[Ffmpeg-devel-irc] ffmpeg.log.20170512

burek burek021 at gmail.com
Sat May 13 03:05:01 EEST 2017

[01:39:37 CEST] <mr_floppy> hello :) Asking straight away: Is there gpu/hardware acceleration support for any lossless video codecs in ffmpeg? (like ffv1)
[01:40:16 CEST] <mr_floppy> (to add: that support real time encoding)
[02:54:40 CEST] <marcurling> Anyone knows how to solve 'Cannot load nvEncodeAPI64.dll' with h264_nvenc under Win7 ?
[03:01:54 CEST] <arog> hi
[03:02:06 CEST] <arog> if I want to write my own C++ app using libav and use x11grab
[03:03:41 CEST] <arog> do I just need to set the input stream to x11grab
[03:03:42 CEST] <arog> and thats it?
[03:25:58 CEST] <DHE> arog: likely you can just follow the examples but force a format of x11grab, an input "filename" of :0.0 or whatever, and other options are specified by the AVDictionary
[09:22:27 CEST] <sinanksu> IMPORTANT : SwfSize parameter available in ffmpeg?
[09:53:00 CEST] Last message repeated 6 time(s).
[16:33:54 CEST] <grault> hi guys.. googled for an hr / read docs, I found nothing which worked.. I _can_ use -segment and -segment_time to save segments from a live stream audio (24/7) .. I also _can_ use showspectumpic to generate a spectrogram.. what I'm looking for is to combine the two.. I just need spectrograms of the segments and I don't need the sound itself.. tried things like this: https://pastebin.com/S9rZYSe8
[16:35:02 CEST] <c_14> I don't think you can combine the segment muxer and the image2 muxer
[16:35:07 CEST] <c_14> pick one
[16:35:18 CEST] <grault> fair enough.. :)
[16:35:43 CEST] <furq> don't you want showspectrum
[16:36:00 CEST] <furq> showspectrumpic apparently generates a single frame for the entire input
[16:37:33 CEST] <grault> furq: that'd be my point.. I need single images of segments of ~20mins of the input... my idea was to use showspectrum and save frames from it..
[16:41:51 CEST] <furq> hmm
[16:42:08 CEST] <furq> showspectrum=slide=fullframe would be perfect if you could set the duration
[16:42:11 CEST] <furq> but i don't see an option t
[16:42:12 CEST] <furq> o
[16:42:13 CEST] <c_14> use showspectrum and a select to take one picture every 20m and throw that in an image2 muxer?
[16:42:29 CEST] <furq> that's not going to have the spectrum of the entire segment though
[16:42:42 CEST] <furq> which i assume is required
[16:42:42 CEST] <c_14> mhm
[16:42:58 CEST] <c_14> write a script and two-pass?
[16:43:06 CEST] <c_14> one pass generates segments, the other uses showspectrumpic?
[16:43:09 CEST] <furq> otherwise you could just use showspectrum,fps=1/1200
[16:43:21 CEST] <furq> and yeah a second pass is the best thing i can come up with
[16:48:10 CEST] <grault> yeah.. feel free to leave it.. I already have a running -segment and another script which polls the filesystem and if there's two output, it processes and deletes the older..
[16:52:25 CEST] <grault> thanks guys
[17:12:13 CEST] <Xys> Hey guys ! I know ffmpeg prints the tbn value from mp4 files. Do you know where this info is stored in the file ? I thought it was in the headerbox, "timescale" but the value I get is different
[17:13:15 CEST] <ritsuka> in mp4 there is a global timescale, and a timescale for each track
[17:14:20 CEST] <Xys> ritsuka : Hm so I was getting the global time scale I guess, and not the tbn from the video track ?
[17:18:25 CEST] <Xys> Does someone know in which box is the tbn value for each mp4 track please ?
[17:19:20 CEST] <ritsuka> mhhd
[17:19:27 CEST] <ritsuka> mdhd sorry
[17:32:40 CEST] <Xys> ritsuka : Thanks a lot !!
[17:47:41 CEST] <Elemental> Hey guys is there a way to set window position with ffplay? I see -x and -y sets window size (which I also need)
[17:51:58 CEST] <Elemental> I'm just trying to display 6 unifi web camera rtsp streams onto a monitor with ffplay
[18:08:50 CEST] <pgorley> dunno, but piping ffplay -h into grep -i position, there's a lot of -x and -y options
[18:13:16 CEST] <Trel> Is there any FFMpeg GUI which will show you the FFMpeg command to be used without actually executing it?  More of a command builder, so for example if I choose "Audio Codec: Copy" from a dropdown, it will show a string get "-c:a copy" added to it?
