[Ffmpeg-devel-irc] ffmpeg.log.20130509

[burek]

[00:03] <denysonique> whats is the ffmpeg screencast guide link?
[00:03] <denysonique> popular on this channel
[00:17] <llogan> denysonique: http://ubuntuforums.org/showthread.php?p=8746719#post8746719
[00:17] <llogan> or https://ffmpeg.org/trac/ffmpeg/wiki/How%20to%20grab%20the%20desktop%20%28screen%29%20with%20FFmpeg
[02:43] <highgod> Hi, all. I want to ask two questions, I have use ffmeg dshow to capture the desktop. First is, does ffmpeg has comand line to use dshow to capture a specific window? The second is, dose it can capture a specific area of desktop? Thanks
[03:29] <BtbN> dshow is directshow, it doesn't have screen recording capabilitys.
[03:32] <sacarasc> You can use it in ffmpeg to do just that.
[03:36] <highgod> just capture the desktop?
[03:47] <highgod> I think I can add a filter like crop to implement it
[05:58] <sacredchao> Can ffmpeg/avconv decode mbaff encoded h.264 streams?
[09:18] <Threefifty> Hello, I am not to savvy with linux but I do have a ReadyNas Pro 6 that I am logged in through ssh. A Thirdparty app called headphones can use ffmpeg to convert flac files into 320kbps mp3's. All it needs is the directory where ffmpeg is installed. I know i have it installed because in ssh i can type ffmpeg and the options for ffmpeg will show. As I stated before I dont know much about linux and if anyone can help me find a way to
[09:18] <Threefifty> would be greatly appreciated
[09:22] <relaxed> Threefifty: run `which ffmpeg`
[09:23] <Threefifty> -bash run command not found
[09:24] <relaxed> type this -->  which ffmpeg
[09:24] <Threefifty> awesome
[09:24] <Threefifty> thank you so much
[09:26] <relaxed> Threefifty: you're welcome
[17:49] <schtinky> I'm attempting to grab iframes from an mpegts digital TV stream with "-vsync vfr -vf 'select(pict_type\,I)'"... what build config options should I have enabled to make this possible
[17:49] <schtinky> when I execute it on a machine with an ffmpeg yum package installed (and all of its config options), the command works fine
[17:50] <schtinky> when I execute it on a machine with an ffmpeg build with "./configure" and no options, the command produces just a few frames and basically fails
[17:50] <schtinky> no real error message though
[17:53] <tclarke> I'm trying to setup ffserver to broadcast an rtp stream of an .mp4 and to loop it continuously (I'm trying to simulate a live camera feed). I'm not sure how to loop the file and I'm having trouble getting the rtp working at all...vlc just errors out...unable to connect to the feed...looks like it might be getting the rtp url from the rtsp address but the url is pointing to port 0
[17:53] <tclarke> any suggestions would be helpfull
[18:09] <Emmanuel_Chanel> Hello! Is https://ffmpeg.org/trac/ffmpeg/wiki/UbuntuCompilationGuide still useful also for Ubuntu 13.04?
[18:14] <dextro_> https://gist.github.com/anonymous/0e30d615fbd363471caf
[18:14] <dextro_> The encoder 'aac' is experimental but experimental codecs are not enabled, add '-strict -2' if you want to use it.
[18:14] <dextro_> i used ffmpeg -i Django.Unchained.2012.DVDSCR.XVID-NYDIC.mdi.flv Django.Unchained.2012.DVDSCR.XVID-NYDIC.mp4 -strict -2
[18:14] <dextro_> :/
[18:22] <dextro_> nvm
[18:22] <dextro_> man pages ftw
[18:39] <paradoxical> Hey, are there any examples of how to do the equivalent of a filter_complex using the avfilter API directly? I'm basically using the code from here: http://ffmpeg.org/doxygen/trunk/doc_2examples_2filtering_video_8c-example.html#a26 but trying to change the filter_descr string to do some more complex filtering.  If I change it to something like "[in]scale=474:316[a];[a]pad=1050:632:25:0[out]" it succeeds.  But then if I try to do somet
[18:39] <paradoxical> hing like "[in]scale=474:316[a];[in]scale=474:316[b];[a]pad=1050:632:25:0[c];[c][b]overlay=551:0[out]" the call to avfilter_graph_config errors out with a -22.
[18:40] <paradoxical> The only examples of using avfilter API seem to not cover how to do anything more complex than just doing scaling, or doing a crop, but nothing for wanting to do overlays or anything more complex.
