[Ffmpeg-devel-irc] ffmpeg.log.20190809

[burek]

[05:16:18 CEST] <Jook> any ffmpeg dev here?
[06:40:36 CEST] <nicolas17> is aom-av1 single-threaded?
[06:41:09 CEST] <nicolas17> speed=0.0136x lol
[06:44:22 CEST] <another> you can add tiles for more multithreading
[06:46:11 CEST] <nicolas17> 35 frames (in 6 minutes) and it didn't write anything yet, bah I wanted to see the bitrate so far
[06:48:01 CEST] <another> you can also tweak -cpu-used
[06:48:49 CEST] <nicolas17> how damn big is this buffer? when can I expect it to write something to disk? >.>
[06:49:51 CEST] <another> also: make sure you have a recent version aom libaom
[06:49:59 CEST] <another> *of
[06:51:17 CEST] <another> there have been a lot of speedups since 1.0.0
[06:52:43 CEST] <nicolas17> I think the sunk cost fallacy is stopping me from Ctrl-Cing and trying tiles/mt
[06:55:29 CEST] <another> you can also segment your input and encode multiple segments at the same time to better utilise multiple cores
[07:05:05 CEST] <nicolas17> finally wrote something
[07:05:17 CEST] <nicolas17> another: that sounds interesting, how would I concatenate the segments though?
[07:07:39 CEST] <nicolas17> concat demuxer?
[07:18:28 CEST] <MontyCarleau> Hey all, I'm using -map_channel to map each channel to its own file, but I'd like to only create files for channels that exist.
[07:19:56 CEST] <MontyCarleau> -map_channel 0.0.0 ch0.wav -map_channel 0.0.1 ch1.wav will work fine for a stereo file, but it will fail for a mono file. Adding a ? after 0.0.1 will let it pass, but a (potentially large) empty file will be created if the input is mono.
[09:17:04 CEST] <machtl> hi guys... i need some help with metadata passing in udp streams
[09:17:57 CEST] <machtl> i need concat multiple files and output it to -f mpegts udp://
[09:18:39 CEST] <machtl> now i want to parse the console output of ffplay and get what file is currently playing
[09:19:56 CEST] <machtl> therefore i would need to be able to somehow insert changing metadata or concat somehow some characters to ffplay which will be pushed to the console
[09:20:15 CEST] <machtl> i wouldnt mind using -loglevel debug for this
[11:02:31 CEST] <safinaskar> is there some video player for linux, which can play video backwards?
[11:02:53 CEST] <safinaskar> support for all codecs is not important. if it supports at least one video format, this is OK
[11:03:30 CEST] <safinaskar> i need playback in both directions. i. e. i want to play video, then pause at any moment, then start playing backward, then switch to forward playing etc
[11:03:50 CEST] <safinaskar> frame-by-frame is not enough, i need real backward playing
[11:05:28 CEST] <safinaskar> currently i use this: i convert video into "rawvideo" using ffmpeg. then i convert this "rawvideo" into *.ppm.xz images using hand-written C++ program (this program spawns xz binary for every frame)
[11:06:00 CEST] <safinaskar> then i play this bunch of *.ppm.xz files using my own hand-written C++ player, which renders every frame into linux TTY framebuffer
[11:06:15 CEST] <safinaskar> and my player supports playing in both ways
[11:06:31 CEST] <safinaskar> so, is there saner solution? maybe player i need exists?
