[Ffmpeg-devel-irc] ffmpeg.log.20130908

burek burek021 at gmail.com
Mon Sep 9 02:05:01 CEST 2013


[00:10] <dampjam> In ffplay I'm trying to apply a video filter on an ftp source, so I have -vf "movie=rtp://0.0.0.0:2000" but I'm getting "Error initializing filter 'movie' with args 'ftp://0.0.0.0:2000'&& any ideas?
[00:11] <durandal_1707> afaik movie filter supports only file protocol (some silly bug)
[00:12] <ubitux> try to escape the :
[00:12] <dampjam> how tough would that big to fix --- I'm trying to merge two rtp streams&. know any other filter I can pass the second ftp stream through?
[00:12] <ubitux> the two : actually
[00:13] <durandal_1707> you do not need to use movie filter anyway...
[00:13] <dampjam> yeah, I'm rescaling them also in real time
[00:14] <ubitux> "movie=rtp\\://...\\:2000"
[00:14] <dampjam> ubitux: nope
[00:15] <durandal_1707> use -lavfi or -filter_complex
[00:16] <ubitux> "ffplay"
[00:17] <ubitux> ffplay ftp://... -vf ...
[00:17] <ubitux> ffplay -f lavfi "movie=ftp\\://,.."
[00:18] <ubitux> gtg, hf&gl
[00:18] <dampjam> http://pastie.org/private/ad4z6nlaxyntcigioaxfaq
[00:18] <dampjam> quick look?
[00:20] <ubitux> "Please don't paste your script"
[00:20] <ubitux> also missing output
[00:20] <ubitux> gtg for real
[00:21] Action: ubitux &
[00:23] <dampjam> Here is one posted with the output: http://pastie.org/private/un0dy8aw8hhtbtbomhudq
[00:31] <CoJaBo> cool.. my laptop can transcode MPEG2 to x264 in realtime
[00:32] <sacarasc> Depending on encoding settings, I would say a lot of things can. :D
[00:33] <CoJaBo> now if only I could find a way to change the channel remotely lol..
[00:44] <CoJaBo> http://i.imgur.com/1u425zi.jpg
[01:55] <moonmayor> hey, I'm trying to create images for each scene change
[01:56] <moonmayor> I've seen an example where ffmpeg will use 'tile' to produce one large image with thumbnails of each scene change
[01:56] <moonmayor> but I'm not sure how to get it to produce each image as its own file
[01:56] <moonmayor> here is the script I'm using right now.
[01:56] <moonmayor> http://pastebin.com/epbKN97L
[02:18] <durandal_1707> moonmayor: there is scene detect in select filter, consult documentation
[02:18] <moonmayor> right, I'm using the scene detect right now.
[02:19] <moonmayor> I'm using -vf select='gt(scene\,0.2), tile=10x150
[02:19] <moonmayor> but tile produces one file with many thumbnails in it.
[02:19] <durandal_1707> than do not use tile...
[02:21] <moonmayor> ok. let me try that.
[02:21] <moonmayor> I'm not sue what that will output.
[02:25] <moonmayor> when I remove tile it generates the image files how I want, but there are tons of duplicates.
[02:28] <moonmayor> looks like the decimate filter may help with deduplication.
[02:32] <moonmayor> oh! that's perfect!
[02:41] <durandal_1707> its because of timestamps and cfr
[02:42] <durandal_1707> using decimate filter for that is waste of cpu cycles
[02:45] <moonmayor> can you think of a better way to dedupe?
[02:48] <durandal_1707> moonmayor: learn about timestamps
[02:49] <durandal_1707> you can also use setpts filter and '-vsync vfr'
[02:49] <moonmayor> ok, cool. I was looking at the -vsync flag.
[02:50] <moonmayor> "Frames are passed through with their timestamp or dropped so as to prevent 2 frames from having the same timestamp." sounds very promising.
[02:54] <durandal_1707> in your case frames have big gaps between timestamps and to keep same fps frames will be duplicated to match cfr
[02:55] <durandal_1707> i think there are also examples on wiki
[02:58] <moonmayor> yeah, that makes sense.
[02:58] <moonmayor> I'm guessing "vfr" is "variable frame rate?"
[02:59] <durandal_1707> yes
[03:00] <moonmayor> makes sense!
[03:00] <moonmayor> thank you!
[05:25] <wiak> i have a *little* problem, my system crash/reboot while running ffmpeg randomly, it running on Ubuntu 12.04.2 LTS AMD64, 16GB DDR3, AMD A10-5800K, ASUS mb, latest git compiled ffmpeg or the latest from jon-severinsson ppa
[07:19] <ice9> how to convert webm to avi or 3gb
[07:56] <LithosLaptop> ffmpeg -i input.webm -c:v libx264 -preset slow -crf 22 -c:a libfdk_aac -vbr 4 output.3gp
[07:56] <LithosLaptop> tried that?