[18:41] <schtinky> Hey guys, I'm trying to grab an iframe every second from a USB digital tuner card... and do it on a raspberry pi
[18:42] <schtinky> the command I've been using (which works great on my quad-core laptop, using very little cpu) is:
[18:43] <schtinky> ffmpeg -i input.mpg -vsync vfr -vf "select=eq(pict_type\,I)" -r 1 outputfiles%9d.jpg
[18:44] <schtinky> unfortunately, even when overclocked, the raspberry pi takes 1m46s to process 30 seconds of recorded video
[18:44] <durandal11707> that does not take picture every second, but every keyframe
[18:45] <schtinky> -r 1 forces 1 per second
[18:45] <durandal11707> what video codec in in that mpg?
[18:45] <durandal11707> schtinky: -r 1 sets output frame rate
[18:45] <schtinky> ffmpeg says mpeg2video
[18:45] <schtinky> it's a digital mpegts stream from a digital tuner card
[18:46] <durandal11707> if you really need to grab key frames only there is very fast way for some codec(s)
[18:46] <durandal11707> ffmpeg -skip_frame nokey
[18:46] <durandal11707> use above and remove filter code -vf ... and try it
[18:47] <schtinky> keep vsync?
[18:47] <durandal11707> yes
[18:47] <durandal11707> but set vsync -vfr to output, after -r 1
[18:48] <schtinky> "Codec AVOption skip_frame (skip decoding for the selected frames) specified for outputfile #0 (outputfile%9d.jpg) is not an encoding option
[18:49] <durandal11707> skip_frame option goes after -i input.mpg
[18:49] <durandal11707> its for decoding not encoding...
[18:49] <schtinky> same error
[18:50] <durandal11707> ah, before -i ...
[18:51] <schtinky> what do you mena "set vsync vfr to output"?
[18:52] <durandal11707> that you apply it for output part, so set it after "-r 1"
[18:53] <schtinky> dude I think that worked
[18:54] <schtinky> 20 seconds to process 30 seconds of video
[18:54] <schtinky> here's what i used: tell me if you think it's optimal
[18:54] <schtinky> ffmpeg -skip_frame nokey -i inputfile.mpg -r 1 -vsync vfr "outputfile%9d.jpg"
[18:56] <schtinky> and let me see if I understand that command in plain english:
[18:57] <durandal11707> try if -vsync 0 is faster?
[18:57] <schtinky> "video encoding failed"
[18:57] <schtinky> is the -r in the right place?
[18:59] <durandal11707> sorry...
[19:00] <schtinky> unfortunately, that's going to be tough
[19:01] <schtinky> I need to reboot the raspberry into graphical mode
[19:01] <schtinky> what is it you need to see?
[19:05] <durandal11707> error you get
[19:06] <schtinky> http://pastebin.mozilla.org/2388131
[19:07] <schtinky> two commands there, FYI
[19:07] <schtinky> first one works with vfr, second one gets the error with -vsync 0
[19:08] <schtinky> btw, is there an image output format that might take less encoding power?
[19:08] <schtinky> or is jpeg pretty good on the cpu?
[19:09] <durandal11707> you could try: png, tiff, pam
[19:09] <durandal11707> but they usually take more space are they are lossless
[19:17] <schtinky> png took much longer
[19:18] <schtinky> I think jpeg is the best because mpeg and jpeg both use yuv420p
[19:18] <schtinky> png requires a conversion to rgp
[19:18] <schtinky> rgb
[19:18] <durandal11707> you could use rawvideo, no encoding at all, but no compression too
[19:19] <schtinky> ding ding ding
[19:19] <schtinky> tiff is the winner
[19:19] <schtinky> 17s on 30s of video
[19:19] <schtinky> beats jpg by 5 seconds
[19:20] <durandal11707> but it writes yuvs, which are not support by lavc yet...
[19:20] <durandal11707> but if you use libtiff for tiff decoding it will work
[19:20] <schtinky> what's lavc?
[19:21] <durandal11707> libavcodec, ffmpeg uses that library to encode/decode
[19:21] <schtinky> well in any case, I think I'm set
[19:21] <schtinky> thanks a ton for your help
[19:43] <dextro_> schtinky use alix
[19:43] <dextro_> rpi is for chumps
[19:52] <dextro_> frame=185843 fps= 32 q=29.0 size=  419733kB time=01:43:20.91 bitrate= 554.5kbits/s dup=1 drop=0
[19:52] <dextro_> is that pretty slow?
[19:53] <llogan> depends on your input, your encoder and its settings, and your cpu.
[19:53] <llogan> and how you compiled ffmpeg
[19:54] <llogan> among other things im probably forgetting
[19:56] <TheSchaf> io speed :p
[20:02] <llogan> moon phase and planet alignment
[22:10] <dextro_> does ffmpeg lock the files
[22:19] <durandal11707> nope
[23:23] <hendry> can i make a audio mp3 stream using ffmpeg without shoutcast?
[00:00] --- Fri May 10 2013