[Ffmpeg-devel-irc] ffmpeg.log.20190104

[burek]

[00:44:34 CET] <b_jonas> hmm, so apparently I have previously encoded audio to mp3 with either (-q 4) or (-abr -b 128). I'll have to figure out what quality setting I want in the future.
[00:46:39 CET] <b_jonas> oh, but I should also experiment with mobile phones and other devices in case I can encode ogg or webm in some way that they are willing to play itt
[00:46:55 CET] <b_jonas> so far I only got these stupid mobile phones to play mp3 or lossless audio
[00:47:22 CET] <JEEB> vorbis in ogg, aac in mp4 are two things that work on  androids etc, idevices want aac in mp4
[00:48:57 CET] <b_jonas> JEEB: these phones are not smartphones and not android
[00:49:28 CET] <b_jonas> the hard part is, of course, that I would ideally like them play on future devices that I haven't even bought yet
[00:49:34 CET] <JEEB> well generally then raw mp3 or aac in mp4 are the likely things to work
[00:49:39 CET] <b_jonas> but I can make different encodes later
[00:49:49 CET] <JEEB> yes, just keep oroginsl data
[00:50:15 CET] <JEEB> since audio cds are just 1411kbps or so
[00:50:24 CET] <b_jonas> JEEB: the mobile phones can record video, so I can test what video they record, and hope they can play audio files with the same audio codec as in the video they recorded, if I just set parameters correctly
[00:50:25 CET] <JEEB> small compared to raw video data
[00:50:39 CET] <b_jonas> it gets ugly, eg. some cheap mobile phones won't even render progressive (multi-plane) jpegs
[00:50:42 CET] <b_jonas> only baseline jpegs
[00:50:43 CET] <JEEB> b_jonas: overthinking I think :)
[00:50:57 CET] <JEEB> try cbr mp3 and aac in mp4
[00:51:08 CET] <JEEB> put both onto device abd see if works
[00:51:15 CET] <JEEB> quicker to test (tm)
[00:51:18 CET] <b_jonas> JEEB: sure, or flac-compressed data because that's lossless and half or quarter of the size of the CD data
[00:51:23 CET] <JEEB> yup
[00:51:26 CET] <b_jonas> I have already tested mp3, that works
[00:51:42 CET] <b_jonas> even mp3 files that I have encoded before these phones even existed work
[00:51:59 CET] <furq> what cds are you buying that compress by 75%
[00:52:07 CET] <b_jonas> ok, I will test aac in mp4 too then
[00:52:19 CET] <b_jonas> furq: hmm, let me check the actual compression rate
[00:52:21 CET] <JEEB> -b:a aac -b:a 192k -movflags faststart and then output file as out.mp4
[00:52:33 CET] <JEEB> argh first is -c:a aac
[00:52:37 CET] <JEEB> of course :p
[00:52:41 CET] <furq> flac averages about 65% compression ratio
[00:52:53 CET] <furq> i.e. the output is 65% of the input
[00:53:25 CET] <b_jonas> darn, I deleted the cd data ... I don't want to re-read the cd, so I'll have to guess the length from the duration
[00:53:42 CET] <furq> i've got discs that are less than 50% but not many
[00:58:34 CET] <b_jonas> yes, that's probably a better approximation
[01:00:02 CET] <b_jonas> this specific album has total size of 296568832 bytes of flac, and a total duration of 2646.2 seconds
[01:00:22 CET] <b_jonas> what's the bitrate for CD audio?
[01:00:46 CET] <b_jonas> JEEB said 1411kbps
[01:01:00 CET] <JEEB> yup, something like that
[01:01:41 CET] <b_jonas> that can't work, that wouldn't fit these 45 minutes on a CD
[01:02:03 CET] <b_jonas> 2646.2 seconds would be DVD sized at that bitrate
[01:05:05 CET] <b_jonas> ah, it's 1411 kiloBITS per second
[01:05:06 CET] <b_jonas> sorry
[01:06:56 CET] <b_jonas> so the grabbed CD data is about 466789690 bytes, so flac compression rate is 63%
[01:06:58 CET] <b_jonas> you're right
[04:30:33 CET] <haasn> is it possible to "reinterpret" the video format without conversion? say I have a rgbp video that I want to "cast" to yuv444p
[04:30:51 CET] <haasn> i.e. I have an RGB video where red contains the luma information and so on
[04:31:14 CET] <haasn> I can try using something like swscale to convert from rgbp to yuv444p but this applies colorspace conversions
[04:35:12 CET] <klaxa> haasn: you can use -pix_fmt as an input option
[04:36:03 CET] <haasn> Option pixel_format not found.
[04:36:30 CET] <haasn> ffmpeg -pix_fmt yuv444p -i in.mov -c copy out.mkv
[04:36:44 CET] <klaxa> hmm... just checked with my old code, i only used it on rawvideo
[04:37:14 CET] <haasn> I would mostly be interested in an avfilter though, so I can use it with -vf in mpv
[04:37:32 CET] <haasn> extractplanes + combineplanes I guess
[04:37:43 CET] <haasn> except I have no idea how to "combine planes"
[04:38:29 CET] <haasn> ah it's called 'mergeplanes'
[04:41:12 CET] <haasn>  -lavfi-complex '[vid1] extractplanes=r+g+b [v][y][u]; [y][u][v] mergeplanes=0x001020:yuv444p [vo]'
[04:41:14 CET] <haasn> this works
[04:41:41 CET] <haasn> sort of annoying having to do it this way but at least that works
[06:01:44 CET] <hungrywolf> How do I figure out what kind of library omxplayer uses to display video to the screen, and ofcourse its audio library
[07:02:31 CET] <analogical> when I type "ffmpeg.exe -i video.mkv -c:v copy -c:a copy video.mp4" I only want to copy the video and the audio from the source file. What do I type to NOT copy the subtitles from the source file?
