[Ffmpeg-devel-irc] ffmpeg.log.20131227

burek burek021 at gmail.com
Sat Dec 28 02:05:01 CET 2013

[02:04] <PowerCC> hi JEEB
[02:05] <PowerCC> i am not using presets no more silly -psy min-max ;)
[02:05] <PowerCC> since when MEncoder is invite only?
[03:36] <Miklos> I'm considering a local transcode cluster based on ffmpeg vs. cloud transcode (amazon or zencoder) - but for this I need some updated numbers of ffmpeg performance on Xeon E3 CPUs - any idea where I can find this?
[03:36] <Miklos> Or do anyone here use Xeon E3s with ffmpeg
[11:48] <newbie|2> hi
[11:48] <newbie|2> excuse me ... is possible to create video from html pages with ffmpeg ?
[11:49] <jnvsor> How exactly do you want the video?
[11:49] <jnvsor> Like a screencast?
[11:50] <jnvsor> Or is there a video on the page you want to download?
[11:54] <newbie|2> I would like to create a video mp4 from html code ...
[11:56] <newbie|2> for example ... create animation with css3 in html code ... and then create an mp4 video ...
[11:56] <ubitux> record your desktop
[11:58] <newbie|2> I would not do it from the desktop ...
[11:59] <newbie|2> sorry ... maybe I'm saying something impossible
[12:00] <ubitux> you have various ways of doing such things, but ffmpeg won't do the html/css parsing & rendering
[12:00] <ubitux> so you can either use your browser and record the window with ffmpeg, or you could use a web engine like webkit and see if it can outputs rgb frames, which you would pipe to ffmpeg for encoding
[12:03] <newbie|2> thank you very much for your answer ...
[12:04] <newbie|2> I try to find something about
[12:27] <DelphiWorld> ffmpeg -i $a -ar 48000 -cutoff 15000 -c:a libfdk_aac -b:a 128k -profile:a aac_he_v2 /mnt/hdd/Videos/$a.m4v
[12:27] <DelphiWorld> is that good?
[12:49] <ayad_> hello, can you help me to encoder .flv to .mp4 thank's
[12:54] <spaam> how about mux it ?
[12:54] <spaam> ffmpeg -i SuperDuperFile.flv -c copy HemligaFilen.mp4
[12:55] <spaam> if you going to use the same codecs in the .flv file in the .mp4 file
[12:56] <ayad_> cool
[12:57] <ayad_> but i have interrupting on encoding set
[12:58] <ayad_> i have this message : Could not write header for output file #0 (incorrect codec parameters ?): Operation not permitted
[13:01] <JEEB> the actual error should come before that
[13:04] <DeadSix27> any idea -> ?"[matroska @ 0000000003e9d0e0] Can't write packet with unknown timestamp"
[13:04] <JEEB> I think that error says it pretty clearly :D
[13:05] <JEEB> you have an AVPacket that has an unknown timestamp, and you're trying to mux it into matroska
[13:05] <DeadSix27> what is a unknown timestamp
[13:05] <DeadSix27> unknown format?
[13:05] <JEEB> timestamp is a timestamp (usually there are two types, DTS and PTS -- decoding and presentation timestamp)
[13:06] <DeadSix27> on toe other hand, which stream would be affected.. the audio or the video stream
[13:06] <DeadSix27> the*
[13:06] <JEEB> basically the time stamp of that AVPacket (no idea which, probably PTS?) is set to the value that means "unknown"
[13:06] <JEEB> well, that error at least doesn't tell you which it is :P
[13:06] <DeadSix27> :|
[13:07] <DelphiWorld> yo JEEB
[13:07] <DeadSix27> its the video stream
[13:07] <DeadSix27> the first
[13:08] <JEEB> DeadSix27, a) check if you're doing anything funky b) if you are, try to strip that out, and if you aren't, try to make a small sample and minimum command that can replicate it and check if the trac issue tracker says anything about it :P
[13:08] <JEEB> you will either get told that your input sucks, or that you're doing something wrong, or that it's a bug in libavformat or libavcodec or whatever
[13:08] <DeadSix27> then i see no reason to even visit the track
[13:10] <JEEB> you ain't going to get either a reply that tells you that you're doing it wrong, or a possible bug fixed if you don't, though :P
[13:10] <DeadSix27> (wasnt supposed to sound so bad)
[13:10] <JEEB> just look at what you're doing and what's failing, and if you're doing anything weird
[13:10] <JEEB> then start minimizing the way you're replicating it
[13:10] <JEEB> both sample and command line wise
[13:13] <DeadSix27> thing is just i have no idea wether the source is fine or not
[13:13] <DeadSix27> since ffmpeg doesnt complain about it in any way, other than when i try to mix it with another aac stream
[13:13] <DeadSix27> into mkfv
[13:13] <DeadSix27> -f
[13:14] <JEEB> well, if you have no idea then you can't really lose anything by poking the trac. In the worst case scenario someone will just hack up a bad workaround for it, which isn't pretty :P
[13:14] <ayad_> if i add strict -2 my enconding is locked on 43 seco
[13:15] <DelphiWorld> Salut ayad_
[13:15] <ayad_> salut
[13:15] <DelphiWorld> ayad_: vous êtes un arab se que je voi, je supose:)
[13:16] <ayad_> oui melange
[13:16] <DeadSix27> btw JEEB: when i dont modify the source and try to mux right away: test.h264: Invalid data found when processing input
[13:16] <DelphiWorld> ayad_: et je ponce pas que c'est du magreb, se nom c'est plus eastern... non ?