[18:14:02 CEST] <BtbN> So far all the ffmpeg GUIs I have seen were bad and incomplete
[18:15:20 CEST] <thebombzen> they're always bad and never keep up with the actual development
[18:15:23 CEST] <Trel> Yeah, that's why I'm hoping for one that doesn't actually do anything except build the string
[18:15:27 CEST] <thebombzen> you're better off with just a CLI script to be honest
[18:16:39 CEST] <Trel> That might be something nice to make in python, a command builder.  It could possibly generate options and possible values off an xml which could be updated independently of the script.
[18:17:10 CEST] <Trel> Might be a good project for me to get into python more
[18:19:06 CEST] <BtbN> library users don't build a string, they call the libs directly.
[18:19:31 CEST] <BtbN> But why write an xml to describe the command line, when you can just write the commandline?
[18:19:35 CEST] <furq> why write xml
[18:22:22 CEST] <Trel> Wait, I'm confused what you mean by that.
[18:23:18 CEST] <Trel> I was talk about an interactive script to build the ffmpeg command line. For example a dropdown menu of available codecs.
[18:24:13 CEST] <Trel> What do you mean by they call the libs directly?
[18:24:57 CEST] <furq> he means that a lot of guis don't call the ffmpeg binary, they use the libs
[18:25:03 CEST] <furq> which means there is no command string
[18:25:57 CEST] <Trel> Ah yes, I'm specifically talking about making something where the end result is a ffmpeg command, not actually performing the task.
[18:26:04 CEST] <Trel> For learning, not doing.
[18:26:55 CEST] <furq> just as long as no xml is involved
[18:27:18 CEST] <Trel> The XML was intended to be read by the script for available options
[18:27:30 CEST] <furq> obviously in order to make that you'd need to understand how the ffmpeg cli works, which will obviate the tool
[18:27:35 CEST] <furq> but if it's just for learning then go nuts
[18:27:55 CEST] <BtbN> why make an xml for that, instead of querying the specific lib in question?
[18:28:04 CEST] <furq> what lib
[18:28:14 CEST] <BtbN> The one where the option originates from.
[18:28:48 CEST] <Trel> I'm lost to what you're getting at
[18:29:15 CEST] <BtbN> lavc can tell you which codecs it supports, and what options are available for each one.
[18:29:25 CEST] <Trel> And if that's not installed?
[18:29:34 CEST] <furq> that's part of ffmpeg
[18:29:39 CEST] <BtbN> Then you can't use ffmpeg in the first place.
[18:29:44 CEST] <furq> but yeah in order to do that you'd need libavcodec bindings for python
[18:29:52 CEST] <furq> which is extremely nontrivial
[18:29:53 CEST] <Trel> the hypothetical script does NOT run ffmpeg, it generates a string.
[18:30:08 CEST] <furq> what would be the point of doing that if you don't have ffmpeg installed
[18:30:14 CEST] <BtbN> Hardcoding all the options in there causes it to be outdated within days
[18:30:14 CEST] <Trel> To learn ffmpeg.
[18:30:24 CEST] <BtbN> learn ffmpeg, without having ffmpeg?
[18:30:31 CEST] <Trel> BtbN, exactly, hence the XML with the availale options....
[18:30:47 CEST] <BtbN> makes no sense to me
[18:30:57 CEST] <furq> just do what i did and hang out in here for a few months
[18:31:05 CEST] <furq> soon people will inexplicably think you're an expert
[18:31:06 CEST] <Trel> Not for me to learn...
[18:31:25 CEST] <furq> it worked for me
[18:31:41 CEST] <Trel> I mean the script isn't intended for me
[18:31:48 CEST] <furq> and i didn't even have to write any python
[18:31:49 CEST] <Trel> It's intended as a learning tool for others
[18:32:17 CEST] <BtbN> Why would you learn with some weird external, outdated, script, without being able to verify what you are doing?
