[Ffmpeg-devel-irc] ffmpeg.log.20161010

[burek]

[00:18:20 CEST] <cowai> Can anyone try this? ffmpeg -i test.mkv -c copy -segment_time 10 -segment_list test.ffconcat -f segment test_00%d.mkv &&  ffmpeg -i test.ffconcat  -c copy test_concatted.mkv
[00:19:02 CEST] <cowai> test_concatted.mkv has either artifacts or gaps every 10 second.
[00:19:28 CEST] <cowai> I have tested with a bunch of formats now. and none of them works.
[00:19:35 CEST] <cowai> I am using ffmpeg 3.1.4.
[00:28:25 CEST] <MINIMAN10000> gah there are two things I can't figure out
[00:28:44 CEST] <MINIMAN10000> I might as well create a psuedocommand to try and convey what I can't do lol
[00:29:01 CEST] <MINIMAN10000> ffmpeg -r 20 -i apple.mp4 -f image2 ./apple/%d.png
[00:29:37 CEST] <MINIMAN10000> I want a video to be converted to pngs. Be numbered without leading zeros. Be placed in the relatively /apple folder
[00:30:41 CEST] <MINIMAN10000> in this case I want it to output at a rate of 20 fps while not affecting playback speed ( hopefully i at least did that part right )
[00:30:56 CEST] <MINIMAN10000> assuming it's being played back at 20 fps of course.
[00:32:23 CEST] <furq> if you want the output fps to be 20 then use -r as an output option
[00:32:27 CEST] <furq> also you don't need -f image2
[00:32:31 CEST] <furq> everything else there looks fine
[00:32:46 CEST] <MINIMAN10000> Ah that came from the wiki "The canonical form to work with image sequences is to use the -f image2 argument like this:"
[00:33:11 CEST] <furq> it'll guess that from the file extension
[00:34:18 CEST] <MINIMAN10000> Errored out http://pastebin.com/cne87Zj2
[00:34:46 CEST] <furq> you're missing a %
[00:35:37 CEST] <MINIMAN10000> it ran when I added the extra percent making that command line
[00:35:38 CEST] <MINIMAN10000> ffmpeg -r 20 -i apple.mp4 ./apple/%%d.png
[00:35:59 CEST] <MINIMAN10000> didn't know I was supposed to have 2%s to get it to work
[00:36:13 CEST] <furq> that's weird
[00:36:18 CEST] <MINIMAN10000> maybe % means something in .bat
[00:36:22 CEST] <MINIMAN10000> it could have been eating it itself
[00:36:23 CEST] <furq> oh, windows
[00:36:32 CEST] <furq> yeah your shell was probably screwing it up
[00:36:42 CEST] <agrathwohl> Is there a way, using ffprobe, to determine whether an MP4 containing an H.264 stream is constant frame rate?
[00:37:45 CEST] <MINIMAN10000> whoops forgot i want the images 47x47 lol
[00:37:48 CEST] <MINIMAN10000> i was to busy fixing the actual problems
[00:38:40 CEST] <MINIMAN10000> I shall use scale=47:47
[00:38:48 CEST] <MINIMAN10000> -vf scale that is
[00:41:47 CEST] <MINIMAN10000> lol that ended up a lot more frames and data than anticipated
[00:42:15 CEST] <MINIMAN10000> 13167 frames and 12.7 MB
[01:01:19 CEST] <iive> why 47:47 ? that's odd number
[04:07:29 CEST] <benlieb> I'm encoding video for online viewing. What AAC bitrate should I use?
[04:08:50 CEST] <klaxa> some people claim to be able to hear (and get headaches from? wow) 128 kbps aac
[04:09:13 CEST] <DHE> still, 128k would be a minimum for stereo audio
[04:26:39 CEST] <benlieb> DHE: when I convert with ffmpeg to I have to do anything specific to keep audio stereo?
