[Ffmpeg-devel-irc] ffmpeg.log.20181211

[burek]

[02:00:34 CET] <tytyt> Is it possible to convert from a memory stream to a file using ffmpeg?
[02:02:40 CET] <furq> if you can pipe it into ffmpeg, sure
[02:08:48 CET] <tytyt> I'm using a wrapper right now, but does it even take in bitmaps?
[02:09:34 CET] <furq> -f rawvideo i -
[02:09:37 CET] <furq> -i -
[02:09:54 CET] <furq> or if you mean bitmaps as in .bmp files then -f image2pipe -i -
[02:10:10 CET] <tytyt> Awesome!
[02:10:15 CET] <furq> rawvideo is just raw pixel data so you'll need to specify the resolution and framerate
[02:10:56 CET] <furq> -video_size 123x456 -framerate 25 -f rawvideo -i -
[02:11:24 CET] <jin> how do i increase contrast for a mp4
[02:11:50 CET] <TheRock> you can do it in your monitor
[02:12:10 CET] <jin> no srsly
[02:12:27 CET] <furq> colorlevels, curves, eq, etc
[02:12:27 CET] <jin> looking for an example command to increase contrast
[02:12:41 CET] <furq> https://ffmpeg.org/ffmpeg-filters.html#eq
[02:14:32 CET] <jin> trying to find the most simple example
[02:14:50 CET] <jin> is 1 the default?
[02:14:53 CET] <jin> for everything?
[02:17:38 CET] <tytyt> "you can do it in your monitor"
[02:17:39 CET] <tytyt> Lol
[02:18:33 CET] <jin> idk which is more painful to learn ffmpeg or blender
[02:19:10 CET] <jin> I imagine I could write a command like:  ffmpeg -i infile -vf contrast=1.5 outfile
[02:22:30 CET] <jin> https://www.ffmpeg.org/ffmpeg-filters.html#toc-eq why is there no examples here?
[02:28:23 CET] <fred1807> where can I learn to understand the x1,y1,x2,y2 rationale for video playback croping?
[02:30:00 CET] <jin> ffmpeg -i in.mp4 -vf mp=eq2=gamma:contrast:brightness:saturation:rg:gg:bg:weight out.mp4 -y   a 3 year old commentgave this example
[02:30:32 CET] <jin> do I really have to do all the values like mp=eq=1:1.5:1:1:1:1:1:1    just to increase contrast by 50%
[02:30:50 CET] <jin> seems excessive
[02:31:01 CET] <furq> no you don't and also don't use mp
[02:31:12 CET] <furq> just -vf eq=contrast=2
[02:31:49 CET] <jin> okay and replace ffmpeg with ffplay to preview?
[02:32:05 CET] <jin> 2 = increase contrast 100%?
[02:32:47 CET] <jin> guess I'll trial and error
[02:41:05 CET] <tytyt> So, the Licence agreement for FFmpeg is not met for my project so I'm wondering if anyone has any other options for encoding to AV1 format?
[02:41:53 CET] <TheRock> why is it not met
[02:42:17 CET] <furq> you can use libaom and libwebp directly
[02:42:21 CET] <furq> those are bsd derived iirc
[02:42:39 CET] <furq> although yeah you should be able to comply with the lgpl
[02:43:14 CET] <tytyt> I was under the understanding that libaom did not support encoding.
[02:43:18 CET] <tytyt> I was just being stupid then.
[02:43:34 CET] <TheRock> linking dynamic is fine for lpgl
[02:43:38 CET] <furq> also i meant libwebm obviously
[02:43:54 CET] <tytyt> On no sorry, I meant encoding from png or bitmap.
[02:44:39 CET] <tytyt> I'm trying to encode images to AV1
[09:26:33 CET] <friendofafriend> Hello.  I've got a concatinated MP4 audio file.  When I run "ffmpeg -i inputfile -c copy outputfile", ffmpeg gives the expected output with a "Found duplicated MOOV Atom. Skipped it" warning.
[09:27:06 CET] <friendofafriend> Is there a way to split the output file where the duplicate MOOV Atom is found?
[11:18:34 CET] <RazWelles> Is nvenc supported on msys for ffmpeg?
[11:18:56 CET] <RazWelles> I'm about to open a new project but I can't tell which compiler will play nice for the two
[11:19:57 CET] <BtbN> should work. I'd recommend msvc though
[11:24:15 CET] <JEEB> msys isn't what you'd build FFmpeg with for windows, though :P
[11:24:32 CET] <JEEB> although msys2 is often the environment in which you do the building within windows (unless you're doing WSL)
[11:24:50 CET] <JEEB> because mingw-w64 is what does the (normal) windows binaries
[11:25:04 CET] <JEEB> msys(2) binaries are such that depend on msys(2)'s cygwin.dll etc
[11:25:16 CET] <JEEB> heck, I call MSVC from msys(2)'s environment, too :P
[12:07:30 CET] <RazWelles> JEEB: Oh geez I didn't even know you could do that
[12:07:41 CET] <RazWelles> msvc it is
[12:07:44 CET] <RazWelles> thank you
[14:10:23 CET] <andbubble> Hi
[14:10:30 CET] <andbubble> How can I install FFMPEG with all things enabled by default? I tried using the docker container but it doesn't have libass for subtitles
[14:11:04 CET] <andbubble> I tried with both Alpine and Ubuntu versions
[14:17:35 CET] <masterkorp> hello everyone
[14:17:59 CET] <masterkorp> I want to concatenate a series of videos, but only after a few seconds o each video, is that possible?
