[Ffmpeg-devel-irc] ffmpeg.log.20160117

burek burek021 at gmail.com
Mon Jan 18 02:05:01 CET 2016

[00:08:35 CET] <xintox> yo
[07:17:06 CET] <shadow42085> i cant seam to get past libass in my ./configure setup here http://pastebin.com/3AdNceaL and everthing I have tried the lastest source cant find libass
[07:18:28 CET] <shadow42085> yes I am cross compiling it and when I installed it in linux it build just fine so what gives
[07:19:02 CET] <shadow42085> or am I in the wrong channel?
[07:19:34 CET] <c_14> Can you pastebin your config.log
[07:19:37 CET] <c_14> ?
[07:22:08 CET] <shadow42085> one sec
[07:23:51 CET] <shadow42085> http://pastebin.com/TCz0cPMT
[07:25:09 CET] <shadow42085> i also did pkg-config --libs libass it posted -lass
[07:25:27 CET] <c_14> I assume libass.so is located in /usr/local/lib?
[07:26:10 CET] <shadow42085> correct
[07:31:40 CET] <c_14> If you remove --enable-libass it builds correctly?
[07:31:51 CET] <shadow42085> let me check
[07:33:27 CET] <shadow42085> what the heck now its saying libfdk_acc is not there which I not it is
[07:33:27 CET] <c_14> I think the problem is that you probably didn't cross-compile any of the dependencies
[07:33:48 CET] <shadow42085> ok how do I cross-compile those
[07:34:30 CET] <c_14> Mostly the same way you would ffmpeg. If they have configure scripts it's usually --arch= --target-os= --cross-prefix= etc
[07:35:00 CET] <c_14> some might have --host though
[07:35:19 CET] <c_14> https://trac.ffmpeg.org/wiki/CompilationGuide/CrossCompilingForWindows
[07:35:40 CET] <c_14> Doesn't have a lot of info directly, but you can check the scripts for how they compile the deps and then compile yours like that as well.
[07:38:30 CET] <shadow42085> ok so I have to get all of the depends
[07:38:30 CET] <shadow42085> alot of them i installed via apt in debian
[07:38:31 CET] <shadow42085> well thanks off to the repos to get them
[07:45:43 CET] <shadow42085> yea thanks
[08:24:28 CET] <WereCatf> I have a device streaming video from a camera with mjpg-streamer and I want to record the output at various points to a file using ffmpeg. I tried 'ffmpeg -i
[08:24:32 CET] <WereCatf> Ugh
[08:25:16 CET] <WereCatf> 'ffmpeg -i http://server.url/?action=stream -an -vc copy out.mkv' and while the file works its timing is off
[08:25:40 CET] <WereCatf> When playing the file back the frames are being played at super-speed
[08:26:12 CET] <WereCatf> How could I make ffmpeg save the stream with proper frame-timings?
[08:34:29 CET] <WereCatf> Oh, and it apparently doesn't copy the video when doing it like that.. when viewing the video VLC says it's H.264 when it's supposed to be mjpeg
[08:36:29 CET] <zap0> i have   ffmpeg -i file.flv -b 400000 out.mp4       i thought that was suppose to limit it to 400 kb/s ?     after conversion the file got bigger, not smaller, and it's reporting the bitrate as 517kb/s
[08:58:50 CET] <c_14> WereCatf: -c copy as an output option and -framerate <something> as an input option.
[09:00:07 CET] <c_14> zap0: does the file have audio? Also you might want to use 400k as it's easier to read
[09:01:28 CET] <zap0> c_14, yes it has audio.... i doubt the audio grew..  without specifying audio.. does it not just copy it?
[09:01:45 CET] <c_14> ye
[09:01:53 CET] <c_14> unless you explicitly tell it to copy it will reencode
[09:07:15 CET] <WereCatf> c_14: Mm, yeah, specifying framerate doesn't work. But I guess I'll just live with that..
[09:08:08 CET] <c_14> WereCatf: try -r instead of -framerate?
[09:08:17 CET] <WereCatf> c_14: tried both
[09:08:22 CET] <c_14> Did you put it before -i ?