[11:20:48 CEST] <furq> safinaskar: apparently gstreamer supports that, idk if any players expose that functionality though
[11:21:02 CEST] <furq> https://gstreamer.freedesktop.org/documentation/tutorials/basic/playback-speed.html?gi-language=c
[11:22:13 CEST] <furq> it's not a trivial thing to do with inter-frame codecs so most players/libs don't bother trying
[11:22:54 CEST] <furq> ffmpeg will do it if you don't mind buffering the entire decoded video in memory, which you probably do
[11:25:19 CEST] <safinaskar> furq: thanks
[11:25:48 CEST] <safinaskar> furq: "inter-frame codecs" - i don't need support for all codecs. at least one codec will go (and i will convert my video to that codec)
[11:26:49 CEST] <safinaskar> furq: "ffmpeg will do it if you don't mind buffering the entire decoded video in memory" - you mean ffmpeg ability to reverse video? i need different thing. i need player, which can play in both ways. i. e. i want to be able to switch playing from forward to backward in any moment
[11:27:39 CEST] <furq> well i assume there's some way of getting mpv etc to do it, but it'd be using the reverse filter
[11:27:48 CEST] <furq> which buffers the whole clip
[11:29:15 CEST] <safinaskar> furq: gstreamer docs don't show code for vala language. this is bad
[11:30:24 CEST] <safinaskar> furq: "there's some way of getting mpv etc to do it" - what way? i read mpv man page and i don't see mentions of reverse playing
[11:31:00 CEST] <safinaskar> furq: let's assume for a moment that buffering whole clip is OK
[11:31:04 CEST] <safinaskar> furq: what can i do then?
[11:47:00 CEST] <durandal_1707> safinaskar: see wm4 mpv AGPL branch,  it have such support
[11:49:36 CEST] <safinaskar> durandal_1707: ok, i will see
[12:01:46 CEST] <safinaskar> durandal_1707: i could not find it
[12:08:37 CEST] <durandal_1707> https://github.com/mpv-player/mpv/pull/6781
[12:09:19 CEST] <safinaskar> durandal_1707: thanks
[12:09:23 CEST] <durandal_1707> he removed his repo though, he is too sensitive
[15:18:40 CEST] <safinaskar> durandal_1707: i finally was able to build the repo you send
[15:18:42 CEST] <safinaskar> durandal_1707: thanks
[15:18:52 CEST] <safinaskar> durandal_1707: now i am trying to understand how to use this feature
[15:25:09 CEST] <safinaskar> "commit 2b39a48448efb68fbe10d9042540c39923eea205. Implement backwards playback. You can bet there are shit tons of bugs. It's literally forcing square pegs into round holes"
[15:25:12 CEST] <safinaskar> from git
[16:38:31 CEST] <zerodefect> I'm playing an MP4 2160p24 encoded with HEVC using ffplay. How do I determine which codec was used for decode? I don't see anything obvious in ffplay output.
[16:38:55 CEST] <zerodefect> Stream #0:0(und): Video: hevc (Main) (hvc1 / 0x31637668), yuv420p(tv), 3840x2160, 2010 kb/s, 24 fps, 24 tbr, 24k tbn, 24 tbc (default)
[18:00:42 CEST] <Hello71> I think it's builtin unless you use -hwaccell
[18:00:45 CEST] <Hello71> s/ll/l/
[19:31:12 CEST] <Hackerpcs> how to specify multiple options for the writer on ffprobe? "-of csv=p=0=s=A" doesn't work
[19:42:29 CEST] <Hackerpcs> nvm, it's "-of csv=p=0:s=A"
[19:51:20 CEST] <fred1807> I streaming local mp4 files to a rtmp server
[19:51:39 CEST] <fred1807> but my machine is too slow, and video keeps hanging
[19:51:55 CEST] <fred1807> is it possible to ffmpeg buffer , a lot.. ?
[19:54:09 CEST] <DHE> if you're transcoding, sure
[20:01:23 CEST] <BtbN> In the most simple case, just stream the mp4 unmodified? It most likely is h264 + aac already.
[20:01:36 CEST] <BtbN> so just remux to flv, and stream to rtmp
[20:10:09 CEST] <fred1807> I am transcoding all files to h264 first..
[20:10:17 CEST] <fred1807> so there is not change in the streaming spec
[20:10:40 CEST] <BtbN> Do that in advance then and stream the results
[20:11:22 CEST] <fred1807> the movie files lib, is already all the  free space i have..
[20:11:30 CEST] <fred1807> but that would work...
[20:11:50 CEST] <BtbN> It's the most buffering you can possibly get.
