[Ffmpeg-devel-irc] ffmpeg.log.20150612

[burek]

[05:55:02 CEST] <Lac3rat3d> Is there an ffmpeg API? If so, what language(s) does it interface with? Is there a basic tutorial?
[08:55:14 CEST] <BtbN> Depends on what you mean by ffmpeg api. There is no api to interface with the ffmpeg cli tool. But the ffmpeg tool just uses the libav* libraries itself.
[09:36:27 CEST] <chungy> he didn't wait around for an answer
[09:43:08 CEST] <chama> can some one help me to calculate color values for colorchannelmixer
[09:43:11 CEST] <chama> ??
[09:43:56 CEST] <chama> I need to implement Willow effect on the following url using ffmpeg
[09:43:58 CEST] <chama> http://designpieces.com/2014/09/instagram-filters-css3-effects/
[09:44:08 CEST] <chama> any idea?
[10:26:29 CEST] Action: _DragonsLordKERN is back (gone 171:45:21)
[10:31:00 CEST] <durandal_1707> chama: look in hex editor values of colors of raw picture
[11:38:07 CEST] <nicki> Anyone know how to solve this error in iOS. "codec not found: h264" . I'm using ffmpeg C API
[13:04:58 CEST] <layosvoncyber> Hi Guys, I'm building a script that zoomout from a picture. The problem is that picture is not in the center of the screen
[13:05:01 CEST] <layosvoncyber> ffmpeg -loop 1 -i test.png -frames:v 300 -vf "zoompan=z='if(lte(zoom,1.0),6.5,max(1.001,zoom-0.05))':d=125:x=-1000:y=-1000" -pix_fmt rgba -vcodec png LOGO.MOV
[13:06:28 CEST] <layosvoncyber> so I'm looking for a solution to minimalise the picture in place
[13:11:06 CEST] <layosvoncyber> this is how it looks now: https://www.dropbox.com/s/r6u7eg77biznynt/LOGO.MOV?dl=0
[13:16:17 CEST] <dexter_> Hey guys, can ffmpeg be acclerated with Intel Haswell under linux?
[14:21:33 CEST] <chama> hi, how to adjust brightness, contrast, etc. with colorchannelmixer?
[15:00:00 CEST] <randomdue> [12:06:26] <layosvoncyber> so I'm looking for a solution to minimalise the picture in place
[15:00:17 CEST] <randomdue> crop the video around the image
[15:00:26 CEST] <randomdue> then process the result with your script
[15:04:17 CEST] <layosvoncyber> <randomdue>, well it is a transparent png basicly
[15:13:37 CEST] <feliwir> hey, not sure if this the right place to ask, but where can i find libvp62? I know ffmpeg used that as a resource for their vp6 decoder, but i can't find it on the web
[15:15:06 CEST] <Hfuy> Hello. I have a lot of files like the one listed by ffmpeg -i here: http://pastebin.com/exDuFu7q
[15:15:17 CEST] <Hfuy> fuy> There are four 24-bit, 48KHz audio channels. The useful audio is inthe second two (VLC plays silence, I suspect it's playing the first two). I'd like to end upwith the same image data, but with the second two tracks as the stereo audio, and at 16-bit. Can ffmpeg do that?
[15:15:53 CEST] <hardikj> hi, I am trying to record my screen using ffmpeg on a window machine with  a very low configuration (1core, 2 GB ram). I want to record some CPU intensive work like browser test and ffmpeg seems to be consuming lot of CPU
[15:16:25 CEST] <hardikj> ffmpeg -rtbufsize 1500M  -framerate 8 -f gdigrab -threads 0  -i desktop -vcodec libx264 -preset ultrafast -g 60 -maxrate 2000k -bufsize 2000k -crf 40 out.mp4
[15:16:35 CEST] <hardikj> ^this the command I am using right now
[15:16:51 CEST] <Hfuy> hardikj: Define "a lot". H.264 is not an easy thing to create.
[15:17:27 CEST] <hardikj> Hfuy, hi, I don't need a very high res vid just a normal video, can you suggest alternative?
[15:17:37 CEST] <Hfuy> mjpeg is less work.
[15:17:40 CEST] <feliwir> hardikj: screen capturing uses a fair amount of cpu, what did you expect?
[15:19:12 CEST] <hardikj> feliwir, I just wanted to know lowest possible cpu I can consume, becausecause right it seems to take 30-35% CPU and with selenium test running everything hangs
[15:19:33 CEST] <hardikj> Hfuy, I will try mjpeg thanks
[15:19:55 CEST] <hardikj> anything else I can change to improve the CPU usage?
