[Ffmpeg-devel-irc] ffmpeg.log.20180910

[burek]

[05:08:11 CEST] <fling> Which filter is for dark frame subtraction?
[06:11:37 CEST] <Elronnd> I'm trying to concatenate a bunch of videos
[06:12:05 CEST] <Elronnd> I did  'ffmpeg -f concat -i ls.txt -c copy out.mov', but in the output file, mpv gets stuck on the end of the first video
[06:15:41 CEST] <Elronnd> (also, the resultant file is 30 minutes, which is way too long)
[06:17:10 CEST] <poutine> Elronnd, Were all the videos you're concatenating encoded with the same parameters?
[06:49:20 CEST] <Elronnd> poutine: sorry for the delay, I believe they were
[06:51:56 CEST] <ariyasu> check the input files with ffprobe or mediainfo to make sure they are the same
[16:56:30 CEST] <AnrDaemon> I don't quite get, why it would not pad the stream.
[16:57:05 CEST] <AnrDaemon> https://pastebin.com/0BxrQLMh
[16:57:45 CEST] <AnrDaemon> The thing is, it does pad mp4, but not webm or jpeg.
[16:57:57 CEST] <AnrDaemon> Same command(filter) is used.
[17:03:52 CEST] <AnrDaemon> Padding well if I render preview. :/
[17:04:02 CEST] <AnrDaemon> (192:112)
[17:51:59 CEST] <capitalbra876> hey guys, im trying to stream via RTMP with ffmpeg and i'm running into a problem. is it fine if i post my stackoverflow link in here?
[18:07:38 CEST] <Hello71> sure, but probably nobody will read it
[18:11:22 CEST] <capitalbra876> alright lets hope someone does :D https://stackoverflow.com/questions/52259378/ffmpeg-video-codec-ansi-not-compatible-with-flv
[18:13:09 CEST] <DHE> sounds like you need to specify "-f concat" ahead of the input file or you didn't put the needed autodetection header on the text file
[18:33:27 CEST] <relaxed> capitalbra876: ffmpeg thinks your input is the text file itself, no the list it contains
[18:33:56 CEST] <relaxed> not*
[18:34:43 CEST] <capitalbra876> yeah im dumb
[18:35:07 CEST] <capitalbra876> seems like i lost the -f concat inbetween all the copy pasting from google
[18:37:44 CEST] <capitalbra876> okay so next problem: -stream loop -1 doesnt do what its supposed to do.  i get the following error: https://pastebin.com/PpMjwQhN
[18:38:49 CEST] <capitalbra876> it goes through the list once, without any problems, but at the end of the last video i get that error
[18:44:34 CEST] <relaxed> for that to work you probably have to concat before streaming
[18:45:25 CEST] <scramblez> Hi All, I stripped the audio channel out of a ts stream which looked like this: "Stream #0:1[0xca](eng): Audio: aac_latm (LC) ([17][0][0][0] / 0x0011), 48000 Hz, stereo, fltp" and ended up with a 6c audio: " Stream #0:0(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, 5.1, fltp, 341 kb/s (default)" Would you know why the stereo was converted into surround sound? If I play this on a system which can
[18:45:31 CEST] <scramblez> only play stereo, will I lose any part of the audio?
[18:46:32 CEST] <scramblez> The codec:a I used was mp4a and saved the audio as .m4a
[18:46:45 CEST] <DHE> it's supposed to downmix, though depending on the hardware if it doesn't know what your speaker setup is you might not hear some sound
[18:46:56 CEST] <DHE> take another look at the source. there may have been multiple audio streams in it
[18:47:27 CEST] <capitalbra876> @relaxed how would that work? just output the concat into a single file and stream that?
[18:49:14 CEST] <scramblez> Thanks DHE, there were 4 streams in the mpegts file: #0:0 video, the #0:1 audio I showed above, #0:2, which was " Unknown: none ([17][0][0][0] / 0x0011) (visual impaired)" and #0:3 for dvd_subtitle.
[18:49:47 CEST] <relaxed> capitalbra876: correct
[18:51:59 CEST] <scramblez> DHE: what confused me is why would a aac_latm (LC) stereo convert into a 5.1c when using the mp4a codec? Should I use something different?
[18:52:34 CEST] <relaxed> scramblez: pastebin.com the command and ffmpeg's output so we can see what's going on
[18:52:43 CEST] <DHE> the codec doesn't change the channel layout. that said live broadcasts do strange things sometimes
[18:54:00 CEST] <scramblez> Hmm ... I've lost the command from the shell history :(
[18:54:04 CEST] <scramblez> Will try again.
[19:02:42 CEST] <scramblez> Oops!  Sorry for the noise guys. Just checked the ts file again.  It starts as stereo. mpv tells me: "AO: [pulse] 48000Hz stereo 2ch float". This is what ffprobe declares too.  Then after the TV adverts and what not the main program is no longer stereo, but ... "AO: [pulse] 48000Hz 5.1 6ch float".
[19:02:56 CEST] <DHE> called it
[19:03:34 CEST] <scramblez> So, my extracted audio is as it ought to be.
[19:05:25 CEST] <scramblez> If I were to downmix this with ffmpeg, is it merely a matter of specifying '-ac 2', or would something more complicated be required?
[19:07:46 CEST] <DHE> that should be sufficient
[19:09:08 CEST] <scramblez> Great, thank you!
[22:58:39 CEST] <GuiToris> hey, I sometimes edit videos with ffmpeg. is there any better way to do this? I usually do: ffmpeg -i video1.MTS -ss 5 -to 10 -c copy 1.MTS; ffmpeg -i video2.MTS -ss 20 -to 30 -c copy 2.MTS; ffmpeg -i video2.MTS -ss 40 -to 50 -c copy 3.MTS; for f in ./*.wav; do echo "file '$f'" >> mylist.txt; done; ffmpeg -f concat -safe 0 -i mylist.txt -c:v libx265 -crf 30 -preset veryslow -codec:a libvorbis output.mkv
[22:59:30 CEST] <nicolas17> I think the concat demuxer lets you set start/end timestamps for each video
[23:02:55 CEST] <GuiToris> I'll check it
[23:26:39 CEST] <AnrDaemon> Any idea why padding would not work for webm and jpeg output?
[23:27:50 CEST] <AnrDaemon> https://pastebin.com/0BxrQLMh
[23:28:27 CEST] <AnrDaemon> Works for mp4 (padding 1px/2px), but for webm and jpeg, there's all 3px at the bottom.
[23:45:38 CEST] <kepstin> not sure what you mean by "doesn't work". could be rounding differences in the aspect ratio? I'd have to see the ffmpeg output.
[23:45:59 CEST] <kepstin> for both a "working" and "not working" case, ideally
[23:50:55 CEST] <GuiToris> nicolas17, I haven't found this timestamps thing, are you sure concat demuxer has it?
[23:51:22 CEST] <nicolas17> inpoint and outpoint in the .ffconcat file
[23:51:55 CEST] <GuiToris> searching, thank you
[23:52:26 CEST] <GuiToris> yes, I found inpoint and outpoint parameters
[23:52:33 CEST] <furq> https://www.ffmpeg.org/ffmpeg-formats.html#concat-1
[23:53:26 CEST] <GuiToris> yes, I was reading the wrong page ( https://trac.ffmpeg.org/wiki/Concatenate#demuxer )
[23:58:33 CEST] <hans_> how can i tell ffmpeg to output as a jpg regadless of the output filename?
[23:59:08 CEST] <hans_> ah nvm, seems the answer is -c:v:1 jpg
[00:00:00 CEST] --- Tue Sep 11 2018