[Ffmpeg-devel-irc] ffmpeg.log.20131114

[burek]

[00:56] <istvan> hello all - I am trying to learn how to create a simple video player. The tutorial linked by the ffmpeg site ( http://dranger.com/ffmpeg/ffmpeg.html ) is very out of date it seems. When I compile tutorial 8 I get several deprecation errors and other errors. Is there a more up to date example I can download or tutorial I can follow?
[06:03] <ac_slater> Hey guys I want to use ffmpeg to output mpeg1 data via stdout, any clues?
[08:19] <mishehu> greets folks.  I'm getting a little confused by what looks like a circular dependency, and hopefuly somebody can clear it up.  what's the difference between enabling opencv support in the build of ffmpeg versus enabling ffmpeg support in opencv?
[08:20] <tdr> lmishehu build one without.  emerge the other with the support on for the first one.  then rebuild the first one with support for the second
[08:21] <tdr> mishehu, lets the binaries etc provided by them use features of the other
[08:24] <mishehu> ah, so then by building opencv again with support for ffmpeg, a separate opencv program can make calls to ffmpeg functions
[08:25] <mishehu> wanted to make sure this was deliberate and not some legacy stuff that didn't get cleaned up :-)
[08:26] <mishehu> one other quesiton that I'm a little confused on - amd's press release from back in june or july mentions both cv and cl...   but these are not one in the same, correct?
[08:46] <prkhr4u> how to connect ipcamera source to ffserver using rtsp streaming.Camera ip address is :169.254.75.39
[08:49] <l_r> prkhr4u, cannot you get the video stream from the camera and rebounce it to the rtsp server?
[08:54] <prkhr4u> I don't understand....i want to stream live video from my ipcamera and i am using ffserver for that and will play using ffplay
[10:43] <brontosaurusrex> is it possible to define -ss and -t in frames?
[10:46] <zap0> what is a frame?
[10:48] <cbsrobot> brontosaurusrex: no I think only in seconds or timecode
[10:48] <brontosaurusrex> cbsrobot, ok, thanks.
[10:55] <sacarasc> I think -t can be done as frames in -vframes or maybe just -frames.
[10:58] <zap0> why does a stream of data even have any concept of a frame?
[11:14] <brontosaurusrex> because stream of data defines series of pictures zap0 ?
[11:15] <brontosaurusrex> well, i got it working, kinda annoying i have to convert frames to seconds (which brings in framerate for no special reason), but well ...
[11:17] <zap0> nope.   it defines pixels.
[11:18] <brontosaurusrex> zap0, pixels, i want some pixels! go to sleep, must be late in au ...
[11:18] <zap0> you are wrong.
[11:19] <brontosaurusrex> i'am still not gonna have an irc fight, so you are right
[11:19] <zap0> it's not about me.   you have entered the denial stage.
[11:19] <brontosaurusrex> no, you need some sleep.
[11:28] <Samus_Aran> can -force_key_frames be used with -ss/-to and -codec copy so that the resulting clips begin on a keyframe?
[11:29] <Samus_Aran> I'm cutting clips from larger files, but they often have encoder glitches until the first keyframe
[11:31] <zap0> your emphasis on me isn't making you more right.
[11:38] <Theholyduck> Samus_Aran, if you want to do lossless splitting
[11:38] <Theholyduck> Samus_Aran, i suggest using mkvmerge
[11:39] <Theholyduck> its much, MUCH more inteligent about splitting video and audio
[11:39] <Theholyduck> without re-encoding
[11:40] <Theholyduck> http://www.logichaos.com/joomla/guides/35/60-how-to-split-mkv-to-multiple-mkv-files.html Samus_Aran some random guide for how to do it i found by googling
[11:42] <brontosaurusrex> Samus_Aran, i have a script that does fast null x264 encode and use I frame generation to do a sort of a scene detection splicing
[11:42] <brontosaurusrex> but i think ffmpeg has some sort of scene detection filter this days
[11:42] <Theholyduck> brontosaurusrex, why not just use mkvmerge though? it always splits on keyframes,
[11:42] <stonie_> are ffmpeg and avconv totally different encoders?
