely a bug

But then I'd have to compile it here to check the latest Git HEAD. And compiling sucks on OS X. Gotta switch to my Linux box later.

evilsoup

well, I'm due to compile it myself (for opus & drawtext support) anyway, so if you want I can test it out later today/some time tomorrow

slhck

20:11

Sure, that'd be great. All I did was -i in.mp4 -i in.srt -c:v copy -c:a copy -map 0 -map 1 out.mp4

evilsoup

man, all this good stuff is going to get lost in the general chat, I should have opened up a separate room for this conversation

slhck

You can bookmark it though if you like. And nobody uses this room anyway, except for @IvoFlipse :P

Ivo Flipse

@slhck Exactly, this is my room :P

slhck

@evilsoup ffmpeg.org/trac/ffmpeg/ticket/2260

I just created it anyway.

evilsoup

20:31

oh whoops, sorry I assumed it was a general-use room :P

slhck

Oh, it is, it's just less active

Ivo Flipse

20:45

Man, why can't people in biomechanics publish in Open Access journals :(

slhck

20:56

@IvoFlipse Actually never read anything from an OAJ, IIRC

Ivo Flipse

Well I simply can't find anything :(

Well that's not true, I can find them, I just can't read them

slhck

Do you need anything downloaded?

Ivo Flipse

I need lots downloaded :P

slhck

Send me links if you want, I'll send the docs to you.

Ivo Flipse

Thanks, might hold you up to that once I get desperate

My client was supposed to sent me a collection, but haven't received anything yet

slhck

20:58

Meh. Waiting for clients.

Ivo Flipse

I managed to find about 200 articles through Google-fu

Well if they make me wait, I make them wait

slhck

A bug, on our Meta, that was fixed within 24hrs? meta.superuser.com/questions/6337/…

status-cantbelieve

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