[09:08:27 CET] <WereCatf> Aye
[09:08:32 CET] <c_14> hmm
[09:14:02 CET] <WereCatf> Can ffserver accept an mjpeg-stream from a USB-webcam and stream it forward without doing transcoding in-between? Or does it only support uncompressed input from a webcam?
[09:14:24 CET] <c_14> you can use -override_ffserver, theoretically at least
[09:14:38 CET] <c_14> (and then specify -c copy on the ffmpeg commandline)
[09:14:47 CET] <c_14> I wouldn't recommend using ffserver though
[09:15:04 CET] <WereCatf> Why?
[09:15:45 CET] <c_14> It's hard to use, not very well documented, and not very well supported.
[09:16:02 CET] <WereCatf> Well, ffmpeg is hard to use as well :D
[09:16:59 CET] Action: c_14 got used to it, might just be Stockholm Syndrome
[09:17:16 CET] <c_14> Also the docs are usually decent and you can often find someone with the knowledge to help you.
[09:18:11 CET] <c_14> The percentage of ffserver questions that receive answers in this channel is very, very low.
[09:18:42 CET] <WereCatf> I suppose people use some other streaming-solutions, then
[09:19:09 CET] <c_14> usually yes
[09:19:41 CET] <Betablocker> hihi
[09:20:34 CET] <WereCatf> Oh well, I'm not particularly familiar with streaming-schemes and such. I just have this project where I have a very low-end OpenWRT-router (400MHz ARM CPU) that I'd like to use as a streaming webcam-server. Streaming mjpeg from the camera without transcoding with, say, mjpg-streamer, takes only like 10% CPU even on those specs
[09:21:03 CET] <WereCatf> And I'm just kind of wondering to how to best record the stream on another computer at will, or if there's a better way of streaming it
[09:21:56 CET] <Betablocker> you could try our tool&. - dont want to be spammy but it could fit for your case &. query ?
[09:22:04 CET] <Betablocker> WereCatf:  &  ^
[09:22:17 CET] <WereCatf> I have no idea what tool you're talking about
[09:23:04 CET] <Betablocker> take a look query
[09:23:25 CET] <Betablocker> 1:1 chat in some window in your chat client& :)
[09:24:32 CET] <Betablocker> its open source & so its a deeper view worth if you need streaming with ipcameras / raspberrypi camera board or usb camera& to be honest for usb cameras it is oversized &
[10:50:04 CET] <sgo11> hi, I have h264 video file. but the fps is incorrect. how can I just change the fps value without decoding/encoding etc..? I just don't want the quality to change. sometimes, re-encoding will lose the quality of a video file. thanks a lot.
[10:53:37 CET] <fritsch> sgo11: how wrong is it?
[10:53:53 CET] <fritsch> post a mediainfo of that file, please
[10:54:03 CET] <fritsch> to a pastebin near you
[10:55:34 CET] <sgo11> fritsch, will "ffprobe -show_streams" be enough?
[10:56:32 CET] <sgo11> fritsch, http://pastebin.ubuntu.com/14543542/
[10:57:38 CET] <sgo11> fritsch, I created this video file with the following command in raspberry pi 2: `raspivid -t 10000 -o test06.h264 -w 1080 -h 1080 -fps 15`
[11:15:20 CET] <sgo11> Since I created the file with the option -fps 15, I think it should be 15fps unless the program raspivid has a bug. I don't know why .h264 will always play in 25fps. Is that because raspivid program does not set proper fps value to the mediainfo of the file?
[14:12:34 CET] <relaxed> sgo11: ffmpeg -framerate 15 -i input.h264 -c copy output.mkv
[14:13:53 CET] <JEEB> huh, I don't think I've had that ever work for me?
[14:14:08 CET] <JEEB> did that actually give you the according PTS?
[14:14:14 CET] <JEEB> if yes, cool
[14:14:30 CET] <JEEB> I've always used L-SMASH's muxer or something for the initial "change-the-rate" step
[14:14:37 CET] <JEEB> and then remuxed that mp4
[14:16:06 CET] <sgo11> relaxed, thanks for that. I am using "MP4Box -fps 15 -add video.h264 video.mp4" for now. and it works very well. I will try that command later.