[11:42] <brontosaurusrex> Theholyduck, sure
[11:42] <Theholyduck> it handles any sort of audio and video ive tried to throw at it
[11:43] <Theholyduck> and, it has all sorts of different splitting modes
[11:43] <Theholyduck> based on filesizes, same lenght files, timecodes, etc,etc
[12:18] <Samus_Aran> Theholyduck: thank you, I will check that app out
[12:18] <Samus_Aran> brontosaurusrex: what do you mean null encode?  and is your script available?
[12:19] <Samus_Aran> how can I check how often keyframes appear in my source file?  I have no idea how precise it can cut if it only cuts on keyframes
[12:22] <brontosaurusrex> Samus_Aran, yes its available
[12:24] <brontosaurusrex> Samus_Aran, in action on osx http://www.youtube.com/watch?v=Vfvq_skLS8Q&feature=youtu.be
[12:24] <brontosaurusrex> and i can post the script if you want
[12:27] <brontosaurusrex> here https://dl.dropboxusercontent.com/u/79532365/ffdrop/sceneDetect3x.7z , same thing 3 times (one is limited to analisis, other is copy, the last is transcode), find a "script" file and adjust it to your os ...
[12:29] <brontosaurusrex> again, it doesn't do the analisis of the stream, it recodes it to null, and use that new data ...
[12:30] <brontosaurusrex> analysis *
[12:33] <brontosaurusrex> + the -ss thingy seems to be mucho improved in latest ffmpegs, so get yourself a really recent git compile.
[14:22] <Xeta> Hi! What is a normal cross platform c++ library to play audio (and or video) with ffmpeg decoding?
[14:23] <JEEB> there's ffmpegsource (ffms2), but that's not really for playback
[14:23] <Xeta> Aha okay
[14:23] <Xeta> Cause ffmpeg/libav can't do the playback, right?
[14:23] <JEEB> no... because ffms2 tries to specialize in frame-exact seeking etc.
[14:24] <JEEB> so it's for cases where you need things like that
[14:24] <JEEB> I think for playback you're better off by just using the C APIs straight up, or using libvlc's C API
[14:24] <JEEB> (which in turn uses the libav* C APIs)
[14:25] <Xeta> I have been using OpenAL but I had some issues. I running on the raspberry pi
[14:25] <Xeta> Oh okay thanks, haven't checked out libav
[14:25] <Xeta> *libVLC
[14:26] <Xeta> So libvlc can do the actual streaming and playback and everything?
[14:27] <JEEB> look at their docs, I just know you can create a playback solution on top of it if you want :P
[14:45] <Samus_Aran> Xeta: isn't there ffplay for that?
[14:45] <Samus_Aran> I just saw it, I've never tried using it for anything.  :)
[14:46] <JEEB> ffplay is nothing else but a simple example player that lets people test some things
[14:57] <Samus_Aran> anyone know if lib-fdk-aac from Franhofer can encode 32bit or 24bit sampled PCM?  I compiled the command line fdk-aac, but it can only encode 16bit
[14:57] <Samus_Aran> I mean, when used in FFMPEG.  I'd have to compile FFMPEG to find out
[14:58] <JEEB> the cli encoder is very limited
[14:58] <JEEB> just use it via ffmpeg or something
[15:00] <Samus_Aran> it doesn't come with either of the static ffmpeg builds available, and I'm on an old distro, it would be a huge pain to compile it with all deps
[15:00] <Samus_Aran> can you confirm it can encode 24 or 32bit PCM?
[15:01] <JEEB> given the whole framework of the ffmpeg cli, yes
[15:01] <JEEB> now just shut up and compile. Also you shouldn't even need many dependencies
[15:01] <JEEB> and yes, binaries with fdk-aac cannot be redistributed
[15:02] <JEEB> because fdk-aac's license says you may only distribute them if you have licensed AAC
[15:04] <Samus_Aran> the license says it's GPL, but they don't protect against patents.  sort of bizarre.
