[Ffmpeg-devel-irc] ffmpeg.log.20180524

Fri May 25 03:05:01 EEST 2018

[01:01:26 CEST] <wfbarksdale> I do not need to support 10 bit color today, but I'm wondering how this looks at the AVFrame level since uint8_t is used to hold the data buffers for AVFrames
[01:02:50 CEST] <kepstin> 10bit and higher image data is stored in 16bit values, can be in either endianness.
[01:03:44 CEST] <kepstin> assuming native endian values, you could cast the data pointer to a uint16_t array, otherwise use appropriate endian-converting extraction functions.
[01:04:46 CEST] <wfbarksdale> gotchya
[01:10:57 CEST] <JEEB> wfbarksdale: most APIs deal with "set of byte"s anyways
[10:16:07 CEST] <Brian_> hi, i am trying to scale/animate an image in the center of a background video. I tried with zoompan but it doesnt keep the aspect ratio. Anything i can do?
[11:27:16 CEST] <tomtomb> Hi all, I got an ffprobe question.. is it possible to have the warnings show in json mode in a correct json syntax? (-print_format json -loglevel warning) would print something like "{ [mxf @ 000000000] broken or empty index }"... my json parser wouldn't read that..
[12:49:58 CEST] <th3_v0ice> Hi all. How is it possible that decoder timebase changes while decoding? I thought that this value was constant? Can anyone explain?
[12:55:18 CEST] <th3_v0ice> .
[14:38:09 CEST] <Freneticks> hey i have a weird problem with ffmpeg, i try to open many link to record stream, everythings is working, except after some time i got cannot resolv host
[14:38:58 CEST] <Freneticks> i can ping host, dig it, but ffmpeg just doesn't want to open it
[15:06:04 CEST] <kepstin> tomtomb: warnings should be printed to stderr, not stdout, so they don't get mixed with the json content
[16:12:35 CEST] <edgar_> Hey guys. Im currently experiencing with an raspberry pi 3 and ffmpeg to stream live to youtube. i managed to get a smooth nice live stream with streamcopy in h264. Is there a way to still use complex filters? Unfortunately filtering and streamcopy cannot be used together. Do you think there is a way for raspberry pi ?
[16:17:51 CEST] <edgar_> ... if im doing stuff without streamcopy, the fps is < 5 and 0,4xxx speed.
[17:25:47 CEST] <furq> edgar_: ffmpeg can use the pi's builtin hardware h264 decoder and encoder if you built it with --enable-mmal --enable-omx
[17:26:19 CEST] <furq> the quality isn't good at all but that's pretty much your only hope of getting it to run fast enough
[19:14:00 CEST] <wfbarksdale> Am I understanding line size correctly here?
[19:14:08 CEST] <wfbarksdale> +++++--
[19:14:10 CEST] Last message repeated 2 time(s).
[19:14:10 CEST] <wfbarksdale> width = 5(height = 3
[19:14:12 CEST] <wfbarksdale> linesize = 7
[19:15:04 CEST] <wfbarksdale> so the '+' represents a useable pixel and the '-' is padding
[19:26:19 CEST] <wfbarksdale> it appears there may also be extra lines as well? I guess you never really need info about these extra lines because you are always stopping short?
[19:44:01 CEST] <wfbarksdale> another oddity, I took a video using iphone in portrait, so was expecting to see ffmpeg provide side_data for each AVFrame of video to know how to rotate it, however i don't see this side data in my test :/ do i need to pass some sort of flag to make sure i get that data?
[19:45:12 CEST] <Mavrik> Yes, you're understanding line size (also called stride) correctly
[19:45:24 CEST] <Mavrik> and yeah, you can have extra lines at the end but that shouldn't really affect you
[19:47:59 CEST] <saml_> anyone has experience with running ffmpeg with http?  I want ffmpeg to directly upload the result to S3
[19:48:04 CEST] <saml_> S3 is Amazon storage
[19:49:12 CEST] <Mavrik> I guess as long as you use an output format that doesn't require seeking it should work.