[13:17] <DelphiWorld> et pluto la région du "Sham"
[13:17] <ayad_> oui mix avec Afrique central
[13:17] <DelphiWorld> ayad_: oh, tré bien;)
[13:18] <DelphiWorld> ayad_: moi je suis un algériain, êsse que je peux vous aidé?
[13:19] <ayad_> oui  je cherche à encoder pour une chaine communautaire
[13:19] <DelphiWorld> ayad_: je suis la mon ami
[13:19] <ayad_> les images sont en .flv mais je souhaite l'encoder en .mp4 /pour le faire passer dans le tuyau adsltv en france
[13:20] <saste> can ffmpeg act as an RTSP server?
[13:20] <saste> or is ffserver required for that?
[13:20] <saste> DelphiWorld, ^
[13:20] <DelphiWorld> saste: FFServer...
[13:20] <DelphiWorld> saste: but question, why RTSP?
[13:21] <saste> because I see Martin added an RTSP muxer to ffmpeg
[13:21] <saste> DelphiWorld, I don't know, I'm just trying to see what works and what not
[13:21] <DelphiWorld> saste, if i'm correct... i *THINK* -f rtsp is a outbound filter not inbound i (THINK!)
[13:21] <saste> uhmm...
[13:22] <DelphiWorld> ayad_: envoyé moi en privé svp
[13:22] <saste> no there is also an output
[13:22] <saste> it was written in 2010
[13:22] <saste> DelphiWorld, why not to use RTSP?
[13:22] <DelphiWorld> saste: yes, -f rtsp rtsp://user:Pass@blabla... to push to an rtsp server like wowza
[13:23] <ayad_> allo delphi
[13:23] <DelphiWorld> saste: honestly, i prefer hls or http but not rtsp... rtsp is not widely supported but http is everywhere, even in mars
[13:23] <DelphiWorld> ayad_: privé... messagerie privé:P
[13:23] <ayad_> je veux bientot quitter le burau, on peu poursuivre par email?
[13:23] <DelphiWorld> ayad_: oui, mais envoyé moi un message perso a se moman pour que je te le donne, je peux pas l'écrir en plain public:P
[13:24] <saste> DelphiWorld, i still have that problem with HTTP, streams freeze
[13:24] <DelphiWorld> saste: using ffserver?
[13:24] <saste> it is probably due to TCP segmentation issue
[13:24] <saste> DelphiWorld, yes
[13:24] <ayad_> daya078atgmaildotcom
[13:24] <DelphiWorld> saste: Q: are you trying to evaluate & fix or seeking for a solution? so i may help?
[13:25] <saste> DelphiWorld, the same doesn't happen for example with ffmpeg => UDP => udpxy => HTTP
[13:25] <saste> DelphiWorld, if you know some way to set the TCP maximum segment size on linux
[13:25] <DelphiWorld> ayad_: voir
[13:25] <saste> i tried with setsockopt() on the code and it doesn't help
[13:26] <DelphiWorld> saste: but like i asked. you want this as a solution or you're trying ffserver for ffmpeg dev?
[13:26] <ShorTie> mornin guys
[13:27] <DelphiWorld> ShorTie: i'm shortFF not ShortIE:P
[13:27] <DelphiWorld> saste: pm
[13:27] <ShorTie> does configure --disable-doc disable building all the doc's ??