[15:20:48 CEST] <feliwir> use your gpu for screen capturing
[15:21:02 CEST] <feliwir> or get yourself a gpu that supports that :)
[15:21:57 CEST] <hardikj> feliwir, hehe, the use case is to record selenium test on 100s of machines
[15:22:04 CEST] <hardikj> I can afford gpu :(
[15:23:07 CEST] <hardikj> Is there any format I can use which consume lowest CPU ?
[15:23:16 CEST] <Hfuy> As feliwir says, screen capturing may never be a very low CPU job.
[15:23:25 CEST] <Hfuy> That said, if you are not sensitive to disk space usage, you can record it uncompressed :)
[15:23:43 CEST] <feliwir> ah. Can someone please answer my question from earlier?
[15:25:48 CEST] <Hfuy> What's the question?
[15:26:24 CEST] <feliwir> i asked, where i can find libvp62
[15:26:46 CEST] <Hfuy> Absolutely no idea.
[15:26:53 CEST] <feliwir> since ffmpeg used that as reference for their vp6 decoder someone might still have a download link
[15:26:59 CEST] <Hfuy> What would the -c:a entry for uncompressed 16-bit 48KHz be
[15:28:01 CEST] <Hfuy> Apparently, "pcm_s16le"
[15:28:38 CEST] <randomdue> i would just leave the audio alone
[15:28:42 CEST] <randomdue> re mux it
[15:29:21 CEST] <Hfuy> This audio is just an on-camera mic. I really only need it as a guide.
[15:29:31 CEST] <Hfuy> I'd like to avoid recompressing the video but it seems to cause problems if I don't.
[15:32:44 CEST] <hardikj> Hfuy,  actually, I wanted to upload the video to s3 in parallel, so that is not an option
[15:33:50 CEST] <Hfuy> s3?
[15:36:54 CEST] <hardikj> amazon web services, S3 storage
[15:37:03 CEST] <Hfuy> Hmm, I see.
[15:37:15 CEST] <Hfuy> Well, you might need a little bit more power, then.
[15:37:57 CEST] <hardikj> Hfuy, just one last time, are sure this is sane
[15:37:58 CEST] <hardikj>  ffmpeg -rtbufsize 1500M  -framerate 8 -f gdigrab -threads 0  -i desktop -vcodec libx264 -preset ultrafast -g 60 -maxrate 2000k -bufsize 2000k -crf 40 out.mp4
[15:38:17 CEST] <hardikj> a low quality video would do to :)
[15:38:18 CEST] <Hfuy> I'm not an expert.
[15:38:21 CEST] <Hfuy> Sorry.
[15:38:48 CEST] <kepstin> that would be really low quality, and if you really want fast encoding it's probably best to drop the vbv controls (-maxrate, -bufsize)
[15:39:03 CEST] <kepstin> although if you're streaming live i guess they make sense
[15:41:01 CEST] <hardikj> kepstin, I am not streaming live, but I have a script that will push some chunks from file say 5mb to S3
[15:41:24 CEST] <hardikj> so I have few more sec after the recording is stopped
[15:44:59 CEST] <guestfwc> hello all i want to use ffmped to convert video from 3gp to webm , what command i use to do this please ?
[15:52:39 CEST] <hardikj> Hfuy, mjpeg to gives me lots of rc buffer underflow
[15:52:45 CEST] <hardikj> any idea?
[16:51:50 CEST] <relaxed> Hfuy: pcm_s16be
[16:52:21 CEST] <relaxed> oh, nevermind, I thought you meant big-endian
[16:53:50 CEST] <relaxed> guestfwc: https://trac.ffmpeg.org/wiki/Encode/VP8
[16:53:53 CEST] <hardikj> relaxed, any idea about my issue? basically reducing cpu usage?
[16:55:03 CEST] <relaxed> try -threads 1
[16:55:22 CEST] <guestfwc> relaxed: ok thank you
[16:56:55 CEST] <relaxed> hardikj: hmm, you have one core
[16:59:32 CEST] <Fyr> guys, if I have a list of files in the directory, how to make them normalize during batch conversion?
[17:01:25 CEST] <hardikj> relaxed, yup :(
[17:02:59 CEST] <codechelvetica> if I tell ffmpeg to extract a frame as a .yuv file from a .yuv video
[17:03:09 CEST] <codechelvetica> will the file have the same pixel format as the video?