[19:51:02 CEST] <wfbarksdale> saml_ don't you just want to use `aws s3 cp` in a script to copy the resulting video? or are you trying to do some sort of fancy streaming thing
[19:55:00 CEST] <saml_> i'm trying to do fancy streaming :P
[20:03:13 CEST] <ChocolateArmpits> try mpegts it's fit for that kind of situation
[20:33:46 CEST] <xjuan_> hello guys, I am trying to stream my desktop to a virtual video device
[20:33:57 CEST] <xjuan_> sudo ffmpeg -f x11grab -r 30 -s 1920x1080 -i :1.0+0,0 -vcodec rawvideo -pix_fmt yuv420p -threads 0 -f v4l2 /dev/video0
[20:34:21 CEST] <xjuan_> but I get an error "[v4l2 @ 0x5624fd4e8f80] ioctl(VIDIOC_G_FMT): Invalid argument"
[20:34:29 CEST] <xjuan_> https://pastebin.com/KR4dmcMZ
[20:37:46 CEST] <saml_> what's a virtual video device?
[20:40:04 CEST] <xjuan_> a virtual v4l2 device created with the loopback module
[20:40:19 CEST] <xjuan_> sudo modprobe v4l2loopback
[20:40:36 CEST] <xjuan_> that should create a dummy /dev/video0
[20:40:51 CEST] <xjuan_> which in theory you can then send any kind of video to it
[20:41:09 CEST] <xjuan_> for example a desktop screencast
[20:41:30 CEST] <saml_> xjuan_, did you load the module?
[20:41:52 CEST] <xjuan_> saml_, yeah
[20:42:25 CEST] <xjuan_> lsmod | grep v4l2loopback
[20:42:25 CEST] <xjuan_> v4l2loopback           40960  0
[20:42:25 CEST] <xjuan_> videodev              204800  1 v4l2loopback
[20:43:04 CEST] <saml_> what about ls /dev/video* ?
[20:43:10 CEST] <saml_> video0 is the right device?
[20:43:37 CEST] <xjuan_> yeah, its the only one
[20:44:09 CEST] <xjuan_> v4l2-ctl  --list-device --verbose
[20:44:09 CEST] <xjuan_> Dummy video device (0x0000) (platform:v4l2loopback-000):
[20:44:09 CEST] <xjuan_> 	/dev/video0
[20:44:09 CEST] <xjuan_> VIDIOC_QUERYCAP: ok
[20:45:49 CEST] <saml_> v4l2-ctl -d /dev/video0 -l
[20:46:29 CEST] <xjuan_> v4l2-ctl -d /dev/video0 -l
[20:46:29 CEST] <xjuan_> User Controls
[20:46:29 CEST] <xjuan_>                     keep_format 0x0098f900 (bool)   : default=0 value=0
[20:46:29 CEST] <xjuan_>               sustain_framerate 0x0098f901 (bool)   : default=0 value=0
[20:46:29 CEST] <xjuan_>                         timeout 0x0098f902 (int)    : min=0 max=100000 step=1 default=0 value=0
[20:46:29 CEST] <xjuan_>                timeout_image_io 0x0098f903 (bool)   : default=0 value=0
[20:48:30 CEST] <saml_> xjuan_, maybe try   sudo ffmpeg -re -f x11grab ....   (add -re)
[20:48:53 CEST] <saml_> and don't specify -r 30
[20:49:33 CEST] <saml_> and possibly drop -s 1920x1080  as well.  or move that -s option after -i
[20:49:36 CEST] <xjuan_> same error
[20:49:59 CEST] <xjuan_> looks like ffmpeg is trying some ioctl that is not supported by the loopback device
[20:53:22 CEST] <saml_> https://www.ffmpeg.org/ffmpeg-devices.html#video4linux2_002c-v4l2  not sure if ffmpeg supports video4linux as output
[20:53:28 CEST] <saml_> it reads like it's an input only
[20:56:18 CEST] <saml_> ffmpeg -f x11grab -framerate 15 -video_size 1280x720 -i :0.0 -f v4l2 /dev/video0
[20:56:26 CEST] <saml_> https://askubuntu.com/questions/881305/is-there-any-way-ffmpeg-send-video-to-dev-video0-on-ubuntu
[20:56:36 CEST] <saml_> looks like as output would work.. i don't know
[20:58:37 CEST] <xjuan_> saml_, yeah thats the first post I found and where I took the example
[20:58:44 CEST] <xjuan_> does it work for you?
[20:59:01 CEST] <xjuan_> maybe there is something wrong with my module
[21:05:01 CEST] <saml_> it doesn't work for me xjuan_
[21:06:42 CEST] <xjuan_> saml_, ohh well, thanks for your help
[21:11:45 CEST] <saml_> hrm i don't even have v4l2loopback
[21:12:25 CEST] <xjuan_> ohh, I guess that explains why it does not work for you
[21:12:26 CEST] <xjuan_> hehe
[21:12:50 CEST] <saml_> xjuan_, just curious, did you try to use a normal video file as input. and the loopback as output?