[13:28] <saste> ShorTie, that's what i would expect
[13:29] <ShorTie> ok, thankz, didn't know if i had to do the other doc's too
[13:29] <ShorTie> running out of room, just trying to make it a little smaller
[14:07] <M75> test
[16:06] <smallfoot-> Who are the jerks, ffmpeg or libav guys?
[16:08] <ubitux> that's a really gracious to go in both channel and ask such question
[16:09] <ubitux> do you really expect a meaningful answer?
[16:09] <smallfoot-> yes, i thought it wud be a good idea to ask in both channels to get it unpartial
[16:09] <smallfoot-> yeah
[16:09] <smallfoot-> Why did libav fork ffmpeg?
[16:10] <ubitux> ask them
[16:10] <ubitux> the whole multimedia community is a jerk area, so your question makes no sense
[16:10] <smallfoot-> Was it because they wanted all the credz and run the show, or was it because ffmpeg refused to modernize and accept patches and make awsm?
[16:10] <smallfoot-> oh, didnt know
[16:10] <ubitux> you should look at the technical differencies instead
[16:11] <smallfoot-> Which is technically superior?
[16:11] <ubitux> make your own judgment
[16:13] <smallfoot-> im incompetent and cant make a meaningful comparision
[16:13] <smallfoot-> i can maybe decide which has the coolest name
[16:13] <ubitux> then i'd say you shouldn't listen to anyone telling you who are the good and bad guys
[16:13] <smallfoot-> well someone must know better than me
[16:13] <smallfoot-> i want whoever knows better than me (anyone) to tell me which is best
[16:14] <ubitux> at best, you'll get ffmpeg biased answers here, and libav biased answers on the other channel
[16:14] <ubitux> if you want a seemingly objective opinion, you need to ask a third party
[16:15] <smallfoot-> hmm, i know no such third party
[16:16] <smallfoot-> is Ubuntu ditching ffmpeg? because gstreamer 0.10 was built against ffmpeg, but 1.0 is built against libav
[16:16] <ubitux> https://github.com/mpv-player/mpv/wiki/FFmpeg-versus-Libav
[16:16] <ubitux> here is a third party
[16:17] <smallfoot-> thanks
[16:17] <ubitux> the reason ubuntu is packaging libav and not ffmpeg is because at the moment of the fork the maintainer of the package moved with the libav folks
[16:18] <ubitux> as a result, the ffmpeg package became a libav package, as libav was meant to be a "replacement" for ffmpeg
[16:18] <ubitux> they made the bet that ffmpeg would die after the fork; that didn't happen
[16:19] <ubitux> there is RFP to have ffmpeg back here: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=729203
[16:19] <ubitux> (it's the same maintainer for debian & ubuntu)
[16:19] <smallfoot-> ah, I see
[16:19] <ubitux> afaik, the choice of libav in gst is an historical choice, but feel free to ask them
[16:20] <smallfoot-> but why did the libav guys try to steal ffmpeg from Fabrice Bellard? isnt Fabrice Bellard internationally recognized as a pimp?
[16:20] <ubitux> steal ffmpeg?
[16:20] <smallfoot-> yeah
[16:20] <ubitux> Fabrice hadn't contributed to FFmpeg since a while
[16:20] <smallfoot-> the github link says that before they forked it into libav they tried to steal it but Fabrice Bellard refused to give up the domain name
[16:20] <smallfoot-> oh I see
[16:21] <ubitux> long story short, some developers were angry at the way it was (see the about page on libav.org), and decided to take over; it didn't work, so they forked
[16:22] <smallfoot-> oki
[16:22] <ubitux> Fabrice didn't say a word in the conflict
[16:22] <smallfoot-> hmm i see
[16:22] <ubitux> but the dns was controlled by FFmpeg developers not wanting the fork
[16:22] <smallfoot-> he was probably too busy pimping dope code to be having time to listen to people whine
[16:23] <ubitux> he's not contributing to FFmpeg since years
[16:23] <smallfoot-> hes probably working on some magic stuff
[16:24] <smallfoot-> the guy is a pimp wizard, he wrote ffmpeg, qemu, tcc, and took the world record in Pi calculation with his own algorithm
[16:25] <ubitux> you forgot jslinux
[16:29] <smallfoot-> yeah that
[16:34] <rsaf> hello, i'm using FFMPEG to capture H264 rtsp stream to .mp4 file
[16:34] <rsaf> and i have problem with keyframe
[16:34] <rsaf> video starts gray until ffmpeg receives first keyframe... can you help me with this?