[14:25:17 CET] <andbubble> I disconnected, did anyone answer the question I posted about using docker or other package to get a complete FFMPEG installation with all the libraries like lib-ass
[14:30:33 CET] <mateothegreat> @andbubble: pilfer from https://github.com/jrottenberg/ffmpeg
[14:35:53 CET] <andbubble> @mateothegreat I tried using that docker container
[14:35:58 CET] <andbubble> but it doesn't have evrything enabled
[14:36:31 CET] <mateothegreat> right, so clone the Dockerfile and enable it yourself ^_^
[14:36:44 CET] <andbubble> But in the dockerifle it seems to have the part for enabling libass
[14:37:22 CET] <andbubble> ie. here: https://github.com/jrottenberg/ffmpeg/blob/master/docker-images/4.1/ubuntu/Dockerfile#L271
[14:39:49 CET] <mateothegreat> I don't understand your problem
[14:39:54 CET] <andbubble> and here https://github.com/jrottenberg/ffmpeg/blob/master/docker-images/4.1/ubuntu/Dockerfile#L328
[14:40:08 CET] <andbubble> well I went ahead, used that docker container but when I run ffmpeg --help
[14:40:13 CET] <andbubble> it doesn't show --enable-libass
[14:42:34 CET] <andbubble> see: https://hastebin.com/idetorabig.bash
[15:04:08 CET] <BtbN> You'll have a hard time enabling _everything_
[15:16:44 CET] <andbubble> Any solution to 'No usable fontconfig configuration file found, using fallback.
[15:16:54 CET] <andbubble> I don't get any subtitles burned to video
[15:40:42 CET] <Karel|> hey guys
[15:40:49 CET] <Karel|> I'm working on a C++ wrapper around the ffmpeg library
[15:41:22 CET] <Karel|> it's going quite well, but I have a few remaining issues I can't seem to fix
[15:42:03 CET] <Karel|> anyone here I could bounce some things off of?
[15:43:15 CET] <Karel|> right now I'm struggling with the mpeg2video codec
[15:43:44 CET] <Karel|> if I use the command line tool, it somehow sets the proper bit_rate somewhere in the code since the final result looks well, but in my system it doesn't
[15:43:58 CET] <Karel|> I've stepped through the entire ffmpeg.c file to figure out where it happens and I can't find it
[15:44:57 CET] <Karel|> this is the command I'm running, so nothing fancy there, just all defaults: ffmpeg.exe -i .\samples\big_buck_bunny.mp4 -c:v mpeg2video bla.mpg
[15:45:42 CET] <Karel|> nothing different in the codecContext's either, the bit_rate, global_quality etc settings are identical in my system and in ffmpeg.c
[17:51:39 CET] <visub>  when I try to write a bash script with ffmpeg to find PSNR and SSIM for multiple files I get "ffmpeg:command not found" error. the same command works fine from the terminal
[17:52:15 CET] <visub> Could someone tell me what I could be doing wrong?
[17:52:58 CET] <pink_mist> you've changed your PATH
[17:57:35 CET] <visub> Thank you:)
[18:11:41 CET] <dv_> does anybody have VP9 examples with altref frames?
[18:11:52 CET] <dv_> I have trouble finding videos with altref frames in them
[18:12:06 CET] <dv_> or dont VP9 bitstreams have invisible frames?
[18:15:48 CET] <JEEB> dv_: they have the concept at least, that's the way they kept having totally-not-bframes
[18:15:49 CET] <realies> is there any way to get more info on how a particular mp3 file is broken?
[18:16:02 CET] <realies> i think ffmpeg died because it was out of memory and it left out a partial file
[18:16:45 CET] <dv_> JEEB, and I've seen these frames in action in various VP8 streams. not in VP9 ones yet though.
[18:52:13 CET] <realies> actually I get LAME3.99.5 and many AAAAAAA chars at the end of the file, seems like it finished writing to file correctly?
[18:52:14 CET] <kepstin> realies: mp3 files are pretty simple, the only issue you might have with a partial file is some tools report the wrong length or have strange seek bar behaviour
[18:53:56 CET] <realies> ffprobe only says [warning] Estimating duration from bitrate, this may be inaccurate
[18:54:17 CET] <realies> but then the file seems to have a correct footer (just looking at the hex viewer)
[19:02:17 CET] <realies> is there any way to figure what in particular went wrong?
[20:18:29 CET] <furq> realies: you can try mp3diags
[20:43:47 CET] <jin> how do I shave 2 pixels from the top of a video?
[20:43:53 CET] <jin> off the top*
[20:46:54 CET] Action: jin searches through pages of documentation looking for an answer
[20:47:07 CET] <furq> jin: if it's h264 then you can do it without reencoding
[20:47:16 CET] <jin> oh man I already converted to webm :(
[20:47:24 CET] <jin> but thats okay
[20:47:40 CET] <furq> did you not keep the source
[20:47:44 CET] <jin> of course I did
[20:47:51 CET] <furq> ok good
[20:48:11 CET] <jin> I have a collection of videos with minor imperfections now though, a few pixels here n there I gotta shave off
[20:48:14 CET] <furq> well yeah -bsf:v h264_metadata=crop_top=2 to do it without reencoding
[20:48:23 CET] <jin> Sweet
[20:48:30 CET] <furq> otherwise -vf crop=in_w:in_h-2:0:2
[20:51:19 CET] <jin> thanks furq !
[20:51:29 CET] <jin> I think I understand crop filter a lot more now
[00:00:00 CET] --- Wed Dec 12 2018