[21:13:08 CEST] <saml_> ffmpeg -re -i input.mp4 -map 0:v -f v4l2 /dev/video0    # as the webpage says
[21:13:23 CEST] <saml_> to narrow down the problem isn't x11grab  -i :0.0
[21:22:37 CEST] <xjuan_> saml_, yeah that does not work
[21:22:44 CEST] <xjuan_> also x11grab to a file does
[21:29:06 CEST] <saml_> https://github.com/umlaeute/v4l2loopback/wiki/Ffmpeg   weird this should work  xjuan_
[21:29:14 CEST] <saml_> what's your ffmpeg version?
[21:29:28 CEST] <saml_>  .... If you have an older FFmpeg version, you can rely on GStreamer: t
[21:30:12 CEST] <saml_> try with 4.0   (static build here https://johnvansickle.com/ffmpeg/)
[21:32:08 CEST] <furq> oh hey the static builds are back
[21:34:44 CEST] <edgar_> if i use "-preset" on ffmpeg, it fails and say "Unrecognized option 'preset'.
[21:34:44 CEST] <edgar_> Error splitting the argument list: Option not found
[21:34:44 CEST] <edgar_> ". is my installation fucked up?
[21:35:31 CEST] <JEEB> preset is a component specific option
[21:35:41 CEST] <JEEB> if the encoder or whatever you're using doesn't have that AVOption
[21:35:49 CEST] <JEEB> then it will tell you that such an option does not exist
[21:36:06 CEST] <JEEB> -h encoder=libx264 for example gives you what is available for libx264, IIRC
[21:45:08 CEST] <xjuan_> saml_, ffmpeg version 3.4.2-2+b1
[21:45:26 CEST] <edgar_> JEEB, thank you
[21:50:37 CEST] <xjuan_> saml_, just tried with ffmpeg version 4.0-2 from debian/experimental
[21:50:40 CEST] <xjuan_> same error
[21:56:06 CEST] <saml_> meh
[21:56:11 CEST] <saml_> out of idea
[22:20:43 CEST] <mifritscher1> moin
[22:22:07 CEST] <mifritscher1> i'm using the library directly to grab frames from a rtsp camera wich is connected via wlan. Is there an option that it uses a buffer to "smooth" the duration between getting 2 frames, at the cost of an higher delay? setting max_delay doesn't seem to help for me...
[22:29:46 CEST] <mifritscher1> on my wlan, i get sometimes the sitation that 300 ms long the computer gets no packet, and then all in a row. This could be mitigitated by having a buffer of 500ms
[22:33:11 CEST] <ChocolateArmpits> mifritscher1, did you try analyzeduration or probesize ?
[22:56:55 CEST] <mifritscher> sorry, got disconnected because of empty battery :-(
[22:58:22 CEST] <blurry_light> if I have a video file I backed up with multiple audio tracks for different languages, how do I make one video file with one single audio track, preserving quality for both video and audio?
[22:58:46 CEST] <blurry_light> my approach was to make a nosound version of the video alone and now I want to extract the one audio track I want and merge it with the soundless video
[22:59:12 CEST] <blurry_light> the audio stream is "Stream #0:5(eng): Audio: dts (DTS), 48000 Hz, 5.1(side), fltp, 1536 kb/s"
[22:59:20 CEST] <blurry_light> what would be the best way to extract this losslesly?
[22:59:25 CEST] <blurry_light> losslessly*
[23:01:17 CEST] <furq> -i foo -c copy -map 0:5 bar.dts
[23:01:34 CEST] <blurry_light> ok, so .dts is an audio format/container?
[23:01:44 CEST] <furq> or just -i soundless -i source -map 0:v -map 1:5 -c copy out.mkv
[23:01:51 CEST] <blurry_light> O.O
[23:01:58 CEST] <blurry_light> that's some insane wizardry there
[23:01:59 CEST] <blurry_light> hold on
[23:03:38 CEST] <blurry_light> oh wow, that's clever
[23:20:48 CEST] <marcurling> Hello pals, what's the use of libpostproc (once ffmpeg compiled) please?
[23:25:13 CEST] <furq> !filter pp @marcurling
[23:25:13 CEST] <nfobot> marcurling: http://ffmpeg.org/ffmpeg-filters.html#pp
[23:25:36 CEST] <furq> i assume it's in a separate lib because it's gpl
[23:29:51 CEST] Action: marcurling deeply thanks furq ;)
[00:00:00 CEST] --- Fri May 25 2018