[04:26:57 CEST] <benlieb> would this preserve it: ffmpeg -i input.wav -c:a aac -b:a 160k output.m4a
[04:29:01 CEST] <DHE> it'll keep the existing number of channels unless you explicit change it (with -ac)
[05:06:50 CEST] <alex88> hi there, I'm using this command 'ffmpeg -rtsp_transport tcp -i rtsp://admin:admin@192.168.1.30:554/play1.sdp -acodec aac -vcodec h264 -pix_fmt yuv420p -profile:v baseline -level 3 /tmp/test.mp4' to convert an rtsp stream to an mp4 video to show it on an ipad
[05:07:21 CEST] <alex88> however I get a gray play button and nothing happens when I tap on it, anyone has a working version of a command to load a video on the ipad?
[05:20:35 CEST] <alex88> oh nvm
[06:12:31 CEST] <Quaraxkad> how do i instruct ffmpeg to NOT use my environment http proxy?
[06:38:24 CEST] <Quaraxkad> also... is there an argument to make ffmpeg download hls streams using more than one connection thread?
[10:14:52 CEST] <mbarisa_> Is it possible to create new mp4 file(which will be just one small video segment of full length mp4 file) from mp4 http stream without downloading the whole mp4 file to disk and feeding it to mp4Parser. If any other stable java library exist which could do the sam job please point me to it.
[10:14:57 CEST] <mbarisa_> I know it can be done with ffmpeg as explained in this post but i want to avoid using full feature heavy library(cutting the mp4 file doesn't involve transcoding the video, this operation just repacks the mp4 file) for just cutting the mp4 file.
[10:15:01 CEST] <mbarisa_> ffmpeg -ss 00:01:00.000 -i "http://myfile.mp4" -t 00:02:00.000 -c:a copy -c:v copy output.mp4
[10:15:04 CEST] <mbarisa_> [10:13]
[10:15:07 CEST] <mbarisa_> ffmpeg -ss 00:01:00.000 -i "http://myfile.mp4" -t 00:02:00.000 -c:a copy -c:v copy output.mp4
[11:21:48 CEST] <cowai_> Is there any good known to work projects that uses ffmpeg to to distribute a single file encoding over several hosts ?
[11:25:02 CEST] <BtbN> no
[11:25:19 CEST] <BtbN> There is no generic way to do that.
[12:07:01 CEST] <cowai_> in theory, if I can split up a video file at exact gop boundings, I can segments individually on several machines, and then concat them together, right?
[12:07:28 CEST] <cowai_> is there a container that would work for that can handle most codecs?
[12:07:46 CEST] <cowai_> lets say the audio is DTS and I want to keep that, but rerender the video.
[12:09:03 CEST] <Infiltrator> cowai_: mkv usually handles everything.
[12:09:39 CEST] <furq> i would guess that if mpegts doesn't handle it then you've got a problem somewhere else
[12:09:54 CEST] <cowai_> Infiltrator: ffmpeg -i test.mkv -c copy -segment_time 10 -segment_list test.ffconcat -f segment test_00%d.mkv &&  ffmpeg -i test.ffconcat  -c copy test_concatted.mkv
[12:10:19 CEST] <cowai_> test_concatted.mkv always has gaps and displays errors in vlc in the messages console at the segment points
[12:10:32 CEST] <cowai_> mpegts works better, but not always.
[12:10:48 CEST] <furq> does vlc show errors with no audio
[12:11:05 CEST] <cowai_> with mkv, but not with mpegts, I think.
[12:11:15 CEST] <cowai_> let me check.
[12:14:21 CEST] <furq> it might be worth trying mpegts as the final output format as well
[12:15:25 CEST] <furq> if that doesn't work reliably with no audio then i suspect there's a bug somewhere
[12:16:41 CEST] <cowai_> I tried now with mpegts with no sound, and there is no errors. But there is a slight jump/gap at the segment points.
[12:17:02 CEST] <bencoh> which isn't good either
[12:17:34 CEST] <cowai_> is there a place for static linux builds where I can test older versions?
[12:26:56 CEST] <Spring> does the WebM container support soft subtitles? Or only hard encoded subs?
