[Ffmpeg-devel-irc] ffmpeg.log.20150708

burek burek021 at gmail.com
Thu Jul 9 02:05:01 CEST 2015

[00:56:53 CEST] <causasui> can ffmpeg print the output stream to stdout instead of a file?
[00:57:06 CEST] <c_14> sure
[00:57:09 CEST] <c_14> pipe:1
[00:58:30 CEST] <causasui> c_14: I swear I searched the manpage for "stdout" and didn't see this. thanks :)
[01:10:02 CEST] <techtopia> hey guys
[01:10:19 CEST] <techtopia> can someone tell me what causes these warnings
[01:10:20 CEST] <techtopia> http://i.imgur.com/Q6pKz3G.png
[01:10:29 CEST] <techtopia> and who i can avoid them if possible
[01:13:41 CEST] <debianuser> Hah! Found another way to rotate video 180p : -metadata:s:v rotate=180
[01:14:05 CEST] <techtopia> you can use transpose to do it also
[01:14:38 CEST] <debianuser> Heh, I used -vf vflip:hflip earlier :)
[01:15:37 CEST] <techtopia> ffmpeg -i in.ts -vf "transpose=X" out.mkv
[01:15:41 CEST] <techtopia> where X =
[01:15:50 CEST] <techtopia> 0 = 90CounterCLockwise and Vertical Flip (default)
[01:15:50 CEST] <techtopia> 1 = 90Clockwise
[01:15:50 CEST] <techtopia> 2 = 90CounterClockwise
[01:15:50 CEST] <techtopia> 3 = 90Clockwise and Vertical Flip
[01:16:26 CEST] <pzich> certain players don't read the metadata correctly, so you may be better off with flip/transpose and making sure the metadata is rotate=0
[01:16:27 CEST] <debianuser> Erm... And which one is 180p ?
[01:16:35 CEST] <c_14> You should also be able to rotate=PI
[01:17:24 CEST] <debianuser> techtopia: That warning is a warning to someone who _builds_ ffmpeg binary, not the one who runs it. You can't do anything about it (and even if you'd built it you probably can't do anything either, if you used -vf crop which almost always makes the image unaligned).
[01:18:05 CEST] <techtopia> ahh i thought it was saying audio and video were unaligned
[01:18:12 CEST] <techtopia> yes it is being cropped
[01:18:23 CEST] <techtopia> ok thanks for the info :)
[01:20:42 CEST] <debianuser> c_14: Hah, I've seen rotate= just wasn't sure if it has an optimization for 180p case. I mean I don't want it rotated to 3.14, I want 3.14159265358979323846...
[01:21:53 CEST] <c_14> I have no idea, I just think radians are fun.
[01:22:00 CEST] <debianuser> :)
[01:22:34 CEST] <debianuser> pzich: Good point. Thank you!
[01:59:28 CEST] <well0ne> hi guys
[01:59:41 CEST] <well0ne> i'm using the drawtext filter to display the actual timecode from the file
[01:59:42 CEST] <well0ne> -vf "drawtext=fontfile=tahomabd.ttf: timecode='00\:00\:00\:00': r=23.976: x=(w-tw)/2: y=h-(2*lh): fontcolor=white: box=1: boxcolor=0x00000099"
[01:59:53 CEST] <well0ne> but i dont need the hh and ff field
[02:00:07 CEST] <well0ne> can i tell the filter to ignore thoose fields?
[02:00:58 CEST] <well0ne> the question was asked here too but no results
[02:00:59 CEST] <well0ne> http://superuser.com/questions/839834/is-it-possible-to-modify-the-timecode-format-of-ffmpeg
[02:11:33 CEST] <well0ne> anyone?
[02:13:36 CEST] <pzich> no idea, did you try leaving it off of the timecode='00\:00\:00\:00' ?
[02:42:01 CEST] <well0ne> yes
[02:42:09 CEST] <well0ne> then its says its a wrong syntax
[05:15:02 CEST] <hendry> when i kill ffmpeg during a screencast, my voice is cut off http://s.natalian.org/2015-07-08/cutoff.mp4
[05:15:29 CEST] <hendry> here is the log http://s.natalian.org/2015-07-08/cutoff.txt ... can I do anything to prevent that? just going a normal kill.
