[Ffmpeg-devel-irc] ffmpeg.log.20180712

[burek]

[02:03:45 CEST] <Polochon_street> Hey! I'm trying to make a spectrogram out of what my audio card is playing, and I've managed to put the spectrogram into a video file, but any idea how I could directly play it in a window?
[02:03:49 CEST] <Polochon_street> right now, I have:
[02:03:50 CEST] <Polochon_street> ffmpeg -f pulse -i alsa_output.usb-DAC_FOR_USB_FOCAL_XS-00.analog-stereo.monitor -filter_complex "showspectrum=s=1280x480:scale=log" coucou.avi
[02:11:01 CEST] <Polochon_street> okay, it works doing ffmpeg -f pulse -i alsa_output.usb-DAC_FOR_USB_FOCAL_XS-00.analog-stereo.monitor -filter_complex "showspectrum=scale=log" -f matroska - | ffplay -
[02:11:06 CEST] <Polochon_street> but I have 2s of latency for some reason
[02:11:28 CEST] <furq> matroska defaults to x264
[02:11:36 CEST] <furq> you probably want -c:v rawvideo
[02:11:47 CEST] <furq> and ffplay -fflags nobuffer or mpv --cache=no
[02:12:03 CEST] <furq> or --no-cache rather
[02:13:07 CEST] <Polochon_street> furq: you mean, dropping the -f matroska?
[02:13:12 CEST] <furq> no keep that
[02:13:21 CEST] <furq> or -f nut
[02:13:25 CEST] <Polochon_street> ffplay -fflags nobuffer adds 5 seconds of delay for some reason
[02:14:25 CEST] <Polochon_street> okay, it works fine with the nobufer + nut, thanks :)
[02:14:36 CEST] <Polochon_street> obviously, the video quality sucks a bit, but I can probably manage
[02:15:58 CEST] <furq> it shouldn't suck with rawvideo
[02:16:09 CEST] <furq> unless it's just ffplay generally looking shit
[02:16:14 CEST] <furq> it'll do that on account of it's not very good
[02:16:34 CEST] <Polochon_street> I used -f nut, but I don't know where to put the -c:v rawvideo :x
[02:16:47 CEST] <furq> between the input and the output
[02:17:25 CEST] <Polochon_street> indeed
[02:17:28 CEST] <Polochon_street> thanks! :D
[02:33:55 CEST] <chocolate-elvis> hey, I have a client who needs a mpeg-2 program stream with a specific GOP structure such as IBBPBBPBBPBBPBB, and needs to be M=3, N=15. anyone have a clue as to how to specify this? possible?
[02:56:36 CEST] <furq> if M is bframes and N is gop size then -bf 3 -g 15
[03:00:40 CEST] <DHE> I thought it was number of bframes in which case shouldn't it be 2 for that pattern?
[03:02:48 CEST] <chocolate-elvis> thanks for that!
[03:12:03 CEST] <chocolate-elvis> DHE I think you're correct
[06:08:48 CEST] <kepstin> also make sure you leave -b_strategy at the default value 0. Values >0 enable dynamic B frame modes that'll make it not strictly follow the sequence you want.
[06:10:59 CEST] <kepstin> is that GOP structure you want in PTS order?
[06:14:20 CEST] <kepstin> it must be, if the inital sequence is IBBP
[10:11:32 CEST] <Nacht> Am I correct to assume NetVC isn't a new codec on it's own, but only IETF selecting either Dalaa, Thor or AV1 to be their official codec ?
[10:34:46 CEST] <erwu> Hello ;-)
[10:41:27 CEST] <erwu> I
[10:41:57 CEST] <erwu> I'm having some problem with ffmpeg understanding: https://stackoverflow.com/questions/51295370/stream-frame-from-video-to-pipeline-and-publish-it-to-http-mjpeg-via-ffmpeg  anyone ever challenged similar task ?
[10:43:20 CEST] <squ> you have to split project into questions
[10:43:23 CEST] <squ> and ask
[10:48:48 CEST] <erwu> I have 2 main problems : Creation of pipe under windows and communication with it from C++ level. I guess that cv::VideoWriter can handle that task. But to be honest It's a bit unclear for me how can I define pipes.
[12:05:50 CEST] <King_DuckZ> 'morning
[12:13:06 CEST] <King_DuckZ> I got a debug build of ffmpeg 3.3.7 yesterday, and stepping inside av_frame_get_buffer() I could see that buffers inside the data[] array only get allocated if the pixel format has certain flags set
[12:13:57 CEST] <King_DuckZ> frame.c:208 - if (desc->flags & AV_PIX_FMT_FLAG_PAL || desc->flags & AV_PIX_FMT_FLAG_PSEUDOPAL) {
[12:14:56 CEST] <King_DuckZ> so I don't understand... was that intended behaviour in 3.3? if so, what do I have to set my buffer formats to, so that all the necessary buffers get allocated correctly?
[12:20:21 CEST] <King_DuckZ> or is align=0 the thing causing all the troubles here? should I just set that to 16 or something?
[13:52:08 CEST] <King_DuckZ> anything to say about my findings, anyone?
[16:06:37 CEST] <King_DuckZ> anyone around?
[16:07:10 CEST] <Nacht> Yes, but I have no idea what the C code all does
[16:07:47 CEST] <King_DuckZ> :(
[16:13:44 CEST] <atomnuker> King_DuckZ: check your build, no, no and no, none of this is intended, the API is identical between 3 and 4
[16:13:56 CEST] <atomnuker> alignment does nothing
[16:15:56 CEST] <atomnuker> and make sure your frame->format is something sane and not a hardware frame
[16:17:29 CEST] <King_DuckZ> atomnuker: yet setting align to 16 fixes my crash - if you look at the code align=0 causes most code in that function to be skipped
[16:18:23 CEST] <King_DuckZ> I tried some formats but I had no luck, the one I've settled on to is 0 I think... let me find it in my code...