[12:28:04 CEST] <furq> webvtt is part of the webm spec, but it's not clear if it's supported yet
[12:29:50 CEST] <furq> looks like it isn't
[12:29:57 CEST] <furq> https://trac.ffmpeg.org/ticket/5434
[12:32:01 CEST] <furq> cowai_: it should be easy enough to build old versions of ffmpeg yourself
[12:32:11 CEST] <furq> if you're not encoding anything then you don't need any external libs
[12:35:18 CEST] <cowai_> The end goal is the encode too,
[12:35:46 CEST] <cowai_> I am creating a small script to show my problems more clearly.
[12:36:00 CEST] <cowai_> Care to take a look when I am finished?
[12:36:20 CEST] <furq> sure
[12:36:50 CEST] <furq> even if you need to encode you can probably just use your system's libx264
[12:39:38 CEST] <Spring> furq, so "officially" WebM doesn't subs but there is a proposal to have it added even so?
[12:40:14 CEST] <furq> officially it will support subs, but it doesn't yet
[13:18:52 CEST] <cowai_> furq: http://pastebin.com/pVPcGJZR
[13:19:20 CEST] <cowai_> not the best source to test with, but you will see errors and a small gap too in vlc.
[13:19:52 CEST] <cowai_> put ffmpeg=ffmpeg in the second line of the script if you dont want to get the static build referenced.
[13:54:07 CEST] <mbarisa> Is it possible to create new mp4 file(which will be just one small video segment of full length mp4 file) from mp4 http stream without downloading the whole mp4 file to disk and feeding it to mp4Parser. If any other stable java library exist which could do the sam job please point me to it.
[13:54:12 CEST] <mbarisa> I know it can be done with ffmpeg as explained in this post but i want to avoid using full feature heavy library(cutting the mp4 file doesn't involve transcoding the video, this operation just repacks the mp4 file) for just cutting the mp4 file.
[13:54:16 CEST] <mbarisa> ffmpeg -ss 00:01:00.000 -i "http://myfile.mp4" -t 00:02:00.000 -c:a copy -c:v copy output.mp4
[13:54:19 CEST] <mbarisa> [10:13]
[13:54:22 CEST] <mbarisa> ffmpeg -ss 00:01:00.000 -i "http://myfile.mp4" -t 00:02:00.000 -c:a copy -c:v copy output.mp4
[13:55:42 CEST] <mbarisa> this works, but it is inexact
[13:56:06 CEST] <mbarisa> when I use encoding, it is too slow for cache-ing part of video
[13:56:35 CEST] <mbarisa> and using like this it is fast and works, but it fails 1-2-3 seconds, depending where I cut
[14:21:22 CEST] <cowai_> furq: Care to look at my script?
[14:26:38 CEST] <fqtw> im rendering my webcam stream using opengl, now i want to use libffmpeg to do datamoshing on my webcam stream before it is rendered. datamoshing is done by removing i-frames at certain times, so i have to encode webcam frames into AVPackets and then skip them when packet->pict_type == AV_PICTURE_TYPE_I. but which frame should i use instead when i dont use the current i-frame?
[14:27:22 CEST] <fqtw> http://forum.glitchet.com/t/tutorial-make-video-glitch-art-how-to-datamosh-in-plain-english/36
[14:28:38 CEST] <fqtw> https://i.imgur.com/pXNEjHO.gif
[14:29:53 CEST] <fqtw> should i just duplicate the last frame?
[14:30:02 CEST] <fqtw> the one before the i-frame?
[14:32:22 CEST] <BtbN> fqtw, there is no libffmpeg
[14:32:27 CEST] <BtbN> there is libav*
[14:32:36 CEST] <fqtw> BtbN: thats what i mean
[14:32:54 CEST] <BtbN> Ok, just making sure. There have been plenty people trying to compile ffmpeg.c as a library.
[14:37:52 CEST] <Quaraxkad> is there an argument to make ffmpeg download hls streams using more than one connection/thread?
[14:38:22 CEST] <BtbN> no
[15:12:12 CEST] <cowai_> Anybody know of a custom solution to distribute encoding of a file on multiple machines on linux?
[15:43:50 CEST] <flux> of a single file?