[15:04] <JEEB> no
[15:04] <JEEB> fdk-aac is not GPL
[15:05] <JEEB> https://github.com/mstorsjo/fdk-aac/blob/master/NOTICE
[15:07] <Samus_Aran> I'm referring to the "COPYRIGHT LICENSE; Redistribution and use in source and binary forms, with or without modification, are permitted without payment of copyright license fees"
[15:08] <Samus_Aran> so long a the following conditions are met, which are all compatible with open source
[15:08] <Samus_Aran> but they also specify that they offer no patent protections
[15:09] <JEEB> then you are ignoring the blatant fact that it limits that freedom elsewhere in the license
[15:09] <JEEB> it has also been put through people who know about the licenses more
[15:09] <Samus_Aran> and my mistake on the GPL part, I was thinking about the fact tht it's allowed to change the source and redistribute
[15:09] <JEEB> and it is _NOT_ GPL compatible
[15:10] <Samus_Aran> for many reasons, including that you can't charge license fees if using it
[15:42] <ssspiff> Is there a way I can skip demuxing for an MPEG-TS, and provide the data stream (PES) directly to ffmpeg?
[15:43] <JEEB> you mean to libavcodec?
[15:43] <JEEB> if you can demux the stream, then yes you can just feed it to the decoder
[15:43] <JEEB> (or possibly to ffmpeg if you set input format as raw H.264 or MPEG-2 Video or whatever else you're demuxing)
[15:44] <ssspiff> JEEB: how do I get hold of a decoder context directly, without using a format context?
[15:44] <ssspiff> JEEB: it's in an app using libavcodec, not using ffmpeg
[15:45] <JEEB> just create an AVCodecContext depending on the stuff you've demuxed?
[15:45] <JEEB> and the other related stuff
[15:45] <ssspiff> great, I'll see if I can figure it out, thanks :)
[15:56] <vl4kn0> Hi, is there a way to specify fps using libavformat and libavcodec?
[15:56] <JEEB> yes? set the pts accordingly
[15:56] <Mavrik> vl4kn0, depends on format
[15:57] <Mavrik> setting PTS/DTS is usually synonimous with fps on codecs that do have fixed fps
[15:57] <Mavrik> er, sorry, timebase.
[15:57] <JEEB> if you have a known constant frame rate, just set timebase so that it is 1/25
[15:57] <JEEB> and then +1 the pts every time
[15:57] <JEEB> thus, you get 25fps
[15:57] <vl4kn0> We are talking about decoding, right?
[15:58] <JEEB> either
[15:58] <JEEB> I mean, if you know the frame rate and you want to fix whatever is coming from libavformat
[15:58] <JEEB> feel free
[15:59] <vl4kn0> yes, I want to have 4 frames per second, so I only need to set time_base to 0.25 ?
[15:59] <JEEB> wait
[15:59] <JEEB> what exactly do you mean with "specifying fps"?
[16:00] <JEEB> do you want to convert the frame rate, or just read in the frames so that their frame rate is set to X?
[16:00] <vl4kn0> JEEB: I want to extract 4 video frames per second
[16:00] <JEEB> so you want to convert the frame rate
[16:00] <JEEB> that's a separate issue and you can do that in multiple ways. There's a filter for that as far as I know, for dropping frames
[16:03] <vl4kn0> JEEB: in that case, would it be possible to keep track of frames read and use only every N-th frame ignoring every other frame?
[16:04] <JEEB> every Nth would work if you know you will always have a constant frame rate. Also you'd have to make sure you actually decode and only ignore the decoded pictures after that
[16:04] <JEEB> otherwise formats that use inter prediction will just break
[16:05] <vl4kn0> JEEB: good, that sounds like exactly what I need.