[17:03:15 CEST] <codechelvetica> say yuv420p
[17:03:49 CEST] <codechelvetica> I know the video is planar yuv420, and I need a yuv frame representing the single luminance plane and the two chrominance half planes
[17:03:54 CEST] <codechelvetica> etc
[17:05:57 CEST] <klaxa> if you use codec copy, probably
[17:06:27 CEST] <klaxa> like: ffmpeg -i input.yuv -ss 12.345 -c copy -vframes 1 output.yuv
[17:19:02 CEST] <Fyr> guys, where can I find manual on lpc_passes or lpc_method and so on?
[17:43:25 CEST] <Fyr> how to strip off all metadata from file?
[17:43:39 CEST] <Fyr> even wav contains some of it.
[17:47:43 CEST] <feliwir> did anyone found an answer to my question earlier today?
[17:58:08 CEST] <Kolizer> Kappa
[18:56:31 CEST] <feliwir> well i just reask my question: Does someone know where i can get libvp62? I can't find any download link
[18:58:27 CEST] <Fyr> in Linux you can look through repositories
[18:59:21 CEST] <feliwir> as far as i know the library was only available for a short time for download, since On2 did hire some lawyers against it
[18:59:29 CEST] <Fyr> and download source package and compile it in Windows/Linux/MacOS.
[19:00:28 CEST] <feliwir> Fyr: it's not in any repository
[19:01:02 CEST] <Fyr> agreed
[19:01:46 CEST] <feliwir> but since the ffmpeg vp6 codec is based on it i thought someone might still have it
[19:36:03 CEST] <DRAWNBOX> Does anyone know how to reencode a file?
[19:38:02 CEST] <klaxa> can you be more specific?
[19:38:51 CEST] <klaxa> it can be as simple as: ffmpeg -i input.mp4 output.mp4
[19:39:04 CEST] <DRAWNBOX> I have a file and have no clue how its encoded and want to make it h264
[19:39:32 CEST] <DRAWNBOX> I just dont know what I am supposed to put to make it do hs64
[19:39:40 CEST] <DRAWNBOX> h.264*
[19:40:18 CEST] <klaxa> an elaborate guide is here: https://trac.ffmpeg.org/wiki/Encode/H.264
[19:40:43 CEST] <klaxa> you don't really have to worry about the input, if ffmpeg can read it, it will detect it automatically
[19:41:01 CEST] <DRAWNBOX> Thanks, im pretty sure thats what I needed
[19:50:26 CEST] <DRAWNBOX> Do you know the one option so that non ffmpeg players can use it?
[19:50:49 CEST] <DRAWNBOX> klaxa
[19:53:51 CEST] <klaxa> huh? it should be compatible by default
[19:54:10 CEST] <klaxa> are you having problems? you can encode short samples using -t 10 to encode 10 seconds and then check with players
[19:55:26 CEST] <DRAWNBOX> It only works with the video players I downloaded
[19:55:36 CEST] <DRAWNBOX> The video editor I am using doesnt though
[19:55:59 CEST] <klaxa> have you read https://trac.ffmpeg.org/wiki/Encode/H.264#Encodingfordumbplayers ?
[19:56:53 CEST] <DRAWNBOX> Nope
[19:56:57 CEST] <DRAWNBOX> I am gonna try that now
[21:30:23 CEST] <anoop_r> does ffmpeg support qaac ?
[21:45:16 CEST] <Fyr> no
[22:03:21 CEST] <DrBotato> is there a way to restrict ffmpeg to not use all cores? i want to prevent it from slowing down other tasks that might run while it is running.
[22:04:11 CEST] <chungy> -threads 1
[22:04:33 CEST] <DrBotato> excellent! thanks
[22:25:11 CEST] <mbullington> Hello.
[22:25:22 CEST] <mbullington> I'm currently writing an RTSP client in node.js.
[22:26:10 CEST] <mbullington> And I was wondering, if using RTP/AVP/TCP, if I get the RTP packet from that, is there any way to use ffmpeg to parse the RTP packet and encode it?
[22:27:57 CEST] <Fyr> guys, why does volume amplification increase filesize?
[22:58:21 CEST] <iive> Fyr: are you sure this is the only thing you do?
[22:59:00 CEST] <iive> e.g. -c:v copy should copy the video. audio is usually with fixed bitrate, -b:a 128k ...
[23:55:03 CEST] <fortruce> When i capture a window on the screen with gdidraw it only shows a still of the screen with my mouse movements accurately recorded on top of it
[23:55:11 CEST] <fortruce> does anyone have any idea why that might be?
[23:58:52 CEST] <fortruce> it captures correctly for other windows with the exact same command (except for the title)
[00:00:00 CEST] --- Sat Jun 13 2015