[16:19:04 CEST] <King_DuckZ> YUV420P
[16:19:38 CEST] <King_DuckZ> which again, works with ffmpeg 4.0.1
[16:21:20 CEST] <atomnuker> what are the width and height?
[16:22:36 CEST] <atomnuker> if alignment fixes the issues you can use the value from av_cpu_max_align()
[16:22:44 CEST] <atomnuker> which is the default alignment in case align is 0
[16:24:16 CEST] <King_DuckZ> width=3280 height=1550 but I think I tried other values as well, like 1024x512
[16:24:23 CEST] <King_DuckZ> ok, I'll set it to that then
[19:55:01 CEST] <ksk> hola
[19:57:37 CEST] <ksk> I try to convert some mp3 to lower quality, which has worked countless times for me, using this simple setup: "ffmpeg -i "${input}" -codec:a libmp3lame -b:a 48k -ac 1  "${output}"
[19:57:40 CEST] <ksk> "
[19:58:27 CEST] <ksk> however, when I use it on specific input ffmpeg starts, but does not count any bytes and does not write anything (though it is running). The input in question is the following: http://paste.debian.net/1033456/ (ffmpeg -i output)
[19:58:31 CEST] <ksk> any Idea whats wrong?
[20:17:00 CEST] <ksk> mhhm, I added "-codec:v copy" and now its transcoding.
[20:17:16 CEST] <ksk> iirc I had mp3s with covers attached in the past, but these went fine without any of this.
[21:14:21 CEST] <new2ffmpeg> Hi all
[21:14:26 CEST] <new2ffmpeg> I am new to ffmpeg
[21:15:02 CEST] <new2ffmpeg> I tried to convert a mkv file to mp4 file. ffmpeg -i input.mkv -c copy ouput.mp4
[21:15:26 CEST] <new2ffmpeg> I get the following
[21:15:46 CEST] <new2ffmpeg> Could not find codec parameters for stream 1 (Video: mjpeg, none(bt470bg/unknown/unknown), 1920x1080): unspecified pixel format Consider increasing the value for the 'analyzeduration' and 'probesize' options
[21:16:09 CEST] <new2ffmpeg> Can someone help me through this?
[21:20:12 CEST] <ChocolateArmpits> new2ffmpeg, you can try doing it like it says
[21:21:07 CEST] <ChocolateArmpits> put this before -i:  -analyzeduration 20000000
[21:21:09 CEST] <atomnuker> its a broken file, blame mp4
[21:21:41 CEST] <kepstin> the input is mkv tho?
[21:23:34 CEST] <atomnuker> well its still somewhat broken if it doesn't get probed properly
[21:25:22 CEST] <new2ffmpeg> I included -analyzeduration 20000000
[21:25:38 CEST] <new2ffmpeg> I got the following
[21:25:39 CEST] <new2ffmpeg> Stream #1: not enough frames to estimate rate; consider increasing probesize
[21:25:55 CEST] <ChocolateArmpits> if 20 seconds isn't enough then nothing is
[21:26:07 CEST] <ChocolateArmpits> new2ffmpeg, does the file play anywhere?
[21:26:19 CEST] <new2ffmpeg> It plays on VLC
[21:26:38 CEST] <ChocolateArmpits> what is your version of ffmpeg ?
[21:27:09 CEST] <new2ffmpeg> 4.0.1 on a Mac
[21:27:56 CEST] <ChocolateArmpits> How big is the file, do you know the bitrate?
[21:28:03 CEST] <furq> new2ffmpeg: did you try increasing probesize
[21:28:24 CEST] <ChocolateArmpits> instead of analyzeduration try -probesize 40000000
[21:28:29 CEST] <furq> well no set both
[21:28:35 CEST] <furq> it'll stop at whichever is lower
[21:28:58 CEST] <ChocolateArmpits> I treat them separately myself
[21:39:44 CEST] <new2ffmpeg> The file is ~600MB in size
[21:41:13 CEST] <new2ffmpeg> I tried that
[21:41:16 CEST] <new2ffmpeg> got the smae
[21:41:17 CEST] <new2ffmpeg> same
[21:41:19 CEST] <new2ffmpeg> ffmpeg -analyzeduration 20000000 -probesize 40000000 -i Truck_FreewaySample1.mkv -c copy truck_n.mp4 ffmpeg version 4.0.1 Copyright (c) 2000-2018 the FFmpeg developers   built with Apple LLVM version 9.1.0 (clang-902.0.39.2)   configuration: --prefix=/usr/local/Cellar/ffmpeg/4.0.1 --enable-shared --enable-pthreads --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-gp
[21:41:36 CEST] <new2ffmpeg> Sorry
[21:41:37 CEST] <new2ffmpeg> [matroska,webm @ 0x7ffe78808e00] Could not find codec parameters for stream 1 (Video: mjpeg, none(bt470bg/unknown/unknown), 1920x1080): unspecified pixel format Consider increasing the value for the 'analyzeduration' and 'probesize' options
[22:11:18 CEST] <Hello71> sounds like the input file is broken
[22:53:32 CEST] <wlfgang> any pointers on doing hw-accelerated h264 encoding via the API?
[00:00:00 CEST] --- Fri Jul 13 2018