[05:17:28 CEST] <hendry> kill -INT $pid # has the same problem
[07:55:13 CEST] <f1resh> Hi all
[07:56:27 CEST] <f1resh> Could someone please help me to configure FFMPEG 2.7.1 (Ubuntu 14.04 x64). It can't find libx264.so, while it is installed properly (i think properly)
[09:33:42 CEST] <durandal_170> f1resh: where is your libx264 pkgconfig located?
[09:57:38 CEST] <f1resh> durandal_170: not sure if i get you... i've built libx264 from latest stable release snapshot
[10:00:07 CEST] <pzich> somewhere on your computer?
[10:02:07 CEST] <f1resh> yes, same PC
[10:02:23 CEST] <f1resh> i've downloaded libx264, built it and installed
[10:02:52 CEST] <f1resh> what is pkgconfig? )
[13:30:49 CEST] <neo1691> A question slightly unrelated to ffmpeg, but I will still go through: Is it possible to have an hls variant playlist with multiple video-only stream and one audio-only stream of the same media?
[13:31:42 CEST] <neo1691> Let's say I have foo.mp4, so I create 4 different encodings of foo.mp4 in various bitrates, without audio. and I create 1 audio encoding of foo.mp4. Does HLS supports this?
[13:54:28 CEST] <ILEoo> yes, but could be that all stock players on mobile devices etc don't support that
[14:29:43 CEST] <kanni> hey folks! anybody here who could help me out with ffmpeg on an older mac?
[14:31:44 CEST] <spaam> only if you tell what your problem is, then maybe someone might can help you with it
[14:32:01 CEST] <spaam> with out knowing the problem, we cant help you with it
[14:33:35 CEST] <kanni> allright. i just figured out that it's not a problem with the mac but with the webcam i'm trying to use [QTKit input device @ 0x7ffec0f025c0] [0] HD Pro Webcam C920
[14:34:34 CEST] <kanni> the process starts but never continues after this: http://llll.io/1JTSgWG
[14:35:03 CEST] <kanni> if i unplug the webcam and use the built in one (same startup parameters) it works just fine
[14:41:50 CEST] <kanni> thats what i'm starting it up with, btw: ffmpeg -f qtkit -video_device_index 0 -i "" out.mpg
[14:44:12 CEST] <zarkone> hello all! is it passible to stream to http with no ffserver? or, how to implement my own ffserver?
[14:51:35 CEST] <zarkone> ... i see in docs that ffserver use ffm2 format, but i can't find the spec
[14:52:51 CEST] <zarkone> or may be i shouldn't use ffmpeg? i want to re-stream RTSP IP-cam video to web page w/ websockets..
[14:53:15 CEST] <zarkone> so, any thoughts appreciated
[14:59:03 CEST] <c_14> zarkone: have a web-server which listens somewhere for put/post and send ffmpeg's output there
[15:00:14 CEST] <zarkone> c_14: thanks for put, just listened for post
[15:00:54 CEST] <zarkone> btw, found node.js solution (server listens for all method by default i guess): https://github.com/phoboslab/jsmpeg/blob/master/stream-server.js
[15:01:07 CEST] <zarkone> so, it is just server =)
[15:15:40 CEST] <[-T-]> hey
[15:16:07 CEST] <[-T-]> is it a know issue that swscale crashes when doing 720x576 to 720x576 pix_fmt convertion ?
[15:28:28 CEST] <neo1691> ILEoo: can you give me a link or something as to how to do that? I made one but it is not working.