[16:36] <rsaf> my command line: http://pastebin.com/Pu3K7SJ0
[18:15] <eMBee> good evening
[18:15] <jnvsor> evenin
[18:16] Action: eMBee is struggeling with a wierd behavior, when converting a specific file format it does not prompt to overwrite of the target already exists
[18:16] Action: eMBee is trying to convert files from here: http://30c3.ex23.de/fahrplan_d1.html
[18:17] <jnvsor> pastebin input/output?
[18:17] <eMBee> just: ffmpeg -i file.mp4 file.webm
[18:18] <jnvsor> and output?
[18:18] <eMBee> hold on
[18:18] <eMBee> pastong the output will tell you the fileformat, sec...
[18:19] <jnvsor> most likely it's not even trying to transcode the file since you didn't stipulate any codecs
[18:19] <maujhsn> Hello eMBee, v4l2-ctl tool...I want it to be able to read the parameters of a new webcam that I have hooked up! i.e "frame sizes / frame rates your camera supports"! I want to see the results on the command line
[18:20] <eMBee> http://paste.lisp.org/display/140690
[18:21] <eMBee> it is transcoding but it should prompot, or, if i use -n just exit
[18:21] <eMBee> it does that correctly if i use another file format, as input like some mkv i have laying around
[18:22] <jnvsor> are you sure the output file already exists?
[18:22] <eMBee> yes, i ran the same command multiple times
[18:23] <eMBee> and every time the file gets overwritten
[18:23] <jnvsor> try a simpler output filename like out.webm and see what happens
[18:24] <eMBee> interesting, now it's asking...
[18:24] <eMBee> so the output filename is causing problems, hmm
[18:24] <jnvsor> I'd assume you have some token variable in there that's changing between commands
[18:25] <eMBee> in the filename? then i would have multiple output files
[18:25] <eMBee> there is only one and it gets overwritten every time
[18:26] <eMBee> it looks more like there is a bug in the way ffmpeg handles the filename failing to read it correctly for checking
[18:27] <jnvsor> downloading the file to try it myself
[18:27] <eMBee> and i just tested it with other input files but the same long output name, same problem
[18:28] <eMBee> don't need to download anything, just try that filename as a target
[18:28] <eMBee> the input format seems unrelated
[18:28] <jnvsor> well I need an input either way so I might as well download it
[18:29] <eMBee> of course :-)
[18:30] Action: eMBee just figured, being active in this channel, you might already have some videos laying around :-)
[18:33] Action: eMBee was hoping to just run find -name "*.mp4" -exec ffmpeg -n -i \{\} \{\}.webm \; in a loop to convert any new files while those are being mirrored, so that by morning all is mirrored and converted
[18:34] <jnvsor> Might be able to write a bash loop around that that just numbers them
[18:34] <jnvsor> Think it might be the length of the output file name, but it's not aligned to any power of 2
[18:35] <jnvsor> No, it's the escaped colons
[18:35] <jnvsor> don't know why but they're messing it up
[18:36] Action: eMBee nods
[18:36] Action: eMBee just found that too
[18:37] <jnvsor> Ah I see
[18:37] <jnvsor> ffmpeg handles more than just files - it can output to rtmp streams for instance
[18:37] <jnvsor> so when it hits a colon it assumes it's a protocol rather than a file
[18:38] <jnvsor> giving it the file:// protocol doesn't help either - if I were you I'd just strip the colons
[18:39] <eMBee> well, need to find a way to do it. can't strip them from the input as that breaks mirroring
[18:40] <jnvsor> Ah better idea, wait a moment
[18:41] <jnvsor> Nope - quoting it doesn't work either heh - tried stripping them from output before running the command?
[18:41] <jnvsor> Mind you, I'll report this to ffmpeg's trac
[18:42] <jnvsor> but anyway, if it's supposed to be automatic wouldn't overwriting automatically be the way to go?
