[Ffmpeg-devel-irc] ffmpeg.log.20170105

burek burek021 at gmail.com
Fri Jan 6 03:05:01 EET 2017

[00:12:51 CET] <furq> if you have the same libdl.so as your target then it should work
[00:12:57 CET] <furq> otherwise you're screwed
[00:17:29 CET] <mbarisa_> should be but it doesn't work
[00:17:37 CET] <mbarisa_> it cannot find ldl
[00:52:00 CET] <_Vi> Where is the exhaustive list of FFmpeg formula variables like "iw" or "ih" documented? Expected to find it on https://ffmpeg.org/ffmpeg-utils.html#Expression-Evaluation , but there only functions.
[00:52:26 CET] <furq> ih, iw etc are filter-specific
[00:53:06 CET] <_Vi> For example, is there frame number (or time)?
[01:02:53 CET] <llogan> depends on the filter
[02:32:45 CET] <Phi_> hm
[04:21:41 CET] <|zork|> what is best lossy audio codec right now?
[04:24:34 CET] <c_14> opus or aac depending on your use-case
[04:25:06 CET] <|zork|> what is better opus or aac  for  music
[04:25:20 CET] <|zork|> what is better opus or aac  for  5.1 movies
[04:26:14 CET] <c_14> If your player supports both, at decent bitrates you won't notice a difference
[04:26:36 CET] <|zork|> does ffmpeg support aac?
[04:26:41 CET] <c_14> yes
[04:26:48 CET] <|zork|> which one
[04:38:32 CET] <c_14> the encoder is called aac
[04:38:36 CET] <c_14> It's internal
[07:10:37 CET] <TD-Linux> opus is basically always better, unless you need compatibility with old hw
[09:17:00 CET] <Ghost4> Anyone for hire to help with some lines of code in a bashscript, regarding linux encode with a few different settings
[09:17:49 CET] <Ghost4> + if there is someway to get automated crops aswell
[09:21:54 CET] <Ghost4> Reply to ghost1 if someone are able to help with this thx
[09:50:51 CET] <vinay_> hello @everyone
[09:50:52 CET] <vinay_> i am noob to ffmpeg, i have created ffserver which is running fine but how can i stream mobile back camera to that server ???
[10:01:19 CET] <thebombzen> ghost1: -vf autocrop
[10:01:25 CET] <thebombzen> sorry my bad
[10:01:27 CET] <thebombzen> -vf cropdetect
[10:01:50 CET] <thebombzen> -vf cropdetect spits out the (detected) best crop filter
[10:01:58 CET] <thebombzen> but you need to parse it and feed it back into another command
[12:20:31 CET] <ghost1> thebombzen: yes i know this.. but there is some other features i really need help with
[13:10:45 CET] <vinay_> need help
[13:11:19 CET] <klaxa> ok
[13:42:45 CET] <wouter> hi -- can anyone shed some light on why https://trac.ffmpeg.org/wiki/Encode/AAC suggests that libfdk_aac is of "higher" quality than the builtin aac encoder?
[13:45:29 CET] <wouter> i.e., how is it better (beyond speed which doesn't matter for my purposes), and what would I lose if I chose to not recompile my ffmpeg (which doesn't have it compiled in)
[13:47:14 CET] <vinay_> klaxa: i am noob to ffmpeg, i have created ffserver which is running fine but how can i stream mobile back camera to that server ???
[13:54:07 CET] <kerio> wouter: quality at the same bitrate
[16:06:21 CET] <bencc1> can I use ffmpeg to create a virtual webcam on Windows?
[16:06:27 CET] <bencc1> if not, is there any other tool?
[16:07:09 CET] <klaxa> just for the record: afaik ffserver has been dropped in july 2016 with no replacement...
[16:07:39 CET] <durandal_170> nope ffserver still lives
[16:09:02 CET] <klaxa> oh?
[16:09:12 CET] <klaxa> what about the news of dropping it then?
[16:12:55 CET] <klaxa> i should read the ML before making statements :)
[16:16:16 CET] <k_sze> Out of curiosity, when building ffmpeg from source, why does --enable-gray make color slower?
[16:35:34 CET] <Guest172> how can i set the framerate of the mpegts using ffmpeg while recording hls stream ? i tried with the -r 10 option but without success, is it even possible for the mpegts ?
[17:03:29 CET] <DHE> have you tried -framerate ?
[17:18:53 CET] <Guest172> yes i tried, the result is the same, hmmm it seems i will have to rely on the nal header
[17:18:59 CET] <Guest172> ffmpeg -y \
[17:19:01 CET] <Guest172>   -i live.h264 \
[17:19:03 CET] <Guest172>   -framerate 7 \
[17:19:05 CET] <Guest172>   -f s16le -i /dev/zero -r:a 48000 -ac 2 \
[17:19:07 CET] <Guest172>   -c:v copy \
[17:19:09 CET] <Guest172>   -c:a aac -b:a 128k  \
[17:19:11 CET] <Guest172>   -map 0:0 -map 1:0 \
[17:19:13 CET] <Guest172>   -f segment \