[15:29:35 CEST] <ILEoo> neo1691: I think pantos draft has example for that too, most likely player you are using doesn't support it
[16:41:10 CEST] <neo1691> ILEoo: Will you please take a look here? http://pastie.org/private/xkhlqxmlufk3gd4b6wxkq I have uploaded the playlist along with a small description of the videos that I am using
[16:45:59 CEST] <ILEoo> neo1691: sure
[16:47:04 CEST] <neo1691> thanks
[16:49:54 CEST] <ILEoo> neo1691: you're missing group-id etc, take a look https://tools.ietf.org/html/draft-pantos-http-live-streaming-16#section-8.7 as example howto map those video/audio tracks
[16:50:07 CEST] <JEEBsv> thank goodness HLS is now a spec
[16:50:22 CEST] <JEEBsv> the times when it was apple-specific derp was kind of ugh
[16:58:14 CEST] <neo1691> ILEoo: Thanks. I will take a look, I would again like to mention that the video variants do not contain any audio stream, the audio is provided separately
[16:59:45 CEST] <ILEoo> neo1691: yep, that takes it to account, but I'm not sure what players handle that case
[18:15:27 CEST] <nyuszika7h> why is ffmpeg using q=23.0 pretty much everywhere in the file, even with crf=18?  ffmpeg -i in.mkv -map 0 -c copy -c:v libx264 -preset slow -crf 18 -vf subtitles=in.srt ../out.mkv
[18:16:01 CEST] <JEEBsv> that value pretty much is useless :P
[18:16:13 CEST] <nyuszika7h> what is useless?
[18:16:26 CEST] <JEEBsv> the q one that ffmpeg prints
[18:16:30 CEST] <JEEBsv> at least for your use case
[18:17:15 CEST] <DHE> if you really really care, press '+' a few times until it starts printing per-frame stats
[18:17:41 CEST] <JEEBsv> not like the quantizers say too much about the quality of the end result, so you probably don't want it
[18:18:13 CEST] <nyuszika7h> well, the quality seems fine so ok :P
[18:18:16 CEST] <JEEBsv> the libx264 stats are most probably much more useful for you
[18:18:18 CEST] <DHE> and I'd say crf=18 is probably fine on visual quality unless it's some kind of algorithmically generated image
[18:42:20 CEST] <bakkus_> Hello. I have a video file with a big _purple_ filler that I need to crop away. It would appear that crop and crop detection is only geared towards finding black fields and cropping them. Any way of setting what color to look for when detecting?
[18:44:39 CEST] <durandal_170> bakkus: you could replace purple with black
[18:46:07 CEST] <BtbN> Damn, i still haven't found time to work on that filter...
[18:47:47 CEST] <bakkus> durandal_170: ah, interesting thought. any pointers on how to go about doing that?
[18:48:28 CEST] <BtbN> http://ffmpeg.org/ffmpeg-all.html#colorkey
[18:50:04 CEST] <bakkus> thanks a lot - I'll have a look
[19:00:23 CEST] <dystopia_> i just dump a frame
[19:00:38 CEST] <dystopia_> open it in paint and work out how many pixels need croping from each side
[19:00:46 CEST] <dystopia_> and then manually set it in the encoding line
[19:03:40 CEST] <durandal_170> for how many frames?
[19:03:56 CEST] <dystopia_> just 1 frame is needed
[19:04:22 CEST] <dystopia_> open in paint, enable gridlines, and zome max, each square in the gridlines is equivilent to 1 pixel
[19:04:36 CEST] <dystopia_> so it's a very quick and easy way of working out how much needs cropping
[19:06:59 CEST] <durandal_170> what if cropping changes....
[19:07:24 CEST] <dystopia_> it doesent matter
[19:07:35 CEST] <dystopia_> as long as you crop to the widest possible frame
[19:07:49 CEST] <dystopia_> unless your encoding to your own standards or some other ruleset
[20:14:13 CEST] <sybariten> oh hai
[20:14:47 CEST] <sybariten> i am trying to do ffmpeg -strict -2 -i inputfile.rm -b:v 4000k outputfile.mp4
[20:15:00 CEST] <sybariten> and i am getting     The encoder aac is experimental..... add -strict -2 ....
[20:15:25 CEST] <durandal_170> order is important
[20:15:39 CEST] <sybariten> yes but i thought i tried it at the very end too.... ?
[20:16:00 CEST] <durandal_170> Add it after -i
[20:16:16 CEST] <sybariten> haha
[20:16:40 CEST] <sybariten> unrecognized option "2"
[20:16:53 CEST] <sybariten> hmmm
[20:17:19 CEST] <durandal_170> After -i file
[20:19:50 CEST] <sybariten> phew
[20:19:54 CEST] <sybariten> options are voodoo man
[20:19:59 CEST] <sybariten> that did it... thanks!!!
