[Ffmpeg-devel-irc] ffmpeg.log.20150607

Mon Jun 8 02:05:01 CEST 2015

[00:00:06 CEST] <JEEBsv> you could probably go with one of the fastest presets even
[00:00:16 CEST] <rafael2k> but that could cope encode in realtime
[00:01:10 CEST] <JEEBsv> basically you could cut some of that kind of content and see how well/quickly it compresses with libx264's -q:v 0 -preset veryfast -c:v libx264 or so
[00:01:25 CEST] <rafael2k> I'll do that
[00:01:42 CEST] <JEEBsv> and -pix_fmt yuv422p10 if it tries to do 4:2:0 by default
[00:01:42 CEST] <rafael2k> I bought a Dektec ISDB-T modulator for me to play
[00:01:44 CEST] <rafael2k> ; )
[00:02:31 CEST] <rafael2k> I think I'll convert to 4:2:0 for my tests, less cpu intensive
[00:03:59 CEST] <JEEBsv> do you need it to be intra-only, short gops or you can just leave the default gop length on (or even use the mode where libx264 only puts intra pictures in when that's the best option)
[00:04:20 CEST] <rafael2k> I'd like to have low latency
[00:04:33 CEST] <JEEBsv> that's separate
[00:04:35 CEST] <rafael2k> no temporal compression at all
[00:05:10 CEST] <JEEBsv> short GOPs or intra only mean that clients can connect right away if they didn't have a connection already and thus get all of the packets
[00:05:23 CEST] <JEEBsv> but yeah, if you need intra only then -g 1 or so
[00:05:45 CEST] <JEEBsv> latency is separate
[00:05:52 CEST] <rafael2k> good
[00:06:10 CEST] <JEEBsv> of course I will have to say that you will have to also optimize ffmpeg itself for low latency
[00:06:23 CEST] <JEEBsv> I can tell you to use -tune zerolatency for the least latency options in x264
[00:06:35 CEST] <JEEBsv> but that will not make the rest of ffmpeg possibly optimal for it already
[00:06:38 CEST] <JEEBsv> just keep that in mind
[00:06:48 CEST] <rafael2k> I'll use it, tks! I'm thinking about using less protocols in the networkk stack also, write the data redirect to ethernet frames
[00:07:06 CEST] <JEEBsv> and I just don't remember of all the caching etc. stuff ffmpeg does to the input
[00:07:16 CEST] <JEEBsv> if you want least amount of latency you'll have to minimize that :P
[00:07:37 CEST] <rafael2k> forget, I'll use x264 directlt
[00:07:39 CEST] <JEEBsv> libx264 itself makes it easy (the zerolatency tuning), but you're using it within ffmpeg
[00:07:39 CEST] <rafael2k> directly
[00:07:59 CEST] <JEEBsv> well I don't exactly know how the x264 command line tool does it either
[00:08:21 CEST] <JEEBsv> just don't go about yelling that libx264 can't do low latency since that's been made rather simple with the library ;)
[00:08:32 CEST] <rafael2k> I remember when I worked with DTV, it was pretty small the latency
[00:08:49 CEST] <JEEBsv> yeah, libx264 itself can do really low latency stuff
[00:09:05 CEST] <rafael2k> let me check
[00:09:07 CEST] <JEEBsv> I mean, I have played games nicely with it :D
[00:09:22 CEST] <rafael2k> serious? goooood
[00:09:29 CEST] <JEEBsv> yes
[00:09:36 CEST] <JEEBsv> the library has no issues with latency
[00:10:02 CEST] <JEEBsv> if you have issues with latency when using libx264 in something it is either the rest of the encoding process somewhere else, or on the player side
[00:10:21 CEST] <JEEBsv> which is why I kept saying to you that you would have to optimize whatever you use libx264 in for low latency as well
[00:10:37 CEST] <JEEBsv> libx264 itself does it as soon as you set the zerolatency tuning
[00:13:58 CEST] <DrBotato> dumb question. if i stretch a video from 720p to 1080p with ffmpeg and then play it back at 720p. will it look worse than just playing it at 720p?
[00:14:06 CEST] <DrBotato> without the pre-stretching
[00:17:16 CEST] <atomnuker> DrBotato: nope, not unless you rescale the video 2x original size using nearest neighbour and then scale it down the same way
[00:18:12 CEST] <DrBotato> nope = it will be worse? nope = it won't be worse.
[00:18:19 CEST] <DrBotato> i'm confused by your double negative
[00:19:32 CEST] <atomnuker> 1280x2 != 1920 so nope, it will 'look' worse, detail will be lost
[00:20:31 CEST] <DrBotato> ah ok i see what you mean.