[15:44:27 CEST] <flux> I used condor for distributing encodings of multiple files to condor clients that share the same nfs mount for data
[15:45:07 CEST] <flux> I guess it would just be a matter of preprocessing to distirbute a single file (ie. a new condor job that take the file, splits it into parts, submits jobs to encode parts, waits for results, submits a job to join the parts)
[15:48:59 CEST] <cowai_> flux: single file yes.
[15:50:03 CEST] <cowai_> I have spent many hours this weekend trying just that. The problem is that when I stich parts back together, there are small gaps inbetween.
[15:50:28 CEST] <cowai_> I have dts sound and i want to just stream copy that.
[15:50:28 CEST] <flux> that's probably because the segments don't start and stop exactly the same time
[15:50:50 CEST] <flux> ok, so you encode only video and remove audio from the video first?
[15:50:54 CEST] <cowai_> well, I havent found a portable way to produce that.
[15:50:58 CEST] <flux> I guess my theory falls apart then :)
[15:51:06 CEST] <cowai_> I have tried everything mate ;)
[15:51:08 CEST] <flux> howo do you split them?
[15:51:15 CEST] <cowai_> -f segment -an
[15:51:35 CEST] <flux> hmm, ok
[15:51:48 CEST] <cowai_> also tried manually with -ss -to pts_time that I know are key frames
[15:51:57 CEST] <flux> well I guess you could compare the outputs of ffprobe -show_streams before and after your operation to see where it goes wrong
[15:52:02 CEST] <flux> and even to individual segemnts
[15:52:10 CEST] <flux> then complain to the mailing list if you have a reproducible test case ;-)
[15:56:55 CEST] <elliotd123> Hi guys, I'm looking at a live UDP stream with ffmpeg and showing lower fps on output than the input framerate. No discontinuities, so it doesn't appear to be packet loss. What else could cause this?
[16:05:36 CEST] <jkqxz> elliotd123:  Any of the framerate controls may drop frames (-r options, filters), and the A/V sync code can do it too (add "-vsync passthrough" to switch that off).
[16:08:10 CEST] <BtbN> Are you transcoding, and it can't keep up?
[16:14:05 CEST] <elliotd123> well I see the issue when I just transcode to null, but it's definitely not a cpu starvation issue. I'll try the vsync passthrough to see if that helps
[16:17:50 CEST] <elliotd123> jkqxz: I'll also note that I see this even when there aren't any framerate controls specified. Are there any by default?
[16:19:09 CEST] <elliotd123> jkqxz: It looks like with "-vsync passthrough" I'm still seeing the low fps (It's 58, input is 59.94, so it's not significantly lower)
[16:19:27 CEST] <BtbN> elliotd123, are you specifying -c copy?
[16:19:37 CEST] <BtbN> Because otherwise it will pointlessly transcode
[16:19:54 CEST] <elliotd123> "ffmpeg -i udp://@239.1.1.6:59006 -f null -vsync passthrough /dev/null"
[16:20:02 CEST] <BtbN> yes, that's transcoding.
[16:20:32 CEST] <BtbN> just do -c copy -f null -
[16:20:38 CEST] <BtbN> and see how fast that goes.
[16:20:59 CEST] <elliotd123> ok I'm trying with "-c copy" - so if this works, then there must be some issue on the transcoding side?
[16:21:24 CEST] <BtbN> Transcoding is slow, your CPU might just not be up to it. And it's pointless, unless you actually want to transcode.
[16:22:46 CEST] <elliotd123> Yeah we want to transcode, actually our client wants to transcode, so I'm not sure the exact format, etc, so I'll have to find that out
[16:23:19 CEST] <elliotd123> looks like that might be it though. Still, we're showing <40% CPU usage on the host
[16:23:54 CEST] <BtbN> might be just one or two cores maxed out
[16:24:08 CEST] <elliotd123> yep
[16:24:55 CEST] <elliotd123> Is the transcode process multithreaded though?
[16:25:19 CEST] <BtbN> ffmpeg is strictly single threaded. Threading only happens within a codec/filter.
[16:28:16 CEST] <elliotd123> Wait I'm still seeing the issue actually. Must be intermittent? Is it possible for the framerate to change?