[16:05] <JEEB> there is a filter for that already in libav* methinks
[16:06] <JEEB> if you want you can look into just using that
[16:06] <JEEB> (I think it'd be in libavfilter)
[16:06] <Mavrik> yeah, using the fps filter should be the wisest thing
[16:06] <vl4kn0> JEEB: might as well do that
[16:06] <JEEB> Mavrik, yes -- not reinventing the wheel is generally a good idea :D
[16:07] <Mavrik> yeah, especially since it handles annoying stuff like fixing pts/dts, duplicating, moving and dropping frames :P
[16:07] <JEEB> yup
[16:08] <vl4kn0> Yeah, yeah. I get it, I'm using the filter.
[16:24] <Zeranoe_> Can FFmpeg generate a 15 second sample media file that is maybe something like static or just about anything. I need to run some tests on lots of videos and need some sample clips
[16:25] <ssspiff> Zeranoe_: no but there are a bunch of samples on http://samples.ffmpeg.org
[16:25] <ssspiff> Zeranoe_: don't take my "no" as set in stone, I just don't know of any way, but I'm no expert
[16:26] <Samus_Aran> I wonder if you could encode /dev/urandom as some raw video format
[16:26] <Samus_Aran> would be pretty silly.
[16:26] <ssspiff> Samus_Aran: I was thinking about that, but I'm not sure it would be a good idea :D
[16:26] <vl4kn0> JEEB: is vf_fps the filter I want?
[16:27] <Samus_Aran> ssspiff: better idea: use FFMPEG's image input to generate a video of a single image
[16:27] <Samus_Aran> just set a very long frame duration, like 30 seconds
[16:27] <Samus_Aran> and one frame
[16:28] <Samus_Aran> or set it to a high FPS if that's what you're testing
[16:28] <Samus_Aran> I don't know what you're trying to do.
[17:20] <ac_slater> Hey guys is there a channel for ffmpeg development? (ie - using libavcodec, etc)
[17:36] <saste> ac_slater, yes
[17:37] <ac_slater> saste: duh ffmpeg-devel.
[17:37] <ac_slater> tgabjs
[17:37] <ac_slater> thanks*
[17:37] <saste> ac_slater, ffmpeg-devel if for *internal* ffmpeg development
[17:38] <saste> API users should ask here
[17:38] <ac_slater> oh haha. I'll ask here then, thanks.
[17:39] <ac_slater> Hey guys, before I dig into libavcodec, I have some image data (raw BGR 8bit per channel) and I need to feed this to a RTSP server that can only accept elementary MP4 data (I think that means just the video without headers?). Any advice?
[17:39] <ac_slater> saste: Sorry for the prefix, pasted from my question in the devel channel
[17:53] <ac_slater> or ... I guess this might be more appropriate here. Before I attempt to code this myself, I would love to pipe some v4l2 device via mp4 to ffserver. Googling this is a mess. Any pointers?
[18:13] <Samus_Aran> ac_slater: you said you have image data, and video4linux2.  what are you dealing with?
[18:14] <ac_slater> Samus_Aran: image data from v4l2, ie - frame grabs
[18:15] <Samus_Aran> realtime h.264 encoding?
[18:15] <Samus_Aran> where's it going?
[18:16] <sacarasc> Like everything these days, to Google and the NSA.
[18:18] <ac_slater> Samus_Aran: via RTSP. I've noticed that ffserver can do this. I'd like to try this before coding something myself. But basically, the RTSP server I'm working with NEEDS elementary mp4 video data, I was curious if it's possible to "convert"/"encode" my v4l2 BGR data into MP4(e) data
[18:18] <ac_slater> (lots of confusion on my end(
[18:18] <ac_slater> )
[18:30] <Samus_Aran> sacarasc: that made me laugh, though rather dark.
[18:30] <Samus_Aran> ac_slater: mp4 is a container format, not a video codec.  it can house a few video and audio codecs
[18:31] <Samus_Aran> usually h.264/AVC video and AAC audio
[18:32] <Samus_Aran> ac_slater: this helpful?:  https://trac.ffmpeg.org/wiki/How%20to%20capture%20a%20webcam%20input
[18:33] <Samus_Aran> I've never used v4l2 except to crash my laptop briefly... heh.  it doesn't like my webcam drivers
[18:34] <Samus_Aran> it crashes my USB and takes the wireless with it until next reboot.
