[Ffmpeg-devel-irc] ffmpeg.log.20191013

[burek]

[03:20:59 CEST] <sagax> tbn/tbc what it's?
[03:21:58 CEST] <sagax> i just convert video `webm` to `ogg` without any options, and in result `ogg` have low quality then `webm`
[03:22:18 CEST] <sagax> and i see that tbn and tbc options have different
[03:23:50 CEST] <c_14> ogg defaults to theora afaik, it's going to be pretty bad (unless given sufficient bitrate)
[03:24:04 CEST] <furq> tbn and tbc are just timebase values
[03:24:06 CEST] <furq> that has nothing to do with quality
[03:24:36 CEST] <furq> also yeah there's really not any need to use theora any more
[03:25:53 CEST] <c_14> The first and most important question is probably why are you converting to ogg in the first place?
[03:27:14 CEST] <sagax> i just want very light format for video
[03:27:34 CEST] <sagax> when video should be play on low cpu
[03:27:34 CEST] <c_14> what's wrong with the original webm?
[03:27:39 CEST] <sagax> play in browser
[03:28:03 CEST] <sagax> webm - load cpu, i look about lighten format
[03:29:04 CEST] <sagax> maybe video file would be large size but i need that video should be less load cpu
[03:30:27 CEST] <c_14> If you want to play the video in a browser, you probably want H.264 in mp4. I believe most browsers should support that these days and offer hardware accelleration where available
[03:31:00 CEST] <furq> doesn't ffvp9 decode faster than ffh264
[03:31:24 CEST] <furq> i guess there's more widespread h264 hwdec but vp9 isn't really slow
[03:31:52 CEST] <sagax> c_14: i can't wait xD
[03:32:47 CEST] <c_14> furq: I think so, yeah. But if you want hwaccell you're mostly stuck with h264
[03:33:41 CEST] <sagax> hm, i will try
[03:33:42 CEST] <sagax> thanks
[03:34:03 CEST] <furq> are you actually having trouble decoding vp9
[03:34:04 CEST] <sagax> check hwaccell, ok
[03:36:34 CEST] <sagax> uff, in test - ogg fastet than webm
[03:36:41 CEST] <sagax> but quality low
[03:41:57 CEST] <furq> it defaults to like 200kbps if you didn't set a bitrate
[03:41:59 CEST] <furq> try -q:v 8 i guess
[03:42:10 CEST] <furq> 0 worst 10 best quality
[03:46:33 CEST] <lordarkmemo> hi
[03:47:14 CEST] <lordarkmemo> im streaming a video using -f flv rtmp://server.  But, when the rtmp server (nginx) stop, the ffmpeg hangs forever.  How i detect the lose connection with server using a ffmpeg flag?
[03:52:12 CEST] <sagax> furq: maybe, thanks, i will try -q:v 0
[03:52:24 CEST] <sagax> before i don't set -q:v option
[03:53:34 CEST] <another> remeber that 0 is worst quality
[03:53:55 CEST] <another> also: i don't think theora is widely supported in browsers
[03:55:20 CEST] <another> as c_14 said, if you want low cpu-usage your best guess is to use something hw accelerated on most modern systems
[03:55:55 CEST] <Diag> question, has anyone ran ffmpeg on the extremely unpopular xbox360 linux
[03:57:27 CEST] <furq> firefox and all the chrome variants play theora
[03:57:31 CEST] <furq> no safari or old IE though
[04:00:56 CEST] <sagax> i try again convert to ogg, and after will try convert to mp4
[04:01:12 CEST] <sagax> all ok - i use mozilla and chrome
[04:09:53 CEST] <sagax> hm, i set -q:v 0 but when in progress i see `q=29.0`
[04:10:05 CEST] <sagax> it's when convert webm to mp4
[04:11:21 CEST] <another> https://trac.ffmpeg.org/wiki/Encode/H.264
[04:14:12 CEST] <sagax> thanks
[04:15:06 CEST] <sagax> uff, how resize with save video and audio quality?
[04:16:05 CEST] <sagax> i found scaling
[04:16:58 CEST] <Diag> what do you mean by save video and audio quality
[04:18:02 CEST] <sagax> some like  -q:a same -q:v same
[04:18:14 CEST] <sagax> just not change any other format
[04:18:31 CEST] <sagax> and not change options about quality as default options
[04:20:24 CEST] <sagax> i found -c copy
[04:20:27 CEST] <sagax> will try
[04:23:21 CEST] <Diag> Does the constant quality value even get embedded into the h264 header?
[04:25:16 CEST] <sagax> i think no, or just don't understand
[04:25:55 CEST] <sagax> now i change -acodec and -vcodec and convert to webm with small scale
[04:26:19 CEST] <sagax> webm -> webm (scale/2)
[04:59:06 CEST] <lordarkmemo> im streaming a video using -f flv rtmp://server.  But, when the rtmp server (nginx) stop, the ffmpeg hangs forever.  How i detect the lose connection with server using a ffmpeg flag?
[04:59:10 CEST] <lordarkmemo> any help please
[05:00:48 CEST] <Diag> lordarkmemo: https://lists.ffmpeg.org/pipermail/ffmpeg-user/2018-March/039108.html
[05:00:51 CEST] <Diag> is what youre looking for i believe
[05:01:05 CEST] <Diag> whoops sorry misread the page
[05:01:18 CEST] <Diag> im retarded
[05:01:42 CEST] <Diag> Actually no, it says -stimeout should work 0.o
[05:05:10 CEST] <lordarkmemo> Diag: is a weird behavior, when i stop the nginx-rtmp server, the ffmpeg dont stop, it keeps hanging forever.