[14:21:28 CET] <relaxed> JEEB: it doesn't work :(
[14:21:40 CET] <JEEB> yeah
[14:21:54 CET] <JEEB> sgo11: ewww GPAC :/
[14:28:32 CET] <sgo11> JEEB, :)
[20:22:26 CET] <octal> Hi. I was wondering if, given a static, fixed video shot on a presentation wall, where a presenter is using a laser pointer, if it is possible to convert everything to alpha = 100% except the laser pointer
[20:23:02 CET] <ChocolateArmpits> octal: that's what keyers do
[20:23:56 CET] <octal> hi, ChocolateArmpits: the goal is to take the red point and place it into the original slides taken from the PDF instead of the wall.
[20:24:43 CET] <ChocolateArmpits> octal: can you estimate how much contrast there is between the pointer and the wall? Like how saturated is the point compared to the wall, how bright it is?
[20:25:47 CET] <octal> ChocolateArmpits: it will vary, as the wall has some bright light reflections, unfortunately
[20:26:13 CET] <ChocolateArmpits> well what about the color? Is the wall white ?
[20:27:22 CET] <octal> ChocolateArmpits: the wall is pretty much uniformly white, yes, over which there is a projection, over which there is the pointer
[20:27:48 CET] <ChocolateArmpits> well the projection makes it harder
[20:28:27 CET] <ChocolateArmpits> You should to extract the red channel and then apply contrast until everything but the pointer is black
[20:28:33 CET] <ChocolateArmpits> try to*
[20:28:54 CET] <ChocolateArmpits> then you will get a b&w mask that can be used on a red matte
[20:29:30 CET] <octal> ChocolateArmpits: is it possible to 'subtract' one frame from another, so I can subtract the explanation with pointer from the frame without pointer?
[20:29:44 CET] <octal> ChocolateArmpits: is it too crazy?
[20:30:59 CET] <ChocolateArmpits> octal: image processing usually has a subtract or difference operation
[20:31:33 CET] <ChocolateArmpits> there's even a special key called difference key
[20:31:45 CET] <ChocolateArmpits> that masks one image against another in Blender
[20:33:00 CET] <ChocolateArmpits> ffmpeg isn't exactly the most intuitive thing for these types of processing
[20:33:09 CET] <ChocolateArmpits> You should try Blender or Natron
[20:33:23 CET] <ChocolateArmpits> Natron might be more friendly
[20:35:00 CET] <durandal_1707> there is colorkey and chromakey
[20:35:16 CET] <durandal_1707> filter in ffmpeg
[20:35:53 CET] <durandal_1707> and then is blend filter
[20:42:43 CET] <yans> Hi! I got a simple question how to add subtitles to .avi but 1:1 copy without changing format file and quality? ffmpeg -i myfile.avi -vf subtitles=myfile.srt -vcodec libx264 -acodec libfaac myfile.avi should be enough for it? i dont want to use -crf to change quality of movie, so how to do it correctly?
[20:43:21 CET] <yans> sry "-acodec copy" of course
[20:43:55 CET] <furq> there's no way to reencode without specifying the quality
[20:44:03 CET] <J_Darnley> Of course not
[20:44:13 CET] <furq> hi buddy
[20:44:18 CET] <J_Darnley> hello again
[20:44:26 CET] <yans> ok, but i want to have same file storage like before
[20:44:47 CET] <furq> then remux it into a container that can handle soft subs
[21:00:50 CET] <octal> ChocolateArmpits: thanks for the tips, I will check them out.
[21:02:23 CET] <yans> k, thx
[21:16:17 CET] <wCPO> Can I with ffmpeg check if source file for a encode is X file? or do I need to write my own logic?
[21:19:16 CET] <fritsch> wCPO: sorry, i could not parse your question, please try again
[21:19:56 CET] <wCPO> fritsch, do ffmpeg save some sort of "checksum" in the output file. So I can check if x file was the input?
[21:20:17 CET] <fritsch> not to my knowledge
[21:20:31 CET] <fritsch> especially not if audio / video gets processed
[21:22:00 CET] <J_Darnley> The closest you can probably get is flac which stores the md5sum of the audio dtaa given to the encoder.
[00:00:00 CET] --- Mon Jan 18 2016

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