[16:35:11 CEST] <elliotd123> yeah it sits fine for a while at 60-61fps and then drops to 56-58 or so, sometimes lower by what I can see
[16:37:29 CEST] <BtbN> Seems like normal fluctioations to me.
[16:39:36 CEST] <shapsuk> Hey guys  Im an iOS developer and looking at using FFmpeg in my app so that I can support additional formats  however Im very new to the library and not sure how to get started. Ive managed to get the lib built for iOS and I can successfully call things like avcodecs_license()  so Ive definitely got it all built and imported so that I can access it from my code (Swift)
[16:39:36 CEST] <shapsuk> What Id really like is to start with something simple, like play a file from disk that I know doesnt normally work on iOS natively. Its a short movie clip that uses an Apple Pro-Res codec. It works in things like VLC so Im fairly certain FFmpeg should work fine.
[16:39:37 CEST] <shapsuk> Any help would be appreciated.
[16:41:38 CEST] <elliotd123> BtbN: Yeah, I just have to figure out how to communicate that with our client
[16:43:21 CEST] <BtbN> It's probably 59.94 FPS, and with network jitter, the ocassional dropped packet, and buffering, it jumps around a bit.
[16:43:58 CEST] <elliotd123> dropped packet will give us a discontinuity error, and haven't received a single one of those. I don't expect much network jitter either, since it's all on the same switched LAN
[16:50:44 CEST] <shapsuk> Is this the right channel to ask that question? Sorry, dont want to be a nuisance
[16:51:57 CEST] <sfan5> yes this is the correch channel
[16:52:55 CEST] <sfan5> shapsuk: try taking a look at these: https://github.com/FFmpeg/FFmpeg/tree/master/doc/examples
[16:54:31 CEST] <shapsuk> Great thanks  I missed those  do you know if there are Obj-C or Swift examples around?
[16:54:53 CEST] <shapsuk> these looks great either way
[16:55:21 CEST] <BtbN> ffmpeg is C, any only C.
[16:56:55 CEST] <sfan5> also note that ffmpeg will only assist you in reading the video file, not in presenting it
[16:57:28 CEST] <shapsuk> @sfan5 yeah I realise that  I mistyped before
[16:58:21 CEST] <shapsuk> ok C is fine. I can always create some simple wrappers around the stuff I need, similar to these examples actually.
[16:58:58 CEST] <shapsuk> is it ok if I ask a couple more questions& just some stuff Id like cleared up
[16:59:57 CEST] <shapsuk> first off, I understand FFmpeg should be able to read the data, my question here is in what format does it give it back to me? Since Im on iOS, ideally I need to get CVPixelBuffers or CMSampleBuffers
[17:01:45 CEST] <BtbN> If you only decode, you get a frame with whatever pixel format is native to the decoder, usually yuv420p or nv12 in case of hardware decoders.
[17:01:57 CEST] <shapsuk> My second question is in regards to VideoToolbox  specifically VTDecompression  I saw references all over about this and if Ive understood correctly, FFmpeg should automatically use this when its available? Do you know if it uses the hardware acceleration even for files that are not H.264?
[17:02:10 CEST] <BtbN> ffmpeg.c does at least.
[17:05:39 CEST] <shapsuk> right, so when I get back the data, I should be able to allocate a new pixelBuffer with that pixelFormat (ideally) and get the frame from it?
[17:07:38 CEST] <shapsuk> is it possible to ask the decoder to return a specific pixel format (assuming its supported) ?
[17:08:59 CEST] <jkqxz> libavcodec decodes into normal memory (just a big array of bytes).  If you can make your iOS thing look like normal memory then you can decode straight into it, but if not you will need to create your thing out of the memory region afterwards (which may involve a copy).
[17:09:25 CEST] <shapsuk> right
[17:09:32 CEST] <jkqxz> Yes the pixel format is settable, but most decoders will only give you one choice there.