[18:32:25 CEST] <BtbN> Just grab an ffmpeg binary and mess with it
[18:32:29 CEST] <furq> if it's for other people then there's no reason to not do what BtbN said
[18:32:52 CEST] <Trel> You try telling a CEO to go chat on IRC
[18:32:53 CEST] <furq> otherwise it'll be outdated on every minor version of ffmpeg and every minor version of every external library
[18:33:05 CEST] <furq> what BtbN said, not what i said
[18:33:16 CEST] <furq> grabbing the options from libavcodec etc
[18:38:43 CEST] <Trel> I'd have to package that with the script :\ my goal is a learning tool, not so much a front end
[18:40:00 CEST] <furq> it's not really a stretch to require that someone using a tool for learning ffmpeg has ffmpeg installed
[18:40:47 CEST] <furq> i'm all in favour of minimising dependencies, but this one is completely sensible
[18:41:15 CEST] <Elemental> Hey guys is there a way to set window position with ffplay? I see -x and -y sets window size (which I also need)
[18:41:37 CEST] <Elemental> or is there a way to do the same thing with ffmpeg?
[18:41:37 CEST] <pgorley> what?! i need ffmpeg installed to learn how to use ffmpeg? preposterous, i say!
[18:41:53 CEST] <Trel> furq, the catch is it's for a CEO who I KNOW doesn't have it.
[18:42:20 CEST] <furq> why does he want to learn it then
[18:42:33 CEST] <Trel> Because he's a CEO and decides if I have a job or not.
[18:42:50 CEST] <Trel> He wants a tool to build the string and nothing more.
[18:43:16 CEST] <pgorley> redirect the output from ffmpeg -h full to a text file and send it to him
[18:43:18 CEST] <furq> it doesn't sound like it'd be that bad if you got fired
[18:43:33 CEST] <Trel> To quote: "so I can learn it by seeing how the options match with what they do"
[18:44:42 CEST] <furq> Elemental: mpv lets you set window position and is generally better than ffmpeg
[18:44:50 CEST] <furq> although your window manager can still override it
[18:45:07 CEST] <Trel> I'm asking for it how he described it.  He wanted to graphically choose options, similiar to how the GUI's work, like selecting a codec, and see exactly what it would change/add to the command line if he were doing it that way.
[18:45:15 CEST] <Trel> If it doesn't exist, I need to try to make it.
[18:46:15 CEST] <pgorley> that sounds like a pita but still feasible
[18:46:48 CEST] <pgorley> can it be a version in particular?
[18:47:48 CEST] <BtbN> Just install Handbrake on his PC?
[18:49:02 CEST] <Trel> BtbN handbrake does the encoding....
[18:49:27 CEST] <BtbN> it calls libav* libraries in the background.
[18:49:45 CEST] <Trel> What good is that for what I need to do....
[18:50:21 CEST] <Trel> I need the end result to look like "ffmpeg -i input_file -c:v codec -c:a codec <other stuff> output_file"
[18:50:27 CEST] <Trel> If it DOES anything, it's not what I need.
[18:50:34 CEST] <Trel> If it doesn't exist, I need to make it
[18:51:27 CEST] <BtbN> Still seems pointless to me
[18:51:40 CEST] <BtbN> you don't learn how to make ffmpeg commandline by having some tool make them for you
[18:51:52 CEST] <BtbN> read the documentation and look at examples
[18:52:46 CEST] <Trel> I learned ffmpeg by reading the docs, you did by experience and examples, the CEO wants to do it by an interactive script or GUI.  Guess which option I need if I don't want myself and my student loan co-signers to be homeless?
[18:53:13 CEST] <BtbN> Seems a bad approach to me.
[18:53:33 CEST] <Trel> I keep agreeing with you, but the end result is the same.
[18:54:14 CEST] <BtbN> Just parse the --help output or something then...
[18:54:24 CEST] <Trel> That's not interactive
[18:54:52 CEST] <Trel> Look, I get it. It doesn't exist.  I need to make it.  I'll throw something together.
[18:55:03 CEST] <BtbN> ...what?
[18:55:13 CEST] <BtbN> Of course it's not ineractive, wouldn't be possible to parse it then.
[18:55:39 CEST] <Trel> The CEO needs an interactive script or GUI, if what you're suggesting isn't an interactive script or GUI, it's not what I need.
[18:55:51 CEST] <Trel> If what I need doesn't exist, I need to make it.
[18:55:57 CEST] <Trel> End result: I need to make it.
[18:56:03 CEST] <BtbN> ./ffmpeg.exe --help full
[18:56:13 CEST] <BtbN> all the options, to every codec, filter, everything
[18:56:20 CEST] <furq> why would you assume a ceo is using windows
[18:56:21 CEST] <Trel> Ok, now where's the dropdown for him to select codecs?