[17:19:15 CET] <Guest172>   -segment_time 8 \
[17:19:17 CET] <Guest172>   -segment_format mpegts \
[17:19:19 CET] <Guest172>   -segment_list "$base/live.m3u8" \
[17:19:21 CET] <Guest172>   -segment_list_size 720 \
[17:19:23 CET] <Guest172>   -segment_list_flags live \
[17:19:25 CET] <Guest172>   -segment_list_type m3u8 \
[17:19:27 CET] <Guest172>   "%08d.ts" < /dev/null
[18:03:21 CET] <phillipk> I'm interested in the kinds of projects people are working on--please share.  My current thing is creating videos from data collected during live webinars on an old system I built.  The result is as if we recorded the screen live--but, for many reasons, we do not do that--instead I collect the data (like what is on screen) and I do record the audio... it all gets sewn together into the final output video for youtube.  Anyway, pleas
[18:10:41 CET] <gwohl> I am a bit confused about which lossless mezzanine codec I should be using -- FFV1 or ffvhuff? I'll be using these codecs to both process and archive high resolution (8k) video.
[18:11:16 CET] <kerio> are you going to use anything other than ffmpeg?
[18:11:24 CET] <kerio> ffv1 is a standard
[18:12:04 CET] <kerio> you could consider lossless h264
[18:15:52 CET] <gwohl> kerio will not be using anything other than ffmpeg. are there speed/efficiency gains using lossless h264 over ffv1?
[18:16:43 CET] <kerio> gwohl: idk actually
[18:16:52 CET] <kerio> ffvhuff is basically free
[18:16:59 CET] <kerio> but it's also bigger than ffv1
[18:22:33 CET] <durandal_170> utvideo too
[18:32:22 CET] <Guest52579> I'm having a problem with the drawtext video filter. I can get it to run everything using an 'expr' but if I want an int output using eif, it says it doesn't recognize the command. Do I need to compile an extra library for eif to work? that seems like a weird requirement
[18:41:56 CET] <Xstasy> Will ffmpeg report data errors from a raw ts stream if i go verbose?
[19:17:42 CET] <DrManhattan> if I am using ffdshow in Windoze, does the video card you are using matter (AMD vs Nvidia) when it comes to decoding quality? I've noticed a LOT more artifacts in the videos I watch with an AMD card vs my older Nvidia
[19:22:24 CET] <BtbN> no
[19:29:55 CET] <DrManhattan> curious - I wonder what causes such crazy compression artifacts when viewing videos...
[19:32:40 CET] <phillipk> are the source videos odd pixel dimensions?  are they already compressed?
[19:38:22 CET] <__raven__> hi
[19:39:52 CET] <__raven__> how to cut a video with ss and t while regenerating the missing keyframes? in that case when i split a x264 with gop 250 i get some seconds audio only and video starts later
[19:42:49 CET] <DrManhattan> phillipk, 1920x1080 and barely compressed - I think this may be an issue with AMD drivers and directshow to be honest
[19:43:14 CET] <DrManhattan> I'm going to try out an nvidia gtx960 and see if there's any difference
[19:49:49 CET] <phillipk> so the same output file plays okay in other players/cards?
[19:57:05 CET] <DrManhattan> I'll let you know in a few hours phillipk
[20:20:02 CET] <BotoX> Hello, I am looking through the FFMPEG sourcecode and find myself in a very confused state.
[20:20:32 CET] <BotoX> What I'd like to achive is to set SO_LINGER on tcp sockets in the SIGINT handler.
[20:21:05 CET] <BotoX> But I have no idea where to find all the URLProtocol's from ffmpeg_cleanup
[20:22:22 CET] <BotoX> when I try to backtrace where URLProtocol is used I end up with this URLProtocol <- URLContext <- AVIODirContext DEAD_END.
[20:26:01 CET] <BotoX> Or what I'd actually want to achieve in the bigger picture is: when ffmpeg receives SIGINT it should "murder" the tcp socket so the server will know immediately that the client died
[20:27:12 CET] <BotoX> setting SO_LINGER on every socket to on and linger time to 0 achieves that but also looses data when ffmpeg exits cleanly
[20:27:34 CET] <BotoX> so I was thinking only settings linger in the SIGINT exit handler would be a clever idea
[20:40:49 CET] <BotoX> alright *(void **)0 = 1; is always helpful
[20:41:00 CET] <kerio> :|
[20:41:08 CET] <BotoX> and bt'ing with gdb
[20:41:31 CET] <DHE> I'm a fan of abort();
[00:00:00 CET] --- Fri Jan  6 2017

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