[09:10:05 CET] <TheAMM> analogical: -sn
[09:10:16 CET] <TheAMM> ffmpeg -i video.mkv -c copy -sn video.mp4
[09:10:49 CET] <TheAMM> -vn and -an for video/audio, there was a fourth one but I forget what it was about (metadata?)
[09:30:45 CET] <CoreX> :P
[09:30:56 CET] <CoreX> [20:14:48] <analogical> can FFmpeg be used to remove metadata and tags from videofiles?
[09:30:56 CET] <CoreX> [20:15:18] <furq> analogical: -map_metadata -1
[09:30:56 CET] <CoreX> [20:15:24] <furq> it only removes container metadata though
[09:30:56 CET] <CoreX> [20:20:42] <analogical> furq, it worked! Now how do I apply that to all the files in the same directory?
[09:30:58 CET] <CoreX> [06:02:31] <analogical> when I type "ffmpeg.exe -i video.mkv -c:v copy -c:a copy video.mp4" I only want to copy the video and the audio from the source file. What do I type to NOT copy the subtitles from the source file?
[09:31:14 CET] <CoreX> TheAMM those are the only ones he asked about from what i can see
[09:33:11 CET] <TheAMM> k
[09:34:34 CET] <analogical> I've tried lots of things but I still cant remove the subtitles from the videofile
[09:43:30 CET] <analogical> seems like I have to remux the file just to remove the subtitles
[09:43:44 CET] <analogical> with mkvtoolnix
[09:53:27 CET] <hungrywolf> This is a very small video player >> https://github.com/illuusio/ffmpeg-tutorial/blob/master/tutorial07.c
[09:53:37 CET] <hungrywolf> This is built using sdl and ffmpeg
[09:53:47 CET] <hungrywolf> but this does not work on raspberrypi 0
[09:54:01 CET] <hungrywolf> The video is too laggy
[09:54:10 CET] <hungrywolf> is there any way I can make it work on rpi0?
[16:00:24 CET] <lays147> Good afternoon guys... I am trying to convert a mxf with 8 tracks of audio to a wav file with only the audios, but apparently my code just get's the first track of the audio from the mxf to the wav. is there a way to merge them all? because some videos has audio on the second track and only the first is being used on the wav conversion
[16:16:27 CET] <DHE> you'll have to use a filter to merge multiple audio tracks into a single audio track
[16:16:54 CET] <lays147> DHE: any tips on how to do that?
[16:17:33 CET] <DHE> lays147: https://ffmpeg.org/ffmpeg-filters.html#amix   I assume you want a simple mono or stereo track that sounds like playing all audio tracks simultaneously... I dunno about mxf specifically but this might get you started
[16:20:33 CET] <lays147> DHE: you got the idea, however, the only input is one video with 8 tracks, and this amix sounds like it needs a few files for input?
[16:21:16 CET] <DHE> that's the example they provide. you can do it with one file but you'll have to build the filter_complex manually
[16:57:45 CET] <SQUelcher> Hello.
[17:09:30 CET] <SQUelcher> I've noticed that libfdk_aac got an upgrade a few days ago (0.1.6 -> 2.0.0). [ https://sourceforge.net/projects/opencore-amr/files/fdk-aac/ ] - After upgrading my library, ffmpeg doesn't seem to work with it anymore. It seems that it is trying to encode something, but everything stays in the buffer, until I quit ffmpeg. (like: [libfdk_aac @ 0x55a786462900] 613 frames left in the queue on closing). After
[17:09:36 CET] <SQUelcher> downgrading, the problem is gone. Current git also does not work with the new library.
[17:09:39 CET] <SQUelcher> Should I open a bug report about this?
[17:12:32 CET] <c_14> If there's not already an open bug report about that, yeah
[17:14:35 CET] <SQUelcher> I haven't seen one, so I will. Ok, thanks.
[19:17:00 CET] <Mavrik> um... what happened to the open broadcast encoder project or what was it? The live streaming server someone was developing?
[21:13:15 CET] <Peetz0r> Hey! I'm trying to mix some different inputs (x11grap, mjpeg stream, v4l2 device, and alsa audio) into one stream and stream that to twitch. All this on a Raspberry Pi 3A+ using h264_omx. This is now 50% working.
[21:14:42 CET] <Peetz0r> But I'm having some issues with performance and audio. I think that one of the problems might be that my mjpeg source has a very irregular framerate. Is there a way to buffer frames so that it can just do it's work at 30fps (or whatever rate I specify) amd duplicating or dropping frames whenever needed?
[21:17:08 CET] <Peetz0r> Here's my current commandline: https://paste.sigio.nl/view/45e772d7
[21:18:43 CET] <Peetz0r> (my endgoal is a portable Twitch mobile gaming setup based on 2 phones, 1 webcam, a Pi, a huge powerbank and an unlimited 4G plan)
[21:19:38 CET] <Peetz0r> Also, what would be the best CPU/GPU memory split on a 512MB Pi 3A+?
[22:17:52 CET] <Skandalist> Hello. I'm trying to capture screen with good quality with ffmpeg, but the video comes slowly out of sync with audio (I think, because of slow HDD), I was trying different formats, some are better, the others are worse. Can VFR help with that? Should I use -vsync 2 -r 25 to enable it?
[00:00:00 CET] --- Sat Jan  5 2019