[Ffmpeg-devel-irc] ffmpeg.log.20150422

Thu Apr 23 02:05:01 CEST 2015

[00:29:24 CEST] <DusteD> I have a videofile and around 9000 images (all same dimensions), the first image is a map, the rest of  a "dot", I'm trying to think of the most reasonable tactic for overlaying the map-image, and then the correct dot-image onto the video. The video is 60 fps, and the images are 5 fps.
[00:29:47 CEST] <DusteD> My first instinct is to extract all frames from the video as single images and use imagemagick and bash scripting
[00:30:17 CEST] <DusteD> but, I'm wondering if maybe there is a more intelligent way, like, converting all the images to a video first, and overlaying the two videos
[01:48:56 CEST] <kyleogrg> what's a good way to change a encode a video with square pixels?
[01:49:19 CEST] <kyleogrg> my source video is ntsc and isn't square
[01:50:31 CEST] <kyleogrg> One source says to use "scale=iw*sar:ih".  is this good?
[02:38:26 CEST] <kyleogrg> is there any reason to use high444 profile for x264?
[02:43:13 CEST] <klaxa> larger colorspace
[02:45:24 CEST] <kyleogrg> klaxa: if i'm converting from NTSC DV-AVI to MP4, do you think high444 will produce any noticeable improvement?
[02:46:06 CEST] <klaxa> depends on the content
[02:46:26 CEST] <klaxa> and depends on the source
[02:46:51 CEST] <klaxa> do some test encodes and judge for yourself
[02:46:56 CEST] <kyleogrg> ok
[02:47:10 CEST] <kyleogrg> and technically speaking, will this profile produce a smaller file?
[02:47:34 CEST] <klaxa> would probably be larger
[02:47:58 CEST] <kyleogrg> all right
[02:48:02 CEST] <klaxa> but i have no idea, the easiest way to find out is by doing two encodes with the same setting
[02:48:10 CEST] <klaxa> except for the profile
[03:00:57 CEST] <kyleogrg> if my source video is 4:1:1 chroma subsampling, is there any reason to convert it using the high444 profile?
[03:40:19 CEST] <Prelude2004c> sup everyone.. good evening.. having trouble passing a ffmpeg -i < input  > -vcopy and -acopy -f mpegts udp://destination:port ... < --- this causes artifacts i guess because some UDP traffic is missed on the network. Over a distance i guess this is not the best way to pull data.
[03:40:28 CEST] <Prelude2004c> anyone know a better way without transcoding it at source ?
[03:40:41 CEST] <Prelude2004c> maybe somehow with little horsepower i can push it via TCP or something
[03:40:51 CEST] <Prelude2004c> that way if a packet doesn't arrive it gets retransmitted
[03:40:56 CEST] <Prelude2004c> i want to make sure our stream is clean
[03:41:00 CEST] <Prelude2004c> so i can encode it properly
[03:41:02 CEST] <Prelude2004c> any ideas ?
[03:52:21 CEST] <Prelude2004c> can anyone help?
[03:58:14 CEST] <klaxa> Prelude2004c:
[03:58:15 CEST] <klaxa> Apr 19 00:41:53 <klaxa>	you can use http if you are using a single client and a single server
[03:58:16 CEST] <klaxa> Apr 19 00:42:37 <klaxa>	Prelude2004c: https://ffmpeg.org/ffmpeg-all.html#http
[03:58:16 CEST] <klaxa> Apr 19 00:42:41 <klaxa>	see: listen option
[03:58:16 CEST] <klaxa> Apr 19 00:43:53 <klaxa>	or tcp: https://ffmpeg.org/ffmpeg-all.html#tcp
[04:01:57 CEST] <Prelude2004c> cool, let me try it ..
[04:02:02 CEST] <Prelude2004c> never knew about ogg
[04:04:57 CEST] <Prelude2004c> http://22.22.22.22:5003: Cannot assign requested address
[04:04:57 CEST] <Prelude2004c> [root at ts-stream ~]# ffmpeg -i udp://239.255.10.10:5000 -c copy  -listen 1 -f ogg http://22.22.22.22:5003
[04:05:04 CEST] <Prelude2004c> what does it mean ?