[18:43] <eMBee> well, the idea is if the target already exists it's already converted, so that file is done
[18:46] <eMBee> the easiest will probably be a small shell script that cleans the output name and then call that from -exec in find
[18:46] <jnvsor> I'd just list the files, stick that in an array, bash loop over it and process the output after parsing the filenames
[18:52] <eMBee> well, the list keeps changing as the mirror is updated, so that's not practical
[18:53] <jnvsor> I mean you make a list when the program runs - check for duplicate file names (minus the extension) and leave them out
[18:53] <eMBee> anyways, i got that small script working, it's just: in=$1; out=${1//:/-}.webm; ffmpeg -n -i $in $out
[18:53] <jnvsor> works too
[18:54] <eMBee> yup, thanks for your help
[18:54] <eMBee> let me know the trac id of that report, i am curious to follow...
[18:54] <jnvsor> https://trac.ffmpeg.org/ticket/3249
[18:58] <eMBee> hmm, if ffmpeg interprets the filename as a protocol, it should fail because that protocol does not exist, or can't be accessed, or it should treat it as a normal filename (which it does) and then behave like file://
[19:00] <esing> Hi, why is copying the audio codec from an mp4 video file not working: ffmpeg -i video.mp4 -codec:a copy -vn copy.mp3  ... I get this error: mp3 @ 0x110d160] Invalid audio stream. Exactly one MP3 audio stream is required.
[19:03] <esing> Maybe because the mp4 file's audio stream is AAC and that doesn't fit in mp3, hence I have to use  ffmpeg video.mp4 -b:a 192K -vn audio.mp3 for mp4
[19:23] <jnvsor> esing: Sounds like your mp4 file has more than one audio track, pick one with -map
[19:41] <jacob___> hi
[19:41] <jacob___> I am a problem in my video that my sound is to low in volumen
[19:41] <jacob___> how can i 'normalize' sound with ffmpeg?
[19:41] <esing> mediainfo of video.mp4: http://sprunge.us/DjVJ   error message: http://pastebin.com/nLWueC7T
[19:47] <esing> Using .aac instead of .mp3 then -codec:a copy works
[19:48] <jnvsor> Yeah cause it's aac audio codec, mp3 containers don't handle that codec
[19:52] <esing> Looks like .mp4/.3gp/.flv always use .aac codec for their audiostreams on youtube. Just .webm uses vorbis (.ogg).
[19:53] <DeadSix27> thats because webm only supports opus and vorbis.
[19:54] <lkiesow> jacob___: http://ffmpeg.org/ffmpeg-filters.html#volume
[19:54] <DeadSix27> esing: http://en.wikipedia.org/wiki/Comparison_of_container_formats
[19:55] <lkiesow> The volume filter may be what you are searching for
[19:55] <esing> Thanks for the link
[19:57] <DeadSix27> for storing id go for mkv.
[19:57] <mark4o> jacob___: first pass use -af ebur128 to check integrated loudness, second pass use -af volume=+3dB or whatever number is needed to bring it to -23dBFS or whatever volume level is desired
[19:58] <mark4o> jacob___: there is a python script in tools/normalize.py that does it but it may need to modified for your use case
[20:33] <jacob___> Id ont get it
[20:33] <jacob___> i have a video with 1 hour of sound and a background pic (static)
[20:33] <jacob___> but it is 700mb, something very wrong here
[20:33] <jacob___>  how can i improve this (mp4 file)
[20:33] <jacob___> audio pcm_16 streame 44khz
[20:34] <jacob___> wait i show output of ffmpeg about this file
[20:35] <jacob___> http://pastebin.com/3DyvcvaX
[20:36] <jacob___> how can i compress this,.., there is basicly no video movement just background image with spoken voice text, not even music
[20:38] <jacob___> I can i see/detect that my video mp4 file is oversampled
[20:39] <jacob___> and decrease bitrate without loosing quality,
[20:44] <lkiesow> jacob___: If it is just a static picture, but you still want to keep it, you could decrease the framerate and maybe also increase the gop value
[20:44] <jacob___> what is gop?
[20:44] <lkiesow> the amount of frames to the next keyframe
[20:45] <jacob___> cool
[20:46] <jacob___> so , imagine i made a mjpeg (motion jpeg) video where every frame is a keyframe, so if i introduce a GOP, i can reduce the size significantly?
[20:46] <jacob___> coolzzz
[20:46] <jacob___> you ahve a commandline for this
[20:46] <jacob___> ?
[20:48] <lkiesow> As there are only keyframes, the gop size is practically alwasy 1 and you cannot modify it. This option only works if you have partial frames in between keyframes
[20:48] <jacob___> lkiesow: ok,.,so how do i make the latter happen
[20:49] <jacob___> how do i go from a situation where every frame is  a keyframe to partial keyframes interleaved with keyframes
[20:49] <lkiesow> If you still want to use mjpeg you can just decrease the framerate.
