[Ffmpeg-devel-irc] ffmpeg.log.20150828

burek burek021 at gmail.com
Sat Aug 29 02:05:01 CEST 2015

[00:25:38 CEST] <CraziFuzzy> DHE, thanks for the help.  I think I stumbled upon a much simpler way to do things.  instead of having ffmpeg write to a file, I can probably have ffmpeg pipe its output to a very simple program that writes x of it's stdin bytes to a file, then moves its pointer to the beginning and continues writing.
[03:30:19 CEST] <k_sze> If, after decoding a frame, I perform a sws_scale to convert it to another pixel format, what's the best way to copy the "metadata" from the source AVFrame to the destination AVFrame?
[03:30:28 CEST] <k_sze> Does ffmpeg have a function for that?
[03:32:19 CEST] <k_sze> (because after sws_scale from a srcFrame to a dstFrame, dstFrame only has pixel data, but no metadata such as the pts/dts of dst, and I want to preserve those.
[03:33:47 CEST] <k_sze> s/pts\/dts of dst/pts\/dts of srcFrame/
[03:35:20 CEST] <k_sze> I probably could copy manually, but it would be nice if ffmpeg has a function that copies metadata so I don't miss anything meaningful.
[09:19:10 CEST] <k_sze> So I'm reading this: http://ffmpeg.org/doxygen/2.5/group__lavc__decoding.html#ga99ee61b6dcffb7817a275d39da58cc74
[09:19:43 CEST] <k_sze> I notice it says: "When AVCodecContext.refcounted_frames is set to 0, the returned reference belongs to the decoder and is valid only *until the next call to this function or until closing or flushing the decoder*."
[09:20:06 CEST] <k_sze> What does it really mean? "until the next call to this function or until closing or flushing the decoder"???
[09:20:16 CEST] <k_sze> Whichever happens last for the current packet?
[09:36:12 CEST] <jules> hey, is there a way to get the current decoder frame rate / bit rate from the c API?
[10:39:50 CEST] <thecoolguy> if i seperate outputs by \
[10:40:01 CEST] <thecoolguy> is there 2 sperate encoding operations happening ?
[11:13:57 CEST] <thecoolguy> fflogger http://pastie.org/private/zgqiztveeaulpjyo8ar1xa
[11:16:47 CEST] <thecoolguy> what am i doing wrong?
[11:48:43 CEST] <fAmp> HI there,
[11:48:48 CEST] <fAmp> i have a question
[11:49:08 CEST] <fAmp> if i try to ps -aux | grep ffmpeg, the process is show 0.00 cpu usage
[11:49:52 CEST] <fAmp> i want to monitor this application, is there anyone that have any ide how to get that information working but just simple commands ?
[11:51:01 CEST] <a_functionalist> hello, I have one question. When opening a file with the -re option and pipe output, then ffmpeg doesn't wait until the receiver begins to read in data. without the -re option, ffmpeg does wait though. does anyone know how to get it to wait even with -re enabled?
[12:03:46 CEST] Last message repeated 1 time(s).
[12:03:46 CEST] <a_functionalist> (sorry for possible double post, was disconnected)
[13:55:21 CEST] <a_functionalist> hello can someone confirm that you set the blocksize option of an output pipe like this? pipe:1?blocksize=256
[13:55:35 CEST] <a_functionalist> the reason why i ask is, because blocksixxxxx=256 works as well.
[13:55:52 CEST] <a_functionalist> with it works I mean that ffmpeg won't show an error like: invalid option
[13:58:02 CEST] <teddythetwig> Hey yall, anyone here on UTC +2:00?
[16:45:08 CEST] <NapoleonWils0n> hi guys
[16:45:31 CEST] <NapoleonWils0n> just tring to use ffplay but get an error about SDL_AUDIODRIVER
[16:45:57 CEST] <NapoleonWils0n> im tying to use alsa audio, tried export SDL_AUDIODRIVER=alsa and export AUDIODEV=hw:1,0
[19:02:15 CEST] <DrBenway> i've trancoded a file using libavformat and the output file plays in vlc but not in windows media player
[19:02:26 CEST] <DrBenway> is there soemthing that i can do to get errors from the file?
[19:03:28 CEST] <DrBenway> basically i want to diagnose what went wrong with my mp4
[19:09:42 CEST] <FlorianBd> DrBenway: that would not really be ffmpeg's concern, the only thing you can do IMO is to use ffprobe to see exactly which format/codecs this file is using
[19:10:10 CEST] <DrBenway> any specific flags to ffprobe?
[19:10:45 CEST] <FlorianBd> https://www.ffmpeg.org/ffprobe.html