[07:57] <ice9> will try now
[07:58] <ubitux> dampjam: i'm not sure the single \ is enough; it might be removed by your shell
[07:58] <ice9> LithosLaptop, Unrecognized option 'c:v'
[07:58] <ice9> Failed to set value 'libx264' for option 'c:v'
[07:58] <ubitux> dampjam: that's why i used \\
[07:59] <ubitux> ice9: too old ffmpeg, use -vcodec
[07:59] <ubitux> but seriously, just upgrade.
[07:59] <ice9> now: Unrecognized option 'vbr'
[08:00] <ice9> is it vbuffer?
[08:00] <ice9> ubitux,
[08:00] <LithosLaptop> nope
[08:00] <LithosLaptop> option for libfdk_aac vbr mode
[08:00] <ice9> so what else I should use instead
[08:00] <LithosLaptop> hmm
[08:00] <LithosLaptop> try
[08:01] <LithosLaptop> ffmpeg -i input.webm -vcodec libx264 -acodec libfdk_aac -ab 128k output.3gp
[08:02] <LithosLaptop> oops forgot video bitrate
[08:04] <ice9> LithosLaptop, Unknown encoder 'libfdk_aac'
[08:04] <LithosLaptop> umm
[08:05] <ubitux> -c:a aac -strict experimental
[08:05] <ubitux> -acodec*
[08:05] <LithosLaptop> lol no
[08:05] <ubitux> good enough.
[08:06] <LithosLaptop> try libfaac firrst
[08:06] <ice9> its working now
[08:06] <ice9> lets see the result
[08:10] <LithosLaptop> ffmpeg -i input.webm -vcodec libx264 -acodec aac -strict experimental -ab 256k -cutoff 15000 output.3gp
[08:11] <LithosLaptop> you can play around with the video bitrate with -vb option
[08:11] <LithosLaptop> I don't know what it is doing now
[08:16] <ice9> it worked fine thanks
[08:17] <ice9> how can I know which a/v codecs to use when converting formats?
[08:17] <LithosLaptop> http://en.wikipedia.org/wiki/Comparison_of_container_formats
[08:18] <LithosLaptop> depends on what codecs the output container format supports
[10:02] <crypcryp> hi all
[10:02] <crypcryp> can i trim a video with ffmpeg ?
[10:03] <crypcryp> i want to trim a 5 mins video the first part .. then the end part .. then put them together
[10:36] <mittens> crypcryp: i use avidemux for cutting files
[10:37] <mittens> didnt know you could do it with ffmpeg
[10:40] <JEEB> yeah
[10:40] <JEEB> -ss and -t
[10:40] <JEEB> before -i
[10:40] <JEEB> and then -c copy to not re-encode
[10:40] <JEEB> of course this will only cut on random access points
[11:13] <dorp> Is it possible to split video streams based on I frames, accurately? ... I use ffprobe for revealing the I frames, the PTS is in the form: 29.958333 ... while ffmpeg's pattern ss[.xxx] ... is it possible to have accuracy with ,XXXXXX vs .XXX?
[12:10] <Mavrik> dorp, even a 50fps video will require only two decimals for frame timestamps in seconds.
[12:12] <dorp> Mavrik: I'm not sure if that applies to the lookup method of -ss?
[12:12] <Mavrik> dorp, you're asking a silly question,
[12:13] <Mavrik> a 50fps movie will have frames in 0.02 increments of seconds.
[12:13] <Mavrik> a 60fps will have them in 0.017
[12:14] <dorp> Mavrik: You don't see a difference between 0.017 and 0.016666666666 ?
[12:14] <Mavrik> there is none in the context you're asking.
[12:15] <Mavrik> you can always write your own demuxer that will use timebase based PTS
[12:15] <dorp> Mavrik: The manual says -ss would seek backwards, not to the 'nearest' I frame position
[12:17] <dorp> Mavrik: "ffmpeg will seek to the closest seek point before position"
[12:18] <Mavrik> ok.
[12:18] <Mavrik> you're missing the point.
[12:24] <dorp> If ffprobe indicates that the 3rd I frame position is at 29.958333, what value would -ss translate as the 3rd I frame? 30? 29.959? 29.958?
[12:25] <dorp> Obviously I can see the results for this specific case, the question is, is there any certainty for having consistency behind this conversion?
[17:32] <radl> [h264 @ 0x7fa368636fe0]Found reference and non-reference fields in the same frame, which is not implemented.
[17:32] <radl> I'm using git-2013-07-18-630fc7d, has this been fixed since?
[17:48] <durandal_1707> does it asks for sample?
[17:49] <durandal_1707> no it is not fixed
[17:50] <radl> yes, it asks for an ftp upload
[17:51] <durandal_1707> that it is reason why it asks for that
[17:51] <durandal_1707> is that file valid? (not just corrupted)
[17:54] <radl> that's what I'm wondering - it's a transport stream, so there may have been some corruption during capture
[17:54] <radl> how can I check?
[17:58] <durandal_1707> are there other decoders that can decode it better?
[18:07] <radl> Actually this may be an mplayer problem, it only happens when I split the fields to be displayed individually
[18:49] <vlt> Hello. I try to make a video from a series of png files using "ffmpeg -r 4 -i img%04d.png -f h264 counter.h264" but the resulting video has only the first image. Any idea what I did wrong?
