[Ffmpeg-devel-irc] ffmpeg.log.20180106

[burek]

[00:07:19 CET] <aokfire> not working :(
[00:07:25 CET] <aokfire> -vf "crop=1920:1078:0:0, scale=1280:-2"
[00:07:29 CET] <aokfire> did I do that right...?
[00:07:48 CET] <aokfire> output is 1080 still
[00:08:07 CET] <aokfire> ffmpeg version N-89508-g1f1207145a
[00:12:57 CET] <aokfire> https://ghostbin.com/paste/exn9m/raw
[00:14:08 CET] <relaxed> -vf "yadif=1, crop=1920:1078:0:0, scale=1280:-2" and lose the second -vf
[00:20:34 CET] <aokfire> yes, that works!!! almost...
[00:20:41 CET] <aokfire> It's cropping from the bottom, not the top for height haha
[00:20:45 CET] <aokfire> but it is cropping properly!
[00:24:41 CET] <relaxed> I believe that should start at the top, left position and crop the top two lines
[00:25:05 CET] <aokfire> if I modify to crop say 100px, it's visibly cut on the bottom
[00:26:12 CET] <relaxed> I'm wrong :/
[00:27:22 CET] <aokfire> sorry, not to imply that! I don't know, maybe :S
[00:27:25 CET] <aokfire> sorry
[00:27:55 CET] <relaxed> it starts from the bottom, left :)
[00:29:18 CET] <aokfire> oh
[00:36:14 CET] <furq> it's output width, height, position of left edge, position of top edge
[00:36:56 CET] <furq> so the fourth arg would need to be 2 to crop 2 off the top
[00:37:30 CET] <furq> also -threads 4 before -i doesn't affect how many threads x264 uses
[00:37:38 CET] <furq> it's a decoder option if you put it before -i
[00:37:53 CET] <furq> but you shouldn't set that unless you have a good reason to
[00:40:03 CET] <relaxed> oh!
[00:48:36 CET] <aokfire> furq, so you say I shouldn't set more threads?
[00:48:41 CET] <aokfire> or just don't touch it at all, and thanks for the crop info]
[00:49:14 CET] <aokfire> and so say I wanted to crop from top AND bottom, would I set 3rd arg as bottom px, and 4th as top?
[00:53:29 CET] <aokfire> As well, how do I use the "exact" function of crop?
[00:55:20 CET] <furq> i forget what exact actually does
[00:55:37 CET] <furq> but your output is 4:2:0 anyway, so your output height has to be mod2
[00:55:53 CET] <furq> if you do want to enable it then crop=1:2:3:4:exact=1
[00:56:32 CET] <aokfire> dang, it's actually only 3px needed but guess I'm forced to use 4
[00:57:34 CET] <furq> if you're scaling afterwards then you should be able to use 3
[00:57:48 CET] <aokfire> scaling is 1280:-2
[00:57:51 CET] <furq> right
[00:58:02 CET] <aokfire> should I force it to do 1280:717?
[00:58:27 CET] <relaxed> libx264 expects mod2 too
[00:58:31 CET] <furq> no
[00:58:37 CET] <furq> crop 3px off and then scale to 1280:-2
[00:59:04 CET] <furq> the AR will be slightly off either way, but not by a perceptible amount
[00:59:31 CET] <durandal_1707> exact is for cropping non power of subsamplings, for only limited use
[00:59:42 CET] <aokfire> oh
[01:00:35 CET] <furq> durandal_1707: i take it you'd need that in this case
[01:01:06 CET] <durandal_1707> if x y is even it should be ok
[01:01:07 CET] <aokfire> crop=1920:1077:0:3:exact=1, scale=1280:-2
[01:01:19 CET] <aokfire> doesn't look even
[01:02:07 CET] <aokfire> Stream #0:0: Video: h264 (libx264), yuv420p, 1280x718
[01:02:09 CET] <durandal_1707> you cant crop then without getting wrong output, you need resample frame
[01:02:52 CET] <aokfire> How would I do that?
[01:03:47 CET] <aokfire> https://trac.ffmpeg.org/wiki/Scaling ?
[01:04:07 CET] <durandal_1707> by upscaling only chroma croping  it and than downscaling it back....
[01:04:15 CET] <durandal_1707> just theory
[01:04:22 CET] <aokfire> sounds like more work than it's worth lol
[01:04:38 CET] <furq> do you actually need to do that if you're scaling afterwards
[01:04:41 CET] <aokfire> sounds easier and less hassle for anyone involved to either 2px and leave a thin bar, or just 4px and move on with our lives lol
[01:04:49 CET] <aokfire> just my thoughts
[01:05:33 CET] <furq> i normally just overcrop so i've not thought about this much, if it wasn't evident
[01:05:38 CET] <furq> but then i normally don't scale afterwards
[01:05:53 CET] <furq> i would have expected that to work
[01:07:20 CET] <aokfire> I tried it, with line above, and it doesn't seem to
[01:07:32 CET] <aokfire> as much as I want to strive to try and get it right, it's just less hassle to overcrop
[01:07:46 CET] <aokfire> also, still curious what you mean by "you don't need to use -threasd" furq?