[20:49] <lkiesow> Use a different video codec
[20:49] <jacob___> nah, mjpeg was for archiving,..,
[20:49] <lkiesow> At the moment, I would go for h264
[20:49] <jacob___> sure,, H264 looks good to me
[20:49] <lkiesow> Use something like:
[20:50] <lkiesow> ffmpeg -i input -c:v libx264 -r 1 -g 60 out.mp4
[20:50] <lkiesow> for the video
[20:51] <jacob___> ok, for now i only copy the audio and deal with that later
[20:51] <lkiesow> -r 1 meas that there is only 1 frame per second
[20:51] <jacob___> ok
[20:51] <lkiesow> -g 60 means that every 60th frame is a keyframe
[20:51] <lkiesow> meaning you will get 1 keyframe per second
[20:51] <jacob___> so i could do something like  -r 60 -g 60
[20:52] <jacob___> that means 60 fms and keyframe every second?
[20:52] <jacob___> cool
[20:52] <jacob___> 60 fps and 1 keyframe ps
[20:52] <lkiesow> yes
[20:52] <jacob___> cool
[20:52] <jacob___> i try this))
[20:52] <jacob___> moment
[20:53] <lkiesow> But why do you want 60 frames a second?
[20:53] <jacob___> oh ah 50?
[20:53] <jacob___> whats they human eye, can only do 60 fps?
[20:54] <jacob___> i forgot, i had a tv once (non flatscreen) , it had 100 fps
[20:54] <jacob___> crips picture
[20:54] <lkiesow> normal movies have about 25-30 fps
[20:54] <lkiesow> The Hobbit has a revolutionary amount of 48fps :)
[20:55] <jacob___> why did i double it?  mmm maybe my brain is still on interlaced
[20:55] <jacob___> haha
[20:55] <jacob___> Hobbit? lol,.., i thought starwars was the cats wiskers
[20:55] <jacob___> with all the fancy explosions and quick action
[20:56] <lkiesow> :)
[20:56] <lkiesow> But didn't you say that you do have a still image as video?
[20:56] <lkiesow> Then why use a high frame rate?
[20:57] <jacob___> lkiesow:  yeah
[20:57] <jacob___> i was thinking about other vid,
[20:57] <jacob___> you right, sorry for confusion not providing context,..,
[20:57] <lkiesow> In theory you could use one frame that last for the whole movie. Though a lot of players do not like that and fail if you try to seek
[20:57] <lkiesow> ah, ok ^^
[20:58] <jacob___> yes, the seek is a problem,.., if they want to fast forward they end up with crap
[20:58] <LithosLaptop2> any movie going past 24fps looks very cheesy to me
[20:58] <jacob___> so 1 frame per second is good idea
[20:58] <jacob___> http://pastebin.com/6Y9cbCkV
[20:58] <jacob___> i ran a volume detect on my audio
[20:58] <jacob___> ^^
[20:58] <jacob___> ok,.., i will try your command line now
[21:44] <jacob___> lkiesow: fucking hell, the size dropped from 800 mb to 127 mb
[21:45] <jacob___> thanks alot man
[21:45] <jacob___> I have a lot of lecture videos that are way to "fat".., just a guy talking with near static background,.., nice trick you have..
[21:48] <jacob___> lkiesow: i want to use your filter loudness
[21:48] <lkiesow> jacob___: May I ask what lecture videos you have? I'm curious because I'm an Opencast Matterhorn developer which is a lecture recording system :)
[21:49] <jacob___> standford, coursera,.., some german universities, when i download them,.., they are way to freakin big for just talking in front of a blackboard
[21:50] <lkiesow> Ah ok, though maybe you produce them youself& which German universities? ^^
[21:50] <jacob___> these professors are just recording stuff ad-hoc (classroom etc) I think they dont have your experties yet
[21:51] <jacob___> Buch university, (Cryptography course, 22 vids)
[21:51] <jacob___> MOOC is in its infancy
[21:54] <lkiesow> We do that, too. They are being recoded automatically. They don't have to do anything. Everything else does not work execpt for very few lecturers who are in that topic. And you would have to spend a lot of time and money. This semester we produce exectly one pure MOOC. Everything else is lecture recording. But the good point is that a lot of universities start producing right now
[21:55] <JEEB> we've had mooc at cs.helsinki.fi now for two or so years :) And we got a program where some of the people who did two specific courses through the MOOC can get in officially
[21:56] <JEEB> so yeah, many places are starting to provide MOOC education :)
[21:56] <jacob___> MOOC is cool, they should apply the itunes /appstore business model, $1.99 for a course,., but they can sell to millions of people
[21:57] <jacob___> everybody can go to Harv/Stanford..., .. labwork is going to be problem, but with todays cheapmaterials a lab is not that hard compared to a years tution pay
[21:57] <jacob___> tuition*
[21:59] <lkiesow> The thing is that especially the US universities use the MOOCs as advertising material. They don't get much out of it, but their reputation increases. So people want to study there and pay for that
[21:59] <jacob___> lkiesow: about the audo,.., what is the meaning of mprobe.exe what is that?