[17:09:41 CEST] <shapsuk> ah ok
[17:11:36 CEST] <shapsuk> to decode my movie files, should I be using libavcodec? I thought I needed lbavformat and have been looking into that. The movie files is an .mov file with Pro-Res codec
[17:12:42 CEST] <bencoh> libavformat contains demuxers / parsers, libavcodec holds decoders
[17:12:43 CEST] <jkqxz> libavformat reads the container (the mov file format), libavcodec decodes the video inside it (the prores stream).
[17:15:52 CEST] <shapsuk> oh  so does that mean I need to start with libavformat in order to read the file?
[17:16:06 CEST] <shapsuk> hmm.. getting confused. Maybe the examples will help here
[17:20:03 CEST] <shapsuk> sorry  I had to switch devices
[17:22:01 CEST] <someperson234789> Hey -- I've been trying to google for a little while now. Hoping someone can point me in the right direction. I'm getting "chunked" audio when doing a no-op pad filter. http://pastebin.com/Kgh4wfMA
[17:48:26 CEST] <benbro> is there a way to tell if mp4 file index is at the start (faststart) or end?
[17:50:36 CEST] <jkqxz> Cut the file in half and try to play it.  If it works, then it's at the start.
[17:51:04 CEST] <benbro> jkqxz: how do I cut the file in half?
[17:52:44 CEST] <bencoh> :D
[17:53:05 CEST] <jkqxz> "dd if=file_to_test.mp4 of=tmp.mp4 count=10000", then play tmp.mp4.  (Cuts the first 50MB out, reduce the count if the file is smaller.)
[17:53:53 CEST] <benbro> thanks
[17:53:58 CEST] <furq> benbro: mp4box -info
[17:53:58 CEST] <jkqxz> (While it works, that answer is somewhat silly.  There is probably a proper way to do it...)
[17:55:49 CEST] <benbro> pip install qtfaststart
[17:55:55 CEST] <benbro> qtfaststart -l video.mp4
[17:56:09 CEST] <benbro> if the moov atom is after the mdat atom, it's bad
[17:56:38 CEST] <benbro> thanks
[17:56:46 CEST] <furq> on which note
[17:56:52 CEST] <shapsuk> sorry -- jumped in and out of some meetings and then realised my devices kept switching.
[17:56:52 CEST] <shapsuk> if I have an .mov file, can I pass this directly to libavcodec or do I need to do something first with libavformat?
[17:56:53 CEST] <benbro> http://superuser.com/a/559532
[17:56:54 CEST] <shapsuk> I only see one decode example on the examples page and its not dealing with a container type
[17:57:05 CEST] <furq> is there a way of moving the moov atom that doesn't involve rewriting the whole file to disk
[17:57:14 CEST] <benlieb> I've heard that h264 / aac is the combination that will play in the largest number of browsers. Does the aac encoder matter? In my library of videos I see various: aac (LC), aac (libfdk_aac) etc
[17:57:24 CEST] <furq> benlieb: makes no difference
[17:57:32 CEST] <furq> what might matter is aac-lc vs aac-he
[17:57:47 CEST] <furq> lc is more widely supported
[17:59:21 CEST] <benlieb> furq: I"m not sure what those are
[17:59:32 CEST] <benlieb> does that affect me?
[17:59:35 CEST] <furq> https://en.wikipedia.org/wiki/High-Efficiency_Advanced_Audio_Coding
[18:00:32 CEST] <benlieb> would that show up as aac-le as the audio encoding?
[18:01:21 CEST] <benlieb> I have over 8,000 vids in my company library, created over 10 years, I'm trying to get them "ready" for online viewing instead of the older "download" model. It's a bit daunting.
[18:01:22 CEST] <jkqxz> shapsuk:  The demuxing_decoding example is probably the one you want.
[18:01:48 CEST] <benlieb> furq: ^
[18:02:06 CEST] <furq>     Stream #0:0(und): Audio: aac (HE-AAC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 48 kb/s (default)
[18:02:10 CEST] <furq> it should should up as something like that
[18:02:47 CEST] <furq> he-aac is fairly widely supported though
[18:03:37 CEST] <furq> very old iOS devices might not handle it properly
[18:04:01 CEST] <furq> every android device and every desktop browser should handle it fine
[18:04:19 CEST] <benlieb> furq: I'm probably not going to worry about finding any old vids with that encoder if it's new.