[20:12:03 CEST] <fred1807> indeed
[20:12:12 CEST] <fred1807> I have 4gb of ram
[20:12:18 CEST] <fred1807> I see ffmpeg only using 512mb...
[20:12:35 CEST] <fred1807> can I make it use more ram , maybe?
[20:13:10 CEST] <BtbN> I wouldn't know how to setup output buffering on top of my head
[20:18:00 CEST] <fred1807> impossible to add a watermark without reencoding, right?
[20:22:35 CEST] <durandal_1707> yes, possible. but you need 1tb of ram
[20:24:01 CEST] <BtbN> And a killer connection to stream that uncompressed stuff?
[20:28:50 CEST] <fred1807> -crf 0   ?
[20:30:14 CEST] <fred1807> vcodec copy  makes it smooth like a breeze
[20:30:27 CEST] <fred1807> problema is that the client browser player breaks with the movie change
[20:30:27 CEST] <durandal_1707> why you need of ffmpeg to use more RAM?
[20:30:56 CEST] <BtbN> There isn't really any way to avoid that, the timestamps don't match up between the files
[20:31:18 CEST] <BtbN> How are you even playing rtmp in a browser? Still using flash?
[20:31:54 CEST] <fred1807> no... I am seding to restream.io
[20:31:58 CEST] <fred1807> and watching on twitch
[20:32:11 CEST] <fred1807> or sending directly to twitch
[20:32:36 CEST] <BtbN> You will need to send one continous stream then, or cut and restart between independend files
[20:59:14 CEST] <zerodefect> thanks @Hello71
[21:23:09 CEST] <brontosaurusrex> What would be a method to check if there is a significant difference in fields, before deinterlacing, which could auto-decide if double-deint makes sense or not (like should it use yadif 0 or 1)?
[21:25:54 CEST] <brontosaurusrex> I do have crude 'isInterlaced' script working, using 'idet' filter.
[21:26:20 CEST] <brontosaurusrex> But it needs to get significantly smarter to decide stuff like that.
[21:40:48 CEST] <Jook> any ffmpeg dev here?
[21:41:17 CEST] <DHE> just ask your question
[21:41:43 CEST] <Jook> DHE are you ffmpeg dev
[21:42:07 CEST] <pink_mist> Jook: why in the world do you need only an ffmpeg dev?!
[21:42:09 CEST] <DHE> irrelevant
[21:42:37 CEST] <Jook> okay: how come nobody can fix this? https://trac.ffmpeg.org/ticket/7912
[21:43:41 CEST] <DHE> because you failed to follow the rules for bug submission
[21:44:03 CEST] <Jook> dhe what do you mean
[21:56:57 CEST] <durandal_1707> devs are busy with real life issues
[23:44:37 CEST] <severs> Hi, I'm using ffmpeg to reencode an eac3 file at the same bit rate (1535k).  Then muxing back to mkv with mkvmerge.
[23:45:22 CEST] <severs> For some reason, the original audio skips every second or so (playing in Kodi with audio passthrough to HDMI)
[23:46:05 CEST] <severs> so, something ffmpeg does to the file makes the sync better.  So my question is:
[23:48:07 CEST] <severs> is there an option to make ffmpeg just copy the eac3? Other than -c:a copy, because that creates a bit-exact copy of the original (duh)
[23:51:02 CEST] <severs> I doubt I can tell the difference if I reencode, but was wondering if there's a way to copy the input audio, but use ffmpegs output format routines, in case that's the difference that makes the syncwork
[23:53:21 CEST] <BtbN> That's what -c copy does
[23:53:26 CEST] <BtbN> not reencode
[23:58:06 CEST] <severs> right, but the reencoded file works, while the original skips.  So I think there's something about the reencoded file that is "more correct" than the original
[23:58:36 CEST] <severs> was hoping to get there without actually encoding
[23:59:25 CEST] <severs> I guess I'll look at the 2 files to see if anything sticks out
[00:00:00 CEST] --- Sat Aug 10 2019