[21:59] <jacob___> Standford had 2 courses MOOC credited by ACE
[22:00] <jacob___> of course , i would feel cheated if someone could do same course online as i was paying 25k for brick and morter uni)
[22:00] <jacob___> so i think big unis will go slow, but due to compitition we will see big shifts in future
[22:03] <lkiesow> Well, most no-MOOC-recodings are for their students only and you will not get access to them if you are not a student at a specific university. We have 1 or 2 open courses a semester, but really record ~25 (Actually, I don't really know. I don't have to deal with that :)
[22:04] <lkiesow> Mancester for example recods nearly every single couse
[22:04] <lkiesow> They have about 60.000 recordings per semester :)
[22:04] <lkiesow> And everything is processed by FFmpeg :D
[22:05] <theholyduck> speaking of recorded classes
[22:05] <theholyduck> https://sites.google.com/site/northwesternlightboard/home
[22:05] <lkiesow> jacob___: Where did you get the mprobe.exe from?
[22:05] <theholyduck> this guy has the best technique ive seen
[22:05] <jacob___> http://lists.ffmpeg.org/pipermail/ffmpeg-devel/2013-March/141071.html
[22:05] <theholyduck> i love his live, 1 shot, no post processing
[22:05] <theholyduck> all physical effects
[22:05] <theholyduck> approach to recording it
[22:09] <jacob___> fucking heel,.., aweosme
[22:10] <jacob___> theholyduck: awesome^2
[22:10] <jacob___> and its open source hardware too))
[22:10] <jacob___> great guy
[22:10] <theholyduck> jacob___, well, he is a mechanical/electrical engineer
[22:10] <lkiesow> There is no mprobe in that mail
[22:10] <theholyduck> not a software one
[22:10] <theholyduck> jacob___, and so he found a way to do everything physically
[22:10] <theholyduck> and in one shot :P
[22:10] <theholyduck> jacob___, the results are pretty stunning aswell
[22:10] <jacob___> ffprobe
[22:10] <jacob___> oops
[22:12] <jacob___> dont know how is does correct for mirror image while facing the camera
[22:12] <jacob___> doesnt make sense,
[22:12] <jacob___> i bookmarked his page, thanks for the tip, theholyduck
[22:13] <theholyduck> jacob___, if you read the rest of the pages
[22:13] <theholyduck> you see he uses a mirror
[22:13] <theholyduck> and records through it
[22:14] <theholyduck> + uses a polarizer filter to hide the monitor he uses to see what he is doing in
[22:14] <theholyduck> its all very wellw ritten up
[22:15] <jacob___> what i mean is,.., sure you can make it look good for viewer
[22:15] <jacob___> but think about it
[22:15] <jacob___> if his had is writing in upper left corner,
[22:15] <jacob___> hand*
[22:16] <lkiesow> ah, ok. That was also the first thing I thought of: You have to write mirrored. But if it is for video only, I think it is a great ide
[22:16] <lkiesow> Might as well try it out :)
[22:16] <jacob___> if he flips mirror so we see it ok,.., but the letters start in upper right corner
[22:16] <theholyduck> lkiesow, he writes the right way around
[22:16] <theholyduck> but FILMS in the mirror
[22:16] <theholyduck> so
[22:16] <theholyduck> it comes out looking normal
[22:16] <jacob___> oh wait
[22:16] <theholyduck> cause the mirror flips it back
[22:16] <jacob___> you dont see him writing only the text?