[04:14:18 CEST] <Prelude2004c> the server:port .. is that localhost ?
[04:14:28 CEST] <Prelude2004c> or can it be a remote url?
[08:05:22 CEST] <Prelude2004c> hey , anyone here ? why all my videos look funny if i don't deinterlace
[08:08:42 CEST] <botnut> hi all - never used ffmpeg/ffserver before - but can ffserver be used to stream a video source to many people - keep in mind I would prefer that the video source not be from a file - but rather a stream itself to ffserver in mpjeg format - also this is a live feed
[08:10:00 CEST] <Prelude2004c> why dn't you just output  to a local port like RTMP .
[08:10:18 CEST] <Prelude2004c> or better yet, output HLS segments and then it will use adaptive bit rate straming
[08:11:00 CEST] <botnut> the source is coming from a raspberry pi using picamera - it was hard to get it to go real time as is - but we did - now the trick is getting that stream over to a broadcasting server of some sort
[08:12:36 CEST] <Prelude2004c> hwo to you view the source right now?
[08:13:01 CEST] <botnut> we open vlc and connect to the pi directly - however - this won't be an option because we want to have this fed on the web with many clients
[08:13:28 CEST] <Prelude2004c> you can use VLC to outout
[08:13:39 CEST] <Prelude2004c> why don't you output rtmp > wowza server and then have that serve all the customers
[08:14:02 CEST] <botnut> hrmmmm
[08:14:19 CEST] <Prelude2004c> vlc i am not sure can do segmenting but it probably can..
[08:14:36 CEST] <Prelude2004c> then just dump the files to a directory people can access
[08:14:44 CEST] <Prelude2004c> but wowza is popular
[08:15:13 CEST] <botnut> the idea of dumping it to the file system indicates to me we will have lag of 1-3 seconds or so
[08:15:20 CEST] <botnut> would prefer as near real time as possible
[08:15:37 CEST] <botnut> there is no need to go back in time and see previous video - just the current feed
[11:00:08 CEST] <aleb> How can I get the frame numbers for the frames which contain the full picture (not the diff since the previous frame)?
[11:02:20 CEST] <Anoia> I frames (vs incremental P Frames)
[11:31:51 CEST] <aleb> And how do I print the list of frames?
[12:55:58 CEST] <aleb> $ ffprobe -i x.MTS -show_frames -of csv | grep frame,video
[12:55:58 CEST] <aleb> frame,video,1,37456,0.416178,37456,0.416178,37456,0.416178,1800,0.020000,768,129895,1920,1080,yuv420p,1:1,I,0,0,0,0,0
[14:52:08 CEST] <Fyr> could anyone tell me what genre Christmas carols have?
[17:29:39 CEST] <squeegily> I have an MP4 which is 240x134. I want to: scale it to 512px wide, then "crop" it to 512px high (centered), with a transparent background, and save it as a GIF.. I can't figure out how to do it, though
[17:30:07 CEST] <squeegily> I'm stuck on ffmpeg -i $MP4 -vf "scale=512:-1" $GIF
[17:30:48 CEST] <squeegily> I took a look at https://trac.ffmpeg.org/wiki/Scaling%20%28resizing%29%20with%20ffmpeg but I'm not understanding the cropbox thing
[17:30:52 CEST] <c_14> -vf scale=w=512:h=-2,crop=h=512:w=iw
[17:35:29 CEST] <squeegily> Invalid too big or non positive size for width '512' or height '512'
[17:36:28 CEST] <squeegily> Maybe "crop" is the wrong word.. The GIMP equivalent of what I want to do is Canvas Size, <increase>, Center
[17:36:46 CEST] <squeegily> I want to "un-crop" the image to reveal a transparent background
[17:36:50 CEST] <c_14> You want to make it bigger?
[17:36:51 CEST] <c_14> pad
[17:37:23 CEST] <squeegily> pad worked.. how do I center the image?
[17:37:43 CEST] <c_14> x=iw/2:y=ih/2
[17:37:49 CEST] <c_14> wait
[17:37:59 CEST] <c_14> x=(ow-iw)/2:y=(oh-ih)/2
[17:38:03 CEST] <squeegily> Also, how do i make the background transparent instead of black?