[18:04:56 CEST] <benlieb> furq: is libfdk_aac a good choice for converting old non-aac videos, and encoding new ones moving forward?
[18:05:03 CEST] <furq> it's the best aac encoder in ffmpeg
[18:05:45 CEST] <furq> unless you're on osx in which case i think you can use apple aac through videotoolbox
[18:06:11 CEST] <benlieb> furq: best in what way? My real concern is user compatibility and longevity of compatibility
[18:06:23 CEST] <furq> the encoder makes no difference for compatibility
[18:06:33 CEST] <furq> as long as it produces a compliant aac bitstream, they're all the same
[18:07:26 CEST] <furq> fdk is (probably) the highest quality at a given bitrate
[18:07:47 CEST] <furq> other than closed-source encoders which aren't in ffmpeg
[18:09:49 CEST] <shapsuk> jkqxz: thanks
[18:11:00 CEST] <shapsuk> I've managed to get the codec loaded into a context
[18:11:05 CEST] <shapsuk> what exactly is the contet?
[18:11:07 CEST] <shapsuk> what exactly is the context?
[18:14:18 CEST] <BtbN> The native aac encoder is perfectly fine though
[18:14:26 CEST] <BtbN> you are not going to hear a difference
[18:19:00 CEST] <benlieb> furq: so aac (LC) is ok?
[18:19:26 CEST] <furq> yes
[18:20:16 CEST] <furq> aac anything is probably fine
[18:25:40 CEST] <shapsuk> jkqxz: when configuring the context, am I specifying the details of the input file? I might not know the input file details, like frame-rate. I assumed these would be auto discovered?
[18:31:04 CEST] <maziar> how to record from RTMP to 1080p mp4
[18:32:20 CEST] <shapsuk> can anyone confirm for me whether or not the decoders are hardware accelerated on iOS since VideoToolbox is now available ?
[18:35:12 CEST] <BtbN> The VideoToolbox decoder is probably using VideoToolbox.
[18:47:15 CEST] <someperson234789> huh. I changed output to .mov instead of .mkv and problem's gone.
[19:21:19 CEST] <asdbimbajos> greetings
[19:21:25 CEST] <asdbimbajos> is there anyone
[19:21:27 CEST] <asdbimbajos> ?
[19:51:40 CEST] <shapsuk> Hey guys.
[19:52:57 CEST] <shapsuk_> I'm currently using av_register_all() but wondering if this is expensive. Memory perhaps?
[19:54:18 CEST] <shapsuk__> Wondering if I should instead load only what I need?
[19:54:27 CEST] <kepstin> unless you're on a really-memory-limited system, not enough to matter
[19:55:35 CEST] <kepstin> if you know you only need a few specific codecs, it certainly won't hurt to register only the needed ones, but otherwise...
[19:56:34 CEST] <shapsuk___> Any advice appreciated
[19:58:09 CEST] <shapsuk___> FYI if anyone else comes along asking for a great little tutorial they can easily follow along with send them here
[19:58:11 CEST] <shapsuk___> http://dranger.com/ffmpeg/tutorial01.html
[19:58:21 CEST] <shapsuk___> I found this today. Very useful
[20:16:21 CEST] <bindwolf> greetings
[22:16:11 CEST] <kibibyte> hi
[22:16:17 CEST] <kibibyte> i ahev question
[22:17:16 CEST] <kibibyte> ffmpeg inputfile -acodec copy -vcodec copy output.mp4
[22:17:24 CEST] <kibibyte> how oes it know which code to use ?
[22:17:34 CEST] <kibibyte> how does it know which codec to use ?
[22:17:45 CEST] <kibibyte> copy is not codec
[22:23:55 CEST] <CoJaBo> ..?
[22:24:27 CEST] <kibibyte> CoJaBo, in manual -acodec is option for setting codec
[22:24:38 CEST] <kibibyte> what "copy" then
[22:24:41 CEST] <kibibyte> s
[22:24:54 CEST] <CoJaBo> Copy just copys the stream
[22:25:06 CEST] <CoJaBo> (without transcoding)
[22:25:19 CEST] <kibibyte> so ffmpeg inputfile -acodec copy -vcodec copy output.mp4
[22:25:28 CEST] <kibibyte> its just copies file ?