[22:16] <jacob___> i mean you dont see they guy himself
[22:16] <theholyduck> jacob___, you do
[22:17] <theholyduck> look at the video
[22:17] <theholyduck> on the first page
[22:17] <theholyduck> i have to go now
[22:17] <jacob___> doesnt make sense, you cant mirror his arm,
[22:17] <jacob___> position, sure you can mirror the fluecense text but not NOT mirror his arm
[22:17] <jacob___> at the same time
[22:18] <lkiesow> I guess it does not matter if he is mirrored in the recording, does it?
[22:18] <lkiesow> What was your problem with ffprobe
[22:18] <jacob___> it would look weird
[22:18] <jacob___> you see his arm left but letters appear right
[22:18] <jacob___> lol
[22:19] <jacob___> i dont see loudness filter used in ffprobe
[22:20] <jacob___> i see something like this "ebur128=metadata=1"
[22:20] <lkiesow> No, ffprobe is just for media analysis. You can use it to get the mean loudness of your audio. Then you can adjust it to a specific value
[22:20] <lkiesow> using ffmpeg in the next step
[22:20] <jacob___> how do i do that?
[22:20] <jacob___> do you have example without all the fuzzyness in the script?
[22:21] <lkiesow> If you just want to make it louder, you don't need ffprobe at all. Do you want that?
[22:23] <jacob___> yeah, but how much louder, would i run the risk of over amplyfying?
[22:23] <jacob___> and some parts of the video have loadness x and other parts loudness y (my ears detected it) , how do i normalize at one level
[22:26] <lkiesow> Ah, ok. The volume filter will just increase/decrease the volume of the whole audio stream.
[22:27] <lkiesow> I guess for what you want to do, you could try the compand filter: http://ffmpeg.org/ffmpeg-filters.html#compand
[22:27] <lkiesow> Maybe even together with the volume filter.
[22:28] <lkiesow> Hm, just  looking at the first example
[22:28] <lkiesow> That could help. But I'm just guessing
[22:28] <jacob___> ok,, ia m looking aswell,.., not making much sense to me.., not media wizz, sorry
[22:29] <lkiesow> Well, just try it out :)
[22:31] <lkiesow> ffmpeg -i input -filter:a 'compand=.3 .3:1 1:-90/-60 -60/-40 -40/-30 -20/-20:6:0:-90:0.2' out.mp4
[22:31] <lkiesow> Or something like that
[22:32] <jacob___> ok
[22:32] <jacob___> i try
[22:34] <jacob___> Unrecognized option '60/-40'. Error splitting the argument list: Option not found
[22:34] <jacob___> ^^ lkiesow
[22:34] <jacob___> something is wrong?
[22:35] <lkiesow> Try using " instead of '
[22:35] <jacob___> i did, already
[22:35] <jacob___> tanks
[22:36] <lkiesow> Did that work?
[22:36] <jacob___> its running now,,,,see what happens
[22:37] <lkiesow> If the volume is to low in general afterwards you could try to prepend the volume filter:
[22:38] <lkiesow> ffmpeg -i input -filter:a "volume=volume=1dB,compand=.3 .3:1 1:-90/-60 -60/-40 -40/-30 -20/-20:6:0:-90:0.2" out.mp4
[22:38] <lkiesow> And adjust the 1dB
[22:38] <jacob___> volume=volume=1dB
[22:38] <jacob___> ok
[22:44] <jacob___> can ffmpeg be GPU accelerated?
[22:44] <jacob___> my cpu is maxed out 100%
[22:59] <jacob___> lkiesow: sounds good
[22:59] <jacob___> i will try the option volume=1db, see what makes diff
[23:30] <jacob___> lkiesow: i got NO SOUND on the last run,..,
[23:30] <jacob___> no volume
[23:36] <lkiesow> hm& just had a look at the normalize script: http://git.videolan.org/?p=ffmpeg.git;a=blob;f=tools/normalize.py;h=e0159133a693fd446ce66a8cc27bbdf00798fb3d;hb=HEAD
[23:36] <lkiesow> Seems like they use ... -filter:a "volume=1dB,...
[23:37] <lkiesow> So maybe there is an error in the docs
[23:39] <lkiesow> No its not& it does not matter how you write it. Could you try
[23:40] <lkiesow> ffmpeg -i input -filter:a "volume=+5dB,compand=.3 .3:1 1:-90/-60 -60/-40 -40/-30 -20/-20:6:0:-90:0.2" out.mp4
[00:00] --- Sat Dec 28 2013

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