[17:38:40 CEST] <c_14> :color=black at 0
[17:38:41 CEST] <sfan5> you can have a transparent background, but you can't save transparency into gifs
[17:38:48 CEST] <squeegily> Why not?
[17:38:54 CEST] <squeegily> Is a bug report open for that?
[17:39:01 CEST] <sfan5> because GIF doesn't support that
[17:39:28 CEST] <squeegily> sfan5: What does GIMP use for transparent GIFs then? Other image viewers and browsers seem to view them fine
[17:40:23 CEST] <squeegily> ..I thought
[17:41:08 CEST] <sfan5> ...
[17:41:11 CEST] <sfan5> I don't know
[17:41:56 CEST] <squeegily> Yeah I just tested it by taking a GIF outputted by ffmpeg, opening it in GIMP, adding an alpha channel, and re-exporting
[17:41:58 CEST] <sfan5> GIF doesn't support transparency, so GIMP is doing something but not saving transparency
[17:42:31 CEST] <squeegily> That transparency showed up in my browser and image viewer and when re-opened in Gimp
[17:42:40 CEST] <squeegily> I suspect it's legitimate
[17:42:59 CEST] <squeegily> "test.gif: GIF image data, version 89a, 512x512"
[17:43:15 CEST] <sfan5> could you upload some gif with transparency somewhere?
[17:43:27 CEST] <sfan5> I don't know what GIMP does to save transparency
[17:44:06 CEST] <squeegily> I had this book on HTML4 that mentioned that Photoshop was able to save to a high enough GIF standard to support it or something like that
[17:44:15 CEST] <squeegily> It was a really old book, I don't know if I have it anymore
[17:44:27 CEST] <squeegily> But that means GIFs have probably supported it forever
[17:44:33 CEST] <squeegily> Anyway, here's the image: http://a.uguu.se/fiuxrv_test.gif
[17:45:05 CEST] <squeegily> 1 sec I broke the animation
[17:45:21 CEST] <sfan5> i meant a transparent gif
[17:45:30 CEST] <sfan5> but i did it myself with gimp
[17:45:30 CEST] <sfan5> and now I'm confused
[17:45:33 CEST] <squeegily> Check the bototm half of the image
[17:46:06 CEST] <sfan5> it's transparent...
[17:47:19 CEST] <squeegily> Here's one with a hole in his face for clarity: http://a.uguu.se/ccqwrn_test.gif
[17:47:34 CEST] <sfan5> ahh
[17:47:51 CEST] <sfan5> apparently gifs can have an 1-bit alpha channel
[17:47:56 CEST] <squeegily> The GIF ffmpeg outputted had transparency properly set on every frame except a single one
[17:48:24 CEST] <squeegily> Just the first frame lacked an alpha channel; I could have simply removed that frame to fix the animation
[17:48:43 CEST] <squeegily> Since it set the color for every pixel which was never later overwritten
[17:49:03 CEST] <squeegily> So it seems ffmpeg does support gif transparency 90% of the way
[18:13:23 CEST] <capradmar> I post that on SO: http://stackoverflow.com/questions/29773692/ffmpeg-crashes-on-startup-upon-release-deployement
[18:13:28 CEST] <capradmar> any idea?
[20:14:01 CEST] <faLUCE> Hell, how can I cut the first 3.5 seconds of myfile.mp3 ?
[20:25:06 CEST] <sfan5> faLUCE: if you want just the 3.5s: ffmpeg -i myfile.mp3 -t 00:00:03.500 output.wav if you want everything after 3.5s: ffmpeg -ss 00:00:03.500 -i myfile.mp3 -ss 0 output.wav
[20:47:34 CEST] <faLUCE> sfan5: thanks
[21:08:55 CEST] <kyleogrg> Hello
[21:09:10 CEST] <kyleogrg> Aside from this IRC channel, there is also a mailing list for support, right?