[21:56:47 CEST] <heeen> 1. can I change the DTS without re-encode
[21:57:29 CEST] <heeen> 2. how can I prevent my mostly still video get blurry over time? Stream #0:0: Video: mpeg4 ( [0][0][0] / 0x0020), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], q=2-31, 200 kb/s, 15 fps, 15360 tbn, 15 tbc
[22:15:47 CEST] <dystopia_> you can transcode dts to ac3 quite quickly
[22:31:41 CEST] <Chuckles32> trying to understand the documentation for creating a video from stills.  Using: ffmpeg -framerate 1/5 -i img%03d.png -c:v libx264 -r 30 -pix_fmt yuv420p out.mp4  Can someone explain to me what the -framerate 1/5 means?  I understand this is the input framrate and the -r 30 is the output framerate.  Documentation says each image will ahve druation of 5 seconds (inverse of 1/5 framse per second)
[22:31:41 CEST] <Chuckles32> .  However, when i change this to 1/15, i don't get a 15 seconds for each still?  What am i missing?
[23:12:42 CEST] <dystopia_> try 1/3
[23:12:47 CEST] <dystopia_> to get 15 seconds
[23:14:30 CEST] <djems54> Hi, I've questions about live streaming, is there anyone connected could help me ?
[23:14:54 CEST] <dystopia_> maybe
[23:14:59 CEST] <dystopia_> ask away
[23:18:09 CEST] <djems54> I try to do live streaming with HTML5
[23:18:28 CEST] <OstlerDev> Are you trying to bind to a port?
[23:18:41 CEST] <djems54> it's work perfectly with webm
[23:19:09 CEST] <djems54> but it is not compatible with many platform
[23:19:26 CEST] <djems54> I use ffserver
[23:19:48 CEST] <djems54> my source is a ip cam AXIS (RTSP)
[23:20:13 CEST] <djems54> I have no problem to create a webm stream
[23:20:40 CEST] <djems54> and I know that it is not possible to live streaming with mp4
[23:21:04 CEST] <djems54> what would be the best alternative ?
[23:21:22 CEST] <djems54> without flash ... if possible
[23:21:26 CEST] <OstlerDev> you actually can technically stream with mp4
[23:21:33 CEST] <OstlerDev> not sure with ffmpeg
[23:21:44 CEST] <c_14> With fragmented moov, it should work
[23:21:48 CEST] <OstlerDev> but if you write the file metadata at the start of the file instead of the end its better
[23:21:56 CEST] <c_14> Won't be much support client side though
[23:23:27 CEST] <djems54> My goal is to maximize compatibility with different clients
[23:23:45 CEST] <djems54> and as much as possible natively ...
[23:24:49 CEST] <c_14> webm/hls
[23:25:07 CEST] <djems54> Is it interesting to do live streaming with HTML5 video ? or use a flash drive is anyway simpler?
[23:25:55 CEST] <djems54> I read the information on HLS, but I struggled to find a list of compatible devices ...
[23:26:24 CEST] <OstlerDev> Most devices are from what I know
[23:28:11 CEST] <JEEBsv> android 3.0+ or newer, generally android 4.x or iOS something or another
[23:28:29 CEST] <c_14> And most general media players.
[23:29:05 CEST] <JEEBsv> I think HLS and MPEG-DASH are the two things that you can get stuff done without plugins
[23:29:21 CEST] <JEEBsv> too bad dash.js is rather wonky
[23:29:38 CEST] <djems54>    the HLS is based on the same codecs as mp4?
[23:29:49 CEST] <JEEBsv> mp4 is a container
[23:29:58 CEST] <JEEBsv> but generally yes, you find AVC and AAC in mp4 :P
[23:30:07 CEST] <JEEBsv> and HLS uses AVC and AAC
[23:30:22 CEST] <djems54> AVC ?
[23:30:30 CEST] <djems54> AAC is a codec for Audio, right ?
[23:30:49 CEST] <djems54> AVC = h264 ?
