[Ffmpeg-devel-irc] ffmpeg.log.20181021

[burek]

[02:27:38 CEST] <nicolas17> my theory was right, the video is just remuxed
[02:28:12 CEST] <nicolas17> I see stuff like consecutive audio and video frames being swapped, audio dts and pts being slightly different... but frame hashes all match
[05:12:45 CEST] <KombuchaKip> Hey everyone. The ffmpeg pastebin subdomain isn't working for me, so I posted my question on migrating from an older libav API to ffmpeg 4 here: https://pastebin.com/Ezp8sNVE
[11:21:34 CEST] <stn616> is this ffmpeg support
[11:22:17 CEST] <fella> Topic for #ffmpeg: Welcome to the FFmpeg USER support channel
[11:28:05 CEST] <stn616> sorry I know this is not arecord but hw:1 is not recording, a search on the interwebs told me to use dump-hw-params but I got a lot of formats, so I have no idea which should I use as -sample-fmt
[11:29:56 CEST] <stn616> I'm using a focusrite interface which in the box reads can process 24bit/192khz which is what I want
[11:30:44 CEST] <stn616> I only have alsamixer not pulse
[11:55:59 CEST] <stn616> ok... so should I choose little endian or big endian?
[18:27:14 CEST] <Accord> is it possible to stream in real time from one file to another on my local disk?
[18:27:43 CEST] <Accord> I've got this script which reads from a wav file which under normal circumstances is written to in real time
[18:27:50 CEST] <Accord> I want to simulate this if possible
[18:31:07 CEST] <Accord> nvm, found it
[18:42:13 CEST] <vifino> Hey. I made a small program using the libav* C APIs. Converts anything into a format of mine. https://github.com/shinyblink/fhconvs/blob/master/src/2fh.c
[18:43:05 CEST] <vifino> Running into bottlenecks though. After setting the codec context to be multithreaded, sws_scale is one of the major bottlenecks.
[18:43:55 CEST] <vifino> Any simple way to do frame-based multithreading with sws_scale?
[18:44:35 CEST] <vifino> Latency is no problem here, so slice-based threading is not needed. Order is, obviously.
[18:49:33 CEST] <furq> nothing in lavfi supports frame threading iirc
[18:50:34 CEST] <atomnuker> vifino: you can do your own threading by separating the sws from the decoding loop
[18:56:25 CEST] <vifino> alright. so i'd avcodec_receive_frame into a bunch of different frames, call sws_scale on them in a thread pool of sorts?
[18:57:10 CEST] <vifino> is the SwContext threadsafe?
[19:03:29 CEST] <atomnuker> not sure, but contexts are cheap
[20:20:58 CEST] <TheWild> hello
[20:21:51 CEST] <TheWild> how to trim zeroes from beginning and end of .wav files (just like picture auto-crop by color)?
[20:25:03 CEST] <furq> !filter silenceremove @TheWild
[20:25:03 CEST] <nfobot> TheWild: http://ffmpeg.org/ffmpeg-filters.html#silenceremove
[20:33:25 CEST] <TheWild> thank you. I haven't tested it yet but after deeper reading it seems to be exactly what I was searching for.hunting precisely for zeroes.
[20:34:20 CEST] <TheWild> interesting is that filter accepts named arguments, but at this link someone defined it like silenceremove=1:0:-50dB    https://stackoverflow.com/questions/25697596/using-ffmpeg-with-silencedetect-to-remove-audio-silence
[20:34:41 CEST] <furq> you can use either with any filter
[20:35:06 CEST] <furq> or a combination of the two
[20:35:07 CEST] <TheWild> ah, those are the *first* three arguments
[20:35:11 CEST] <furq> yeah
[20:35:24 CEST] <TheWild> thanks
[20:36:44 CEST] <TheWild> I regret I didn't know ffmpeg a couple of years ago. For one school presentation I had a badly scaled video (with really thick black border) and not even commercial software could fix that, lol.
[21:13:27 CEST] <durandal_1707> TheWild: use named arguments always, as i added more options to that filter in latest master
[21:14:06 CEST] <durandal_1707> also for removing silence at and you need also areverse filter twice
[21:14:13 CEST] <durandal_1707> s/and/end
[22:58:47 CEST] <mixfix41> bent
[22:58:54 CEST] <mixfix41> oh wrong window
[23:17:56 CEST] <mixfix41> ?oh the ffmpeg documentation for capturing x11 on desktop it uses quite a bit a space but i broguth taht up in here once before i shuold sign up for ffmpeg forum and post o
[00:00:00 CEST] --- Mon Oct 22 2018