[19:06] <ac_slater> Samus_Aran: that is helpful thanks. I guess I need to put the data into non-h264 MPG4... is that even a thing. Containers vs codecs is making my head hurt
[19:25] <ac_slater> Alright maybe someone can help me out, here is my ffserver.conf and the launch string I'm using. How do I connect to the bloody thing? Most rtsp clients are returning 503 http://paste.debian.net/plain/65881
[19:30] <ac_slater> any help is appreciated.
[19:41] <ac_slater> So as a newbie, ffserver is not very user friendly. I assume it works, but I cant get anything out of it.
[19:42] <ac_slater> All I want is v4l2->mp4->rtsp
[20:21] <maujhsn> Mic issue! http://pastebin.com/rm1wKvCV
[20:21] <maujhsn> Would like someones help!
[20:25] <maujhsn> ubitux  Mic issue! http://pastebin.com/rm1wKvCV
[20:29] <maujhsn> Maverick Can you check this out for me: http://pastebin.com/rm1wKvCV
[20:29] <Maverick|MSG> Mavrik ^^
[20:29] <Maverick|MSG> (I think)
[20:30] <maujhsn> Maverick|MSG Can you check this out for me: http://pastebin.com/rm1wKvCV
[20:31] <maujhsn> Mavrik If you have an answer shoot!
[20:33] <sacarasc> maujhsn: First, upgrade!
[20:34] <maujhsn> sacarasc Hi its been a while since we last communicated!
[20:35] <maujhsn> sacarasc Is that really necessary for a command thats not all that complex!
[20:35] <sacarasc> There could be a bug in your nearly 2 year old version.
[20:38] <maujhsn> sacarasc I have not used this version in over a year because i had the liveusb stuck in a draw! How is a bug created out of thin air? Lets reason together!
[20:41] <maujhsn> sacarasc Do bugs arbitrarily occur after a commands success?
[20:42] <sacarasc> Did you use that exact same command on that exact same system successfully?
[20:44] <maujhsn> sacarasc The only difference in this machine is that its a 32 bit rather that 64 bit HP compaq laptop!
[20:44] <sacarasc> Anyway, use lsof to see what is using /dev/dsp and see if you can close it, maybe.
[20:45] <sacarasc> Or, update.
[20:46] <maujhsn> sacarasc  Damn it gave me a laundry list!
[20:53] <llogan> maujhsn: you should not accuse people helping you for free of being "JERK"s.
[20:57] <maujhsn> llogan Now here a penny for that thought!
[20:57] <llogan> the reason i did not answer you is that i was not at my computer. just because a name is listed in this channel does not mean that the user is active, and it does not mean that you're being ignored (on purpose).
[21:01] <maujhsn> llogan Now that you have a FREE moment: http://pastebin.com/rm1wKvCV
[21:02] <maujhsn> du -ah in /dev doesn't show the device busy!
[21:02] <llogan> sorry, i have no experience with oss devices
[21:03] <maujhsn> llogan Shove it!
[21:04] <maujhsn> Llogan its a great place for that penny!
[21:05] <llogan> you're not going to get any help here
[21:05] <maujhsn> Llogan BUT YOU DO NEED HELP!
[21:06] <llogan> just so you know i'll set your name to ignore, so don't waste your time since i'll never see you again
[21:07] <maujhsn> llogan And when your funding does run out some day! Perhaps thhey will give you the axe gladly! :)
[21:08] <aphirst> er, what the shit, maujhsn
[21:08] <maujhsn> er?
[21:08] <maujhsn> lol
[21:08] <maujhsn> shit?
[21:22] <maujhsn> http://pastebin.com/rm1wKvCV....SOLVED!
[21:25] <maujhsn> It's great to know that If I don't ask certain people questions anymore I not have to listen to their GARBAGE!
[21:36] <LithosLaptop> lol
[22:44] <aphirst> oh man, building ffmpeg-git takes forever on my toaster
[00:00] --- Fri Nov 15 2013