[22:25:53 CEST] <CoJaBo> Basically; I think some call that "remuxing"; it copies it to a new container, but without reencoding any of the streams
[22:26:38 CEST] <DHE> and it's usually fast enough that the disk itself is the bottleneck
[22:26:52 CEST] <DHE> but it lets you convert .avi to mp4, or mkv to webm, etc
[22:26:53 CEST] <CoJaBo> Doing that is useful to convert e.g., MP4 to MKV or vice-versa (assuming the codecs are all supported in the target container)
[22:27:34 CEST] <kibibyte> but how does it know that i want convert input to mp4
[22:27:43 CEST] <kibibyte> from output extension ?
[22:27:44 CEST] <DHE> because you named the result output.mp4
[22:27:46 CEST] <CoJaBo> The file extension sets the container format
[22:27:51 CEST] <kibibyte> ohh
[22:27:53 CEST] <CoJaBo> -f can be used to override it tho
[22:28:21 CEST] <CoJaBo> (tho it's pretty rare to actually need -f, unless you're piping stuff)
[22:30:43 CEST] <kibibyte> ok thx
[23:08:12 CEST] <LeoB> Hello! I need help!
[23:08:53 CEST] <LeoB> I am capturing a h264 video stream from a IP Camera using OpenCV ffmpeg videoIO
[23:09:16 CEST] <LeoB> it reads frames using av_read_frame
[23:10:08 CEST] <LeoB> my main problem is that I have not enought processing power to deal with all frames
[23:11:24 CEST] <LeoB> is there a way to capture from a h264 stream, only picking the latest captured frame?
[23:11:35 CEST] <BtbN> no
[23:11:46 CEST] <BtbN> unless it's IFrame-Only, which is unlikely.
[23:12:07 CEST] <BtbN> but what kind of underpowered device are you on that can't even decode h264?
[23:13:17 CEST] <LeoB> I am on a Core i5, but I do much image processing on the same thread
[23:14:50 CEST] <BtbN> move that to a diffrent thread then
[23:15:25 CEST] <LeoB> It would be fine, but I need to deal with 4 cameras, (one on each thread)
[23:15:55 CEST] <LeoB> having a thread for each camera would be very expensive
[23:16:57 CEST] <BtbN> each h264 decoder spawns one thread for each (virtual) core anyway
[23:17:17 CEST] <BtbN> At least I think it does, I'm actually not 100% sure if the h264 decoder is multi threaded.
[23:18:24 CEST] <BtbN> yes, it supports at least slice threading.
[23:20:14 CEST] <LeoB> It should do more parallell work then
[23:20:26 CEST] <LeoB> for me it's like only one thread is being used
[23:20:51 CEST] <LeoB> (one processor core, not thread)
[23:21:39 CEST] <BtbN> Well, all the threads are doing nothing while you are busy in opencv
[23:21:50 CEST] <furq> isn't that desirable if you're capturing from four devices
[23:23:00 CEST] <LeoB> true,
[23:30:58 CEST] <nyuszika7h> how do I find out the audio bitrate in a video if neither MediaInfo nor ffprobe show it?
[23:31:02 CEST] <nyuszika7h> it was encoded with libfaac
[23:35:18 CEST] <furq> are you using the latest mediainfo
[23:36:14 CEST] <furq> support for getting stream bitrates in mkv with >1 vbr stream was added relatively recently
[23:36:23 CEST] <furq> failing that you could just demux the stream
[23:37:15 CEST] <nyuszika7h> hmm I'm still on 0.7.87, will update
[23:37:53 CEST] <nyuszika7h> 0.7.89 still doesn't show it
[23:38:27 CEST] <nyuszika7h> even when demuxed it only tells me it's VBR
[23:38:36 CEST] <nyuszika7h> but actually I can play that in foobar2000 and that gives me some idea
[00:00:00 CEST] --- Tue Oct 11 2016