[01:07:50 CET] <aokfire> "threads"
[01:08:52 CET] <furq> x264 autoselects the right number of threads
[01:09:12 CET] <furq> which is logical cores * 1.5
[01:12:43 CET] <aokfire> ok, sounds good. i'll remove it
[01:35:57 CET] <aiena> I have a video stream with a few frames in the negative range e.g. some frames are there between -2 and 0 seconds I want to shift them forward can I do that with ffmpeg without re encoding?
[01:38:02 CET] <aokfire> thanks for the help everyone, gotta go :)
[03:39:31 CET] <Durandal> Does anyone know what OggOpus encoders are currently available?
[03:39:44 CET] <Durandal> As in, the specific code that deals with containerizing opus packets into an ogg file, not the codec itself
[03:39:59 CET] <Durandal> There's libopusfile and then I assume ffmpeg has its own thing
[03:40:41 CET] <furq> it does
[03:43:20 CET] <Durandal> I bring this up because libopusfile is only like 3 months old, so did everyone before that use ffmpeg or was there something else?
[04:03:02 CET] <furq> i'm pretty sure libopusfile is way older than that and also that's a demuxer and decoder
[04:03:13 CET] <furq> muxing is presumably just libogg
[06:59:09 CET] <JC_Yang> 3.4.1 built for arm with neon+thumb enabled can crash the program by SIGILL, is it known? disable either thumb or neon works, of course, test in a Cortex A17 with full neon support
[13:18:23 CET] <Fyr> guys, how can I add multilingual chapters, like MakeMKV does?
[13:19:07 CET] <Fyr> the FFMPEG manual explains only addition of single-lingual chapters.
[13:20:58 CET] <Fyr> it's called multiple chapter names in MKV specifications.
[14:38:42 CET] <mosasaur> I'm trying to convert hevc (native) -> h264 (libx264) but it hogs my old laptop's CPU, any hints or other codecs?
[14:51:02 CET] <mike_check> mosasaur: did you try scaling down the output quality?
[14:54:42 CET] <mosasaur> mike_check: I'm doing -crf 30
[14:55:48 CET] <mosasaur> speed is still 0.34
[14:58:37 CET] <mosasaur> if I move to DO the same thing is immediately killed :(
[15:24:31 CET] <mike_check> mosasaur: maybe try halving the input framerate?
[15:25:25 CET] <mosasaur> mike_check: thanks for the tip, I will look into it
[16:05:31 CET] <CrazyLemon> hey guys.. i'm using ffprobe but i can't find any option how to just get "Metadata:      service_name    : XYZ      service_provider: YZX"  - grep is an option but i'd rather not use it if its not necessary :)
[16:10:48 CET] <mike_check> CrazyLemon: what are you looking to grab the meta from?
[16:12:40 CET] <c_14> CrazyLemon: -show_entries format=tag:service_name maybe
[16:13:23 CET] <c_14> check -show_format if it's there
[16:15:01 CET] <CrazyLemon> mike_check from a url (mpegts)
[16:17:37 CET] <CrazyLemon> https://paste.sh/AHfgOMq4#TCPBHkkaIFIvxwnlIVNEtiSv        this is what i get..
[16:17:56 CET] <CrazyLemon> c_14 its not in show_format its just outside it :D
[16:18:38 CET] <c_14> >Decryption failed (Invalid hash, ensure you have the full URL, including the full '#xxxx' part at the end)
[16:19:25 CET] <c_14> ah, now it works
[16:20:56 CET] <c_14> I mean, you can try -hide_banner -of json and then parse it as json
[16:21:16 CET] <c_14> as an alternative to grep
[16:21:26 CET] <c_14> But I don't think there's an option to only output that then
[16:21:53 CET] <CrazyLemon> c_14 i'll just use grep then.. thanks for the help :)
[17:35:53 CET] <Spring> reading this thread a user mentioned that HDR to SDR tone mapping isn't necessarily a 'set it and forget it' type function. So I wouldn't be able to use it for ex. on a feature-length video? https://forum.doom9.org/showthread.php?t=175125
[18:39:04 CET] <Spring> will be back maybe tomorrow
[20:37:23 CET] <Keano> Hi there. Anyone know if it is possible to add camera shake in ffmpeg?
[20:38:56 CET] <therage3> interesting question. I'm googling and I can only find the opposite of the desired effect: the _removal_ of camera shake, heh
[20:41:45 CET] <Keano> Indeed. I found the same!
[20:43:03 CET] <Keano> I've got a pre-recorded film with camera shake in it, and I want to shoot new footage and carry the 'effect' over
[20:44:10 CET] <sfan5> this might sound stupid, but why not shake the camera while shooting new footage?
[20:46:17 CET] <Keano> hah, the environment i'll be shooting in won't allow for it
[20:46:34 CET] <Keano> I did find this, perhaps with some tweaking on the numbers can achieve it? https://www.youtube.com/watch?v=yBDwFdsKeow
[22:15:10 CET] <esspapier> so, I assume when using concat there is not some flag that marks each source video as a chapter on the destination video, right?
[00:00:00 CET] --- Sun Jan  7 2018