[23:31:19 CEST] <JEEBsv> yes, H.264 is another name for AVC
[23:31:32 CEST] <JEEBsv> just like H.265 is another name for HEVC
[23:31:58 CEST] <djems54> therefore all devices compatible mp4 (AVC / AAC) are compatible HLS?
[23:32:09 CEST] <JEEBsv> no
[23:32:22 CEST] <JEEBsv> they need to support HLS as well
[23:32:29 CEST] <JEEBsv> packaging is a separate issue to formats :P
[23:32:35 CEST] <djems54> Ok
[23:32:55 CEST] <djems54> it is not related to the player?
[23:33:02 CEST] <djems54> HTML5 video in my case
[23:33:25 CEST] <JEEBsv> probably going to work with android 4.x and iOS versions at least
[23:33:53 CEST] <JEEBsv> but not sure how "HTML5 video" that will be, might just be that the OS will open its video player to open that URL
[23:34:08 CEST] <djems54> ok
[23:34:14 CEST] <JEEBsv> I just know it works on those systems for streaming, so that's it
[23:34:36 CEST] <JEEBsv> for HTML5 video on PCs you probably want to package MPEG-DASH unless you like using flash-based HLS players
[23:37:49 CEST] <djems54>    the easiest way is to use a flash player -client side- (jwplayer) with HLS -server side- (ffserver)
[23:38:14 CEST] <JEEBsv> yes, if you want to feed HLS to everything
[23:38:20 CEST] <JEEBsv> then that is the simplest way
[23:38:57 CEST] <djems54> ok
[23:38:59 CEST] <JEEBsv> you could of course also do packaging in both MPEG-DASH and HLS and feed one for the PC users, and the latter for mobile
[23:39:30 CEST] <JEEBsv> but probably less of a mess to just do HLS for everything if you are OK with flash
[23:40:08 CEST] <djems54> last question, there is there a better solution than ffserver + HLS? or simpler to implement server side?
[23:40:22 CEST] <JEEBsv> uhh, what does one need ffserver for with HLS?
[23:40:25 CEST] <djems54>    I heard about Wowza
[23:40:52 CEST] <JEEBsv> I mean, HLS and MPEG-DASH are both basically generally fed through whatever normal nginx or whatever as files
[23:41:13 CEST] <JEEBsv> you just let the encoder (say, ffmpeg) push the content into a directory
[23:41:31 CEST] <JEEBsv> and serve that directory in your httpd
[23:41:41 CEST] <JEEBsv> bam, you've got both of them set up :P
[23:44:23 CEST] <djems54> i'm talking about live and not vod
[23:46:20 CEST] <JEEBsv> yes
[23:46:22 CEST] <JEEBsv> so am I
[23:46:34 CEST] <JEEBsv> both HLS and MPEG-DASH do live by updating a playlist and having files provided
[23:46:41 CEST] <JEEBsv> read up on them, might be a good idea :P
[23:47:44 CEST] <OstlerDev> is there a way to continuiously segment and convert a file as a file gets larger?
[23:48:04 CEST] <OstlerDev> say I have a stream saving to a file, can I segment that file live as it downloads and grows?
[23:49:16 CEST] <djems54>    a video file being written / recording with ffmpeg can be read with a web server like nginx?
[23:49:42 CEST] <djems54> at the same time
[23:51:47 CEST] <djems54> do you have a command example handy ?
[23:52:26 CEST] <c_14> OstlerDev: besides the segment muxer?
[23:53:28 CEST] <OstlerDev> Well I am currently using this command "ffmpeg -i myvideo.mp4  -c:a libmp3lame -ar 48000 -ab 64k  -c:v libx264   -b:v 96k -flags -global_header -map 0 -f segment  -segment_list myvideo.m3u8 -segment_format mpegts str%05d.ts"
[23:53:48 CEST] <OstlerDev> but I am pretty sure it will stop encoding when it reaches the end of the file, even if the file is still growing
[23:53:55 CEST] <OstlerDev> I have not fully tested it yet though
[00:00:00 CEST] --- Thu Jul  9 2015

More information about the Ffmpeg-devel-irc mailing list