[19:18:30 CEST] <DrBenway> yeah i can read, my point is that there're a lot of flags and maybe some of them are better for debugging in my tyope of situation
[19:18:44 CEST] <c_14> DrBenway: you probably won't need any, maybe -show_format
[19:19:10 CEST] <llogan> -show_streams probably too
[19:19:43 CEST] <DrBenway> k
[19:37:43 CEST] <frenda> Is x265 supported by ffmpeg?
[19:38:08 CEST] <llogan> yes
[19:38:09 CEST] <frenda> Can I replace libx264 with libx265 here: https://trac.ffmpeg.org/wiki/Capture/Desktop ?
[19:38:22 CEST] <llogan> yes, if your build supports it
[19:39:04 CEST] <llogan> and the crf values will probably be different
[19:39:58 CEST] <llogan> any maybe presets/tunes too
[19:54:09 CEST] <frenda> How can I check is it supported otr not by my build? I've installed it via package manager ion fedora
[19:54:12 CEST] <frenda> in*
[19:54:21 CEST] <frenda> or*
[19:56:56 CEST] <c_14> ffmpeg -encoders
[19:59:22 CEST] <frenda> Yoohoo
[19:59:26 CEST] <frenda> V..... libx265              libx265 H.265 / HEVC (codec hevc)
[19:59:53 CEST] <frenda> Now, where I should I add lib x265 in this command:
[19:59:57 CEST] <frenda> `ffmpeg -video_size 1920x1080 -framerate 25 -f x11grab -i :0.0+100,200 output.mp4`
[20:00:07 CEST] <c_14> -c:v libx264 before output.mp4
[20:00:17 CEST] <JEEB> or more exactly, after -i
[20:00:22 CEST] <JEEB> and before the output
[20:01:14 CEST] <frenda> tnx
[20:05:46 CEST] <frenda> Stream #0:0 -> #0:0 (rawvideo (native) -> hevc (libx265))
[20:05:47 CEST] <frenda> Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height
[20:06:28 CEST] <c_14> There's usually another error hidden somewhere up
[20:08:39 CEST] <frenda> c_14: yeah: 4:2:2 and 4:4:4 support is not fully defined for HEVC yet. Set -strict experimental to encode anyway.
[20:08:44 CEST] <frenda> it's one line error
[20:09:10 CEST] <c_14> so either set -strict experimental or use -pix_fmt yuv420p
[20:12:42 CEST] <JEEB> frenda: it has been for quite a while
[20:13:15 CEST] <JEEB> it was added in HEVC/H.265 version 2 (range extensions)
[20:13:21 CEST] <JEEB> and we're at version 3 by now
[20:13:37 CEST] <JEEB> libx265 had that warning for a while but that was removed quite some time ago as well
[20:13:50 CEST] <JEEB> which means that if you _now_ get that warning, then you are using a very old version of libx265
[20:14:26 CEST] <c_14> Hmm, don't think the patch was applied to ffmpeg yet
[20:14:28 CEST] <c_14> It's on the ml though
[20:15:07 CEST] <JEEB> the ML one was about 12bit I think
[20:15:18 CEST] <JEEB> which is a very recent feature in libx265
[20:15:34 CEST] <JEEB> 4:2:2/4:4:4 have been in libx265 for quite a while by now
[20:15:45 CEST] <c_14> The one I'm looking at is about 4:2:2 and 4:4:4. From the 22nd
[20:15:55 CEST] <JEEB> o_O
[20:15:59 CEST] <JEEB> really?
[20:16:07 CEST] <JEEB> I remembered there was one for 12bit
[20:16:14 CEST] <JEEB> since that lost its warning in libx264 a few days ago
[20:16:20 CEST] <c_14> https://ffmpeg.org/pipermail/ffmpeg-devel/2015-August/177709.html
[20:16:49 CEST] <c_14> Ah, the 12-bit was PATCH 2/2
[20:16:59 CEST] <JEEB> wow
[20:17:05 CEST] <JEEB> 4:2:2/4:4:4
[20:17:08 CEST] <JEEB> ok
[20:17:09 CEST] <JEEB> so yes
[20:18:13 CEST] <JEEB> I guess it shows how much people cared :D
[20:19:25 CEST] <JEEB> that said
[20:19:33 CEST] <JEEB> I'd be surprised if libx265 was fast enough for screen capture
[20:27:48 CEST] <frenda> It's saying `Press [q] to stop, [?] for help`
[20:27:51 CEST] <frenda> I do it
[20:28:05 CEST] <frenda> but it does not stop filming instantly!
[20:28:54 CEST] <frenda> Is it because of libx265?
[20:29:18 CEST] <c_14> It won't be instantaneous, but it should be relatively fast.
[20:30:13 CEST] <frenda> It's over 1 minute I have pressed `q`, but it has not returned to prompt!
[20:30:26 CEST] <c_14> Hmm, try ^c
[20:30:56 CEST] <frenda> I did it once. It destroyed the video!
[20:31:18 CEST] <frenda> Ah, it stoped! over 2 minutes!
[20:31:38 CEST] <c_14> Pressing it once should make it do a regular termination
[00:00:00 CEST] --- Sat Aug 29 2015

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