[05:05:27 CEST] <Diag> Even when you set the -stimeout flag?
[05:07:56 CEST] <lordarkmemo>  yes.  The funny thing is this.  When i install my nginx server on my local machine, every time i stop the (nginx), the ffmpeg streaming stop. But when i stop the nginx server on my AWS machine (remote), the ffmpeg hangs.  Is like ffmpeg dont detect the nginx kill signal.
[05:08:56 CEST] <Diag> worst case scenario you could always make a cron job or something that pings the server every 15 seconds to see if its alive, and have it pkill ffmpeg if not
[05:12:18 CEST] <lordarkmemo> Diag: this setting apply to -f rtmp://.. streaming?.  reconnect_streamed
[07:30:18 CEST] <dominiques> hello everyone, if can anyone help i will be glad ---> https://stackoverflow.com/questions/58360848/ffmpeg-udp-recording-every-hour
[07:30:41 CEST] <dominiques> thanks for your helping !
[07:36:55 CEST] <ponyrider> dominiques: couldnt you just add ffmpeg -ss 9:00:00 -to 10:00:00 -i udp:// ....
[07:47:21 CEST] <dominiques> will be precised ? also ?
[07:48:11 CEST] <dominiques> ffmpeg -ss 9:00:00:000 -to 10:00:00:000 -i udp://239.0.0.1:1234 -vcodec copy -acodec copy -f mpegts "output.ts"   it is possible use this way ?
[07:54:21 CEST] <ponyrider> dominiques: if you want miliseconds then you need 10:00:00.000
[07:54:34 CEST] <ponyrider> but how precise do you need it to be?
[07:54:41 CEST] <dominiques> as possible
[07:55:18 CEST] <dominiques> as much as possible
[07:57:13 CEST] <ponyrider> but your cutting every hour.. why worry about a microsecond?
[07:58:26 CEST] <ponyrider> because you are just copying the video without reencoding, its going to cut it at the nearest keyframe anyway, so ..
[22:24:09 CEST] <anticw> is this channel appropriate for api-level noob questions?   specifically i want to know about splitting ".mp4 files" at i-frame boundaries ... the goal is that each 'subfile' of a stream should be nicely self-contained
[22:26:04 CEST] <anticw> i'm also curious as to how indexing of these works (in some ideal sense), that is, is there a header with index/seek information or is it distributed throught the entire file and players use a heuristic seek to determine frame boundaries?
[22:39:34 CEST] <JEEB> anticw: with mp4 specifically you've either got a single index for a track (in FFmpeg speak AVStream), or you have multiple fragments and each of them has their own index (there's also the possibility of there being a full-on seeking index at the end)
[23:06:34 CEST] <DanielTheKitsune> how do I make ffmpeg produce a sequential continous .mp4 stream that can be read even if the encoding/building process gets interrupted (blackout, reading while unfinished, system crash)?
[23:07:49 CEST] <DanielTheKitsune> say, I connect a webcam that serves as a cheap security camera, and I want to know why the system randomly gets shut down, so I can see if someone comes to disconnect it or if it's actually a blackout, or any other error
[23:08:30 CEST] <DanielTheKitsune> the software itself can't tell if it's a blackout or if the power strip gets powered off or disconnected
[23:17:07 CEST] <JEEB> DanielTheKitsune: either use something streaming (without a global index) or utilize movie fragments with a short enough fragment duration
[23:17:59 CEST] <DanielTheKitsune> syntax?
[23:18:13 CEST] <DanielTheKitsune> can't use streaming to the outside
[23:18:22 CEST] <DanielTheKitsune> the thing has to be stored on said computer
[23:18:46 CEST] <JEEB> no, I mean a streaming container (as opposed to mp4, which without movie fragments has a single index)
[23:18:48 CEST] <DanielTheKitsune> and I'm willing to lose some few seconds regarding cache (Linux appears to write fairly quickly, it doesn't delay a lot)
[23:19:15 CEST] <DanielTheKitsune> JEEB: ok
[23:19:19 CEST] <JEEB> also do note that not all applications that read "normal" mp4 read fragmented mp4
[23:19:23 CEST] <DanielTheKitsune> which container do you suggest?
[23:19:24 CEST] <JEEB> FFmpeg can
[23:19:30 CEST] <DanielTheKitsune> I'm gonna use ffmpeg or vlc
[23:19:45 CEST] <DanielTheKitsune> so any non-standard hiccup that is not fully broken will be read
[23:19:50 CEST] <JEEB> I would probably go with something like either matroska or mpeg-ts
[23:19:55 CEST] <DanielTheKitsune> ok
[23:20:05 CEST] <JEEB> so .mkv or .ts
[23:20:16 CEST] <JEEB> both of those should be readable even if you kill -9 the process
[23:20:28 CEST] <DanielTheKitsune> and I also need a vcodec that doesn't die
[23:20:31 CEST] <JEEB> testing it should be quick enough :)
[23:20:34 CEST] <DanielTheKitsune> what do you suggest?
[23:20:48 CEST] <JEEB> A->B should work OK since the initialization data should be written at the beginning?
[23:20:58 CEST] <JEEB> so it would be on the layer of "what got written to the FS"
[23:21:03 CEST] <DanielTheKitsune> yap
[23:22:02 CEST] <DanielTheKitsune> ok, I'll test as soon as the current job finishes
[00:00:00 CEST] --- Mon Oct 14 2019