[18:51] <durandal_1707> numbers are not in sequential order?
[18:51] <vlt> durandal_1707: Yes, they are.
[18:52] <vlt> durandal_1707: No, they aren't
[18:52] <vlt> durandal_1707: Thank you. It's a 0, 4, 8, 12 ... series.
[18:56] <durandal_1707> perhaps you can use '-pattern_type glob_sequence'
[19:03] <Partmedia> I've been reading the man pages trying to figure out how to have FFMPEG accept a raw file, with no luck.
[19:03] <durandal_1707> raw video file or?
[19:04] <Partmedia> Sorry, it's a raw PCM file, 8-bit unsigned without endianness.
[19:04] <durandal_1707> ffmpeg -f u8 -i input ....
[19:05] <durandal_1707> see: ffmpeg -h demuxer=u8
[19:05] <durandal_1707> for supported options
[19:05] <durandal_1707> eg: sample_rate and channels
[19:06] <Partmedia> hmm, I guess I was trying to use the pcm codec
[19:06] <Partmedia> thanks!
[19:07] <Partmedia> wow, this is working very well, thanks again :D
[19:33] <empee_> Hi, i've been googling this for two days now without any result (that actually works) .. mpeg-ts (dvb-t source) video with aspect ratio change mid stream.. trying to encode that into x264 and pad it so that everything is in nice 16:9 frame .. no success
[19:34] <empee_> ffprobe shows me the right sample_aspect_ratio's, 16:9 -> 64:45 and when ar changes it shows 16:15
[19:35] <durandal_1707> ok, so you want that width/height does not change or?
[19:42] <empee_> the video is normal dvb-t mpeg2 720x576 .. the problem is that both 16:9 and 4:3 are 720x576 .. so i kind of need to squeeze the x resolution on 4:3 to make it look right in the output
[19:42] <durandal_1707> aha so whatever ffmpeg do it keeps same resolution - which gives wrong output?
[19:43] <durandal_1707> well you could feature request on bug tracker and upload or link to that sample
[19:43] <durandal_1707> *open
[19:44] <empee_> http://kamm.io/~empee/ar_change.ts
[19:45] <durandal_1707> sorry, but mentioning it here will not force me to work on that problem....
[19:46] <empee_> ok.. but i dont think it's a bug..
[19:47] <durandal_1707> well if output is unnatural it is bug...
[19:49] <empee_> well it's not and it is.. since the video is actually 720x576 all the time.. just the aspect ratio changes.. i was trying to fiddle around with the pad filter & sar value to get the padding to work but couldn't get it to work
[19:49] <durandal_1707> well if there is no way, it should be, open feature request ....
[19:51] <empee_> i'll submit something to the bug tracker .. some one else was asking this a while back on the mailinglist but no one answered them
[20:00] <empee_> this is actually funny.. when i skip it with -ss to the part that is already 4:3 the output is also 4:3 but when starting couple of seconds before the output is and will be 16:9
[20:06] <empee_> is the sar value in pad filter the same as ffprobes sample_aspect_ratio and is it updated for each frame?
[20:36] <durandal_1707> empee_: it's sar of frame that is going to be filtered
[21:21] <jokoon> hello
[21:22] <jokoon> anyone knows why the transcode assistant results in no video output ?
[21:45] <empee_> ok .. so my problem isn't relly ffmpeg's problem.. now the question is resolution is already set (lets say 720x576) and i want to run scale filter to the video and if sar > 16/15 -> normal 16:9 scaling else scale width to 4:3
[21:46] <empee_> but aparently i'm not able to "scale & pad" video when ar changes?
[21:49] <Mavrik> empee_, not with just ffmpeg if you have such a source
[21:49] <Mavrik> AR is signaled as SAR only anyway which is being passed through
[21:52] <empee_> bah.. why not? .. it can scale so why can't it scale if something changes >_<
[21:53] <empee_> i can even write an if statement in the filters that should work..
[21:54] <empee_> Mavrik: what should i use then if not ffmpeg .. i'm doing realtime transcoding of dvb-t and ar change is part of this.. really wouldn't want to go to any commercial solutions
[21:55] <Mavrik> *shrug*
[21:55] <Mavrik> people paid me to write software that did realtime transcoding from DVB-T for them
[21:55] <Mavrik> didn't find any good OSS software for doing that
[21:56] <empee_> yep.. and since aparently everyone is asking money for it there's no real how-to's on the internet.. only tens of companies doing it
[21:57] <empee_> my mumudvb->ffmpeg->nginx works really well for HLS streaming but this damn ar change..
[22:00] <empee_> scale='if(lt(sar,16/15),iw/(4/3),600)':480,pad='600:480:0:0' <- that defines how to handle the 4:3 change only if it would work :(
[22:41] <durandal_1707> empee_: what it does instead?
[23:58] <gregf> how can I record audio from my mic to its own file and my video to another? I been able to record audio to a wav file but the video portion still contains the audio as well.
[00:00] --- Mon Sep  9 2013


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