[21:09:30 CEST] <c_14> yes
[21:10:23 CEST] <kyleogrg> Is that what this is? https://ffmpeg.org/pipermail/ffmpeg-user/2011-November/003203.html
[21:10:32 CEST] <kyleogrg> (for example)
[21:10:33 CEST] <llogan> ffmpeg-user
[21:10:36 CEST] <llogan> http://ffmpeg.org/contact.html
[21:11:09 CEST] <llogan> make sure to provide your actual command and the complete console output.
[21:11:17 CEST] <kyleogrg> okay
[21:11:37 CEST] <llogan> if you do not subscribe then you will have to wait for moderator approval. usually less than 24 hrs.
[21:11:53 CEST] <kyleogrg> So that's the place to go if I need support (other than here)?
[21:12:17 CEST] <llogan> yes. here and ffmpeg-user ML are the two official user support methods
[21:13:08 CEST] <kyleogrg> is there a cleaner way to view these ffmpeg-user threads?  like an html version?
[21:13:20 CEST] <llogan> the link you provided is HTML
[21:13:32 CEST] <llogan> but some people may prefer third party viewers like nabble or gmane
[21:13:41 CEST] <kyleogrg> yes.  well, like... i don't know
[21:13:47 CEST] <kyleogrg> something that looks like a forum
[21:13:56 CEST] <kyleogrg> maybe it's just me, but it's hard to read
[21:14:10 CEST] <kyleogrg> things all run together.  lots of >>>>>>>>>>
[21:14:23 CEST] <llogan> http://news.gmane.org/gmane.comp.video.ffmpeg.user
[21:14:27 CEST] <llogan> http://ffmpeg-users.933282.n4.nabble.com/
[21:14:57 CEST] <kyleogrg> ah, thanks a lot
[21:17:13 CEST] <kyleogrg> i like the second link
[21:17:17 CEST] <kyleogrg> just what i was looking for
[21:20:10 CEST] <llogan> more ML info: https://trac.ffmpeg.org/wiki/MailingListEtiquette
[21:22:04 CEST] <kyleogrg> thanks, i'll look at it
[21:36:09 CEST] <CooKieLord> Hi! I'm just wondering if I'm in the right place for a question with regards to how to use the FFMPEG library in C++ code
[21:42:43 CEST] <c_14> Well, you're not in the wrong place at least. Whether or not someone is currently around who can help you is another question. The best bet is to ask and wait to see if someone can help you, and/or ask on the libav-user at ffmpeg.org ml.
[21:43:12 CEST] <CooKieLord> Awesome thanks
[21:47:50 CEST] <kyleogrg> Okay, I want to concatenate many chunks of a video file into one.
[21:48:06 CEST] <kyleogrg> they are numbered 1 to 178
[21:48:40 CEST] <kepstin-laptop> kyleogrg, you'd probably want to write a script that generates your ffmpeg command then.
[21:48:44 CEST] <kyleogrg> rather than writing out "concat:001.blah|002.blah|003.blah" and so on...
[21:48:55 CEST] <kyleogrg> exactly!  but how?
[21:49:18 CEST] <kepstin-laptop> if you're using linux, it's a pretty trivial shell script. if you're using windows... well, i can't help you there ;)
[21:49:38 CEST] <kyleogrg> I simply need to concat all the *.blah files in a folder.  they are already in order, so that won't be a problem
[21:49:40 CEST] <llogan> you probably can't use the concat protocol
[21:49:49 CEST] <kyleogrg> llogan: why not?
[21:50:11 CEST] <llogan> it's for "cat friendly" formats. you probably need the concat demuxer or concat filter
[21:50:14 CEST] <kyleogrg> these are actually chunks of a video stream which can just be joined together
[21:50:39 CEST] <kyleogrg> basically I was using Ripbot264 to encode a x265 (yes x265) video
[21:50:46 CEST] <llogan> if it works for you then go ahead and use it
[21:51:05 CEST] <kyleogrg> it made many chunks, but the batch file to join them failed
[21:51:26 CEST] <kyleogrg> yeah.  but how can i just say "use all the files in this folder"?