[00:20:40 CEST] <DrBotato> thanks
[07:24:47 CEST] <chama> Hi, is there anyway that i can concat a video with a image
[07:24:59 CEST] <chama> video + (image for 2 seconds)
[17:33:40 CEST] <amoz_> hello. I am newbie. I have gone through ffmpeg.org but got completely lost there. If i want to contribute then, how shall i get started ?
[17:34:28 CEST] <c_14> Fixing bug tickets on trac is always a good start.
[17:36:02 CEST] <amoz_> c_14: thank you for responding. I referred the documentation. but i am still confused. has anyone blogged about it in a simpler way :)
[17:37:13 CEST] <beastd> amoz_: heh. there is lots of blogged information of ffmpeg out there. some is spot on/some outdated/some plain wrong. just use google and you will find lots of hits about ffmpeg.
[17:37:34 CEST] <beastd> amoz_: You have specific reason you want to contribute?
[17:37:59 CEST] <amoz_> beastd: yes. planning for gsoc 2016.
[17:38:32 CEST] <amoz_> actually I am a voluntary contributor to the open source projects of Mozilla community.
[17:38:56 CEST] <beastd> amoz_: also there is an ffmpeg wiki (you can find it easily from ffmpeg homepage)
[17:39:20 CEST] <amoz_> beastd: ohhkk...I will do an exhaustive reading
[17:40:38 CEST] <amoz_> thank you c_14 and beastd
[17:42:14 CEST] <incal> when I concat files with 'ffmpeg -f concat -i $videos -c copy $new' the second part gets a (somewhat) different color tone even tho the original videos look identical in their original files - themselves setup like this: ffmpeg -f concat -i $videos -c copy \
[17:42:14 CEST] <incal>            -c:v libx264 -tune stillimage \
[17:42:14 CEST] <incal>            -c:a aac -strict experimental -b:a 192k \
[17:42:14 CEST] <incal>            -pix_fmt yuv420p -vf scale=1280:720 \
[17:42:17 CEST] <incal>            -shortest $new
[17:44:46 CEST] <beastd> amoz_: Should you want to proceed at some point: Read the homepage. Clone the source code. Try to build ffmpeg current git master on your machine. If that's done, study the documentation and other information sources. Try things you are interested in and try finding the corresponding source code in ffmpeg code base. That is what I would recommend to get familar with the project.
[17:45:43 CEST] <amoz_> beastd: ohhkk....seems a bit lengthy procedure though :P
[17:45:46 CEST] <beastd> amoz_:  reading/subscribing to ffmpeg-user (and maybe other mailing lists) can also help in finding out things
[17:46:08 CEST] <amoz_> yes. definitely.
[19:26:42 CEST] <anoop_r> <anoop_r> hi i got error Past duration 0.904747 too large
[19:26:42 CEST] <anoop_r> <anoop_r> while using x265 to encode
[19:26:42 CEST] <anoop_r> <anoop_r> x265 10bit with ffmpeg
[19:26:50 CEST] <anoop_r>  please see this http://pastebin.com/9L60nhYi
[19:29:31 CEST] <Darby_Crash> hi to all
[19:30:01 CEST] <Darby_Crash> i have a question about ffserver
[19:30:27 CEST] <Darby_Crash> i want re-stream a HLS live channel
[19:31:43 CEST] <Darby_Crash> and i want set ffserver.conf for restream the channel with same codec and quality for video and audio
[19:33:29 CEST] <Darby_Crash> how can i set ffserver.conf?
[19:33:50 CEST] <Darby_Crash> i have read about documentation
[19:34:29 CEST] <Darby_Crash> but i haven't found nothing about this
[19:36:19 CEST] <Darby_Crash> someone can help me?
[19:54:08 CEST] <Darby_Crash> i have solved
[19:54:22 CEST] <Darby_Crash> but i have another question
[19:54:51 CEST] <Darby_Crash> my stream have a problem with buffering
[19:57:24 CEST] <Darby_Crash> http://clbin.com/MyhOe
[19:57:56 CEST] <Darby_Crash> this is my ffserver.conf
[19:58:40 CEST] <Darby_Crash> how can resolve for buffer?
[21:26:43 CEST] <animax> hi all. can I encode a batch of video files in one single process? settings for libx264 shall all be the same for each input file. the files are all contained in the same folder nothing else there in it. afk for a couple minutes ...
[21:27:45 CEST] <c_14> mkdir conv; for video in *; do ffmpeg -i $video [stuff] conv/$video; done
[21:34:48 CEST] <anoop_r> while encoding i get Past duration 0.619041 too large why?
[21:34:58 CEST] <anoop_r> why ffmpeg is messaging like that
[21:35:14 CEST] <anoop_r> if its not a bug then why it logging that
[21:37:23 CEST] <animax> c_14: I'm on windows ... (because of the '$')
[21:37:50 CEST] <c_14> animax: it's still possible. you'll need batch script for it though (or a scripting language)
[21:38:25 CEST] <animax> c_14: really? no command matching my purpose?