[18:56:24 CEST] <furq> i'm sure he's using slackware
[18:56:35 CEST] <BtbN> the format is not stable, but you're going to be outdated one or the other way.
[18:56:43 CEST] <Trel> -_-
[18:57:33 CEST] <BtbN> no idea why you dislike that, but are all for some crappy hand-written xml
[18:57:47 CEST] <Trel> What do you think the purpose of the xml was in my example?
[18:57:48 CEST] <BtbN> That xml has to come from somewhere, and there are close to 10k options
[18:58:07 CEST] <BtbN> So might as well parse the help full output.
[18:59:16 CEST] <Trel> And where does the script get the output from that command?
[18:59:27 CEST] <BtbN> ?
[18:59:37 CEST] <BtbN> You just run the ffmpeg binary in question.
[19:00:15 CEST] <Trel> Ok, assuming windows, what will my hypothetical script do with "'ffmpeg.exe' is not recognized as an internal or external command, operable program or batch file."
[19:00:47 CEST] <BtbN> complain to the user that he removed the shipped ffmpeg binary...
[19:03:03 CEST] <Trel> What shipped binary....
[19:04:14 CEST] <Trel> You know what, it's really not worth asking sometimes.
[19:04:44 CEST] <BtbN> wtf, that guy
[19:04:51 CEST] <BtbN> Really want to make his life as hard as possible it seems
[21:51:47 CEST] <x-5_zc7_1yta> Hi
[21:52:16 CEST] <x-5_zc7_1yta> I am trying to build ffmpeg on debian but failing miserably
[21:52:22 CEST] <x-5_zc7_1yta> Can you guys help me?
[21:53:17 CEST] <x-5_zc7_1yta> compiling libx264 with config "PATH="$HOME/tmp/bin:$PATH" ./configure --prefix="$HOME/tmp/ffmpeg_build" --bindir="$HOME/tmp/bin" --enable-static --bit-depth=10 --disable-opencl"
[21:53:38 CEST] <x-5_zc7_1yta> and getting error /usr/bin/ld: libx264.a(cabac-a.o): relocation R_X86_64_32 against symbol `x264_cabac_range_lps' can not be used when making a shared object; recompile with -fPIC
[22:00:23 CEST] <x-5_zc7_1yta> As far as I know the problem is related to creating a shared libraries and linking to something static
[22:01:15 CEST] <x-5_zc7_1yta> but why does it try to create something shared when I define --enable-static?
[22:02:27 CEST] <x-5_zc7_1yta> And I am doing pretty much exactly what the compilation guide tells me to
[22:10:40 CEST] <fred1807> any idea how can I get direct link to this stream? https://www.facebook.com/WSL/videos/10154675964302058/
[22:11:04 CEST] <BtbN> try streamlink or youtube-dl
[22:14:43 CEST] <fred1807> no luck with youtube-dl
[22:37:28 CEST] <jgirot> Hello everyone! I have successfully been running version 3.2.4 using hwaccel cuvid and h264_nvenc, but I am having problems using the latest git version.
[22:38:02 CEST] <durandal_1707> what problems?
[22:38:47 CEST] <jgirot> With the -rc-lookahead 32 and -bf 3: No free surfaces
[22:40:01 CEST] <jgirot> Then "Conversion failed!"
[22:40:57 CEST] <thebombzen> full command?
[22:41:39 CEST] <jgirot> ./ffmpeg -loglevel trace -hwaccel cuvid -c:v mpeg2_cuvid -i /dev/shm/rgbtest.ts -c:v h264_nvenc -rc-lookahead 32 -bf 3 /dev/shm/output.mkv
[22:52:38 CEST] <haroldp> I have a working nginx config that uses ffmpeg to convert some crappy IP cams to RTMP for embedding in a web page.  But it sucks and I'd like to switch to Dash or HLS or some such.  Can someone help me update my config for that?
[22:54:23 CEST] <jgirot> If I drop the "-bf 3" it runs fine, but then there's no B-frames in the output
[23:39:26 CEST] <thebombzen> jgirot: you're probably using surfaces for your hardware and software decoder
[23:39:36 CEST] <thebombzen> you should just use ffmpeg's mpeg2video decoder
[23:43:45 CEST] <jgirot> Yes, if I remove "-hwaccel cuvid" it will run without error. My main concern is that this exact command works just fine using v3.2.4
[00:00:00 CEST] --- Sat May 13 2017

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