[21:51:57 CEST] <llogan> some examples here https://trac.ffmpeg.org/wiki/Concatenate
[21:51:58 CEST] <kyleogrg> i thought i remember there being a simple solution
[21:52:40 CEST] <kyleogrg> hmm ok
[21:53:15 CEST] <kyleogrg> thanks
[21:56:44 CEST] <CooKieLord> Are there examples or documentation anywhere on how to properly reset the decoder in C++ if we get into an inconsistent state?
[21:57:11 CEST] <CooKieLord> The examples on how to use avcodec_decode_video2 that I can find are very optimistic and don't really show how to handle errors.
[22:02:22 CEST] <kyleogrg> okay, trying to concat, i'm getting "unable to find a suitable output format for 'output.265'"
[22:02:55 CEST] <kyleogrg> these are all .265 files, chunks which need to be concatenated
[22:03:06 CEST] <kyleogrg> and i'm saying "-c:v copy"
[22:07:21 CEST] <kyleogrg> all righty.  now stream copying to output.mp4.  this seems to be working (it's still going), but for every file chunk, I'm getting "pts has no value"
[22:37:26 CEST] <hunternet93> how do i convert a video from .mov to .mp4 without re-encoding the mov's h.264 video stream?
[22:44:18 CEST] <c_14> -c:v copy
[23:22:50 CEST] <kyleogrg> i used ffmpeg to mux a x265 stream and AAC stream to MP4
[23:22:59 CEST] <kyleogrg> but the audio seems to gradually get out of sync
[23:23:04 CEST] <kyleogrg> any clues?
[23:23:48 CEST] <kyleogrg> I did something like: ffmpeg.exe -i "input.265" -i "input2.aac" -c:v copy -c:a copy output.mp4
[23:24:46 CEST] <kyleogrg> and ffmpeg wanted me at add (something like) aac_adtstoasc to the command line
[23:25:03 CEST] <BtbN> If the input files are entirely without meningfull timestamps, that's not too surprising.
[23:25:43 CEST] <kyleogrg> yeah
[23:25:54 CEST] <kyleogrg> what can you recommend as a solution?
[23:26:35 CEST] <kyleogrg> i don't know how to add timestamps or anything like that
[23:26:36 CEST] <BtbN> Don't use raw files.
[23:26:42 CEST] <kyleogrg> sure
[23:26:52 CEST] <kyleogrg> but i'm just experimenting with this particular file
[23:27:09 CEST] <BtbN> The offset changing over time propably means ffmpeg makes a wrong guess about the framerate
[23:27:11 CEST] <kyleogrg> a certain distributed encoding program generated all these .265 chunks
[23:27:36 CEST] <kyleogrg> ok
[23:27:58 CEST] <BtbN> Or samplerate
[23:28:02 CEST] <kyleogrg> although mediainfo (idk if i should trust it) says the output file is 23.976 frames (which is correct)
[23:28:06 CEST] <BtbN> Not sure if it also has to guess that
[23:28:25 CEST] <BtbN> What does ffprobe say about the file?
[23:28:30 CEST] <BtbN> mediainfo is not ffmpeg.
[23:30:32 CEST] <kyleogrg> for the .265 stream, it says: 24.17 fps, 23.98 tbr, 1200k tbn, 23.98 tbc
[23:31:32 CEST] <kyleogrg> for the aac stream, it says: Duration: 03:02:43.53, bitrate: 316 kb/s
[23:31:32 CEST] <kyleogrg>   Stream #0:0: Audio: aac (LC), 48000 Hz, 5.1, fltp, 316 kb/s
[23:32:07 CEST] <kyleogrg> the .265 stream reports no duration or bitrate in ffprobe
[23:32:27 CEST] <BtbN> Well, 24.17 fps clearly sounds like a bad guess
[23:33:18 CEST] <kyleogrg> and as i mux again here, it says: Estimating duration from bitrate, this may be inaccurate
[23:33:39 CEST] <kyleogrg> for the aac
[23:33:39 CEST] <BtbN> Which is why you don't use raw files, they are lacking a lot of vital information.
[23:33:44 CEST] <kyleogrg> yeah
[23:34:11 CEST] <BtbN> Just play with the video framerate, i'd guess it's just wrong.
[23:34:22 CEST] <kyleogrg> i'll try it, thanks
[00:00:00 CEST] --- Thu Apr 23 2015