[21:39:05 CEST] <animax> never made a batch script ...
[21:39:11 CEST] <c_14> Well, you _could_ built one giant monster of an ffmpeg command. But batch script'll be easier.
[21:39:20 CEST] <animax> where can I find instructions?
[21:42:59 CEST] <animax> ok. so google is your friend ...
[21:47:42 CEST] <Darby_Crash> hi c_14 can you help me?
[21:48:31 CEST] <c_14> With what?
[21:48:54 CEST] <Darby_Crash> i must re-stream a hls stream with ffserver
[21:49:31 CEST] <Darby_Crash> if is possible with same video and audio
[21:49:47 CEST] <Darby_Crash> this is my ffserver.conf
[21:49:49 CEST] <Darby_Crash> http://clbin.com/MyhOe
[21:50:12 CEST] <c_14> Unless you can use codec copy, you'll just have to pick something.
[21:51:12 CEST] <Darby_Crash> i have re encoded it with x256 and liblame
[21:51:53 CEST] <Darby_Crash> because i want more high possible quality
[21:52:09 CEST] <BtbN> you can't enhance the quality, you can only keep it or make it worse
[21:53:22 CEST] <Darby_Crash> with this conf i have a good quality but the stream have buffer problems
[21:54:20 CEST] <BtbN> Not too surprising with x265, propably overloads your cpu
[21:55:17 CEST] <Darby_Crash> on the server the stream don't have problem
[21:55:57 CEST] <Darby_Crash> when i open the stream with a client like vlc on another machine it have many stop and go
[21:57:21 CEST] <c_14> Then the problem is probably network bandwidth.
[21:58:15 CEST] <Darby_Crash> you can say me another way to have the same quality of the source?
[21:58:53 CEST] <Darby_Crash> how can i change my ffserver.conf?
[22:02:16 CEST] <Darby_Crash> i wish a good quality
[22:04:44 CEST] <Darby_Crash> if not the same of the source, a middle
[22:23:16 CEST] <Darby_Crash> ok
[22:23:26 CEST] <Darby_Crash> i have a solution
[22:24:02 CEST] <Darby_Crash> c_14, can you help me a little more?
[22:24:16 CEST] <c_14> With what exactly?
[22:25:36 CEST] <Darby_Crash> https://clbin.com/MNNaT
[22:25:49 CEST] <Darby_Crash> this is my new ffserver.conf
[22:26:59 CEST] <Darby_Crash> i run ffserver
[22:27:22 CEST] <Darby_Crash> after run ffmpeg with the feed in this way
[22:30:03 CEST] <Darby_Crash> livestreamer "hlsvariant://http://manifest.m3u8" best --stdout | ffmpeg -i pipe:0 -vcodec copy -acodec copy -f mpegts -map 0:0 -map 0:1 http://127.0.0.1:8090/live.ffm
[22:30:09 CEST] <Darby_Crash> c_14,
[22:31:55 CEST] <c_14> you'll probably want -override_ffserver
[22:33:45 CEST] <Darby_Crash> https://clbin.com/rPFcm
[22:34:14 CEST] <Darby_Crash> this is the output c_14
[22:37:13 CEST] <c_14> do you get that error when outputting to file?
[22:37:15 CEST] <Darby_Crash> i use livestreamer only to force the stream to best quality
[22:38:47 CEST] <Darby_Crash> c_14, here you can read output https://clbin.com/rPFcm
[22:39:24 CEST] <c_14> change the http://127.0.0.1:8090/live.ffm to out.mpegts and see if you get the same error
[22:40:04 CEST] <Darby_Crash> ok
[22:41:22 CEST] <Darby_Crash> work fine
[22:41:31 CEST] <Darby_Crash> what is the problem?
[22:41:38 CEST] <Darby_Crash> c_14,
[22:44:35 CEST] <c_14> I don't know. The command/config look fine to me.
[22:54:37 CEST] <Darby_Crash> av_interleaved_write_frame(): Broken pipe
[22:56:25 CEST] Last message repeated 1 time(s).
[22:56:25 CEST] <Darby_Crash> frame=    2 fps=0.0 q=-1.0 Lsize=       1kB time=00:00:00.08 bitrate= 105.8kbits/s
[22:56:25 CEST] <Darby_Crash> video:0kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 422.222229%
[22:56:25 CEST] <Darby_Crash> Conversion failed!
[22:56:52 CEST] <Darby_Crash> c_14, here there's the problem
[23:58:42 CEST] <kodur> could anyone help me out on rotating a movie and converting it to webm?
[00:00:00 CEST] --- Mon Jun  8 2015