[Ffmpeg-devel-irc] ffmpeg.log.20131211

burek burek021 at gmail.com
Thu Dec 12 02:05:01 CET 2013

[00:01] <saste> gazarsgo, crop and/or pad and/or scale
[00:02] <gazarsgo> these filters are pretty powerful, thanks. sorry about the stream of consciousness
[00:10] <lenswipe_dev> hey guys
[00:11] <lenswipe_dev> anyone know if ffmpeg can play an m4a stream?
[00:11] <sacarasc> ffplay probably can.
[00:19] <llogan> lenswipe_dev: ffmpeg -i input.m4a -f alsa -ar 44100 hw:0
[00:19] <lenswipe_dev> llogan, It's actually via node.js but thanks
[00:20] <lenswipe_dev> i wanted to know if ffmpeg had the capability to do it
[00:20] <llogan> yes, ffmpeg can playback an audi ofile via alsa output device
[00:20] <llogan> or oss or pulse
[00:21] <llogan> ...and sndio
[00:21] <llogan> but maybe you weren't asking about playback
[00:33] <lenswipe_dev> llogan, well for one thing - i can absolutely garuntee it wont be via alsa :p
[00:33] <lenswipe_dev> this is on a windows host :P
[01:33] <jack_thompson> is there an simple/example player like ffplay that compiles only with the development files installed?
[01:34] <jack_thompson> the included ffplay requires libavutil/colorspace.h which isn't part of the development files...
[01:34] <jack_thompson> so to compile it i still need the complete source.. (in which it is included)...
[01:35] <jack_thompson> but i'd like to have an example that decodes video/audio to sdl...
[01:35] <jack_thompson> just like ffplay does...
[01:35] <jack_thompson> but an example that compiles separately from the /entire/ codebase... like a project using libavcodec would do..
[01:36] <jack_thompson> is there a very very simple player like ffplay?
[01:36] <jack_thompson> somewhere?
[01:37] <jack_thompson> i dont have time to make ffplay compile with only the development files...
[06:45] <aplund> is there any way to get seek and duration parameters to match the titles and chapters of a dvd (when using /dev/dvd as an input) ?
[06:46] <aplund> as in, a way built into ffmpeg and not needing another utility
[07:21] <aszlig> good morning
[07:24] <aszlig> what's the easiest way to send async a/v to a remote stream using one audio stream and two video streams as input?
[07:24] <aszlig> having a hard time to find any resources on the web, because most people would see async audio/video as a problem rather than the desired effect
[07:31] <aszlig> https://redmoonstudios.org/~aszlig/fdbc/stream.sh <- this is how i'm using it right now
[07:32] <aszlig> if i use it without the external tcp://-stream audio works fine, but with the tcp stream i get audio dropouts
[07:34] <aszlig> so i'm just assuming this to be a sync issue, because video runs without frame drops but audio is stuttering
[08:13] <aszlig> hm, never mind, this seemed to be an issue on the remote service
[08:13] <aszlig> thanks anyway
[09:33] <Schtern> how do I set bitrate in ffmpeg
[09:33] <JEEB> for overall average bit rate, -b:v for video, -b:a for audio
[09:34] <Schtern> I've used -bitrate flag before, however doesn't work
[10:06] <stonie_> how may i force interlaced mpeg2? i try "-flags +ildct+ilme -top 1" - from the header its tff but in premiere it looks progressive?
[10:16] <re-G> is there 'official' ultrafast preset any more?
[10:18] <re-G> oh, it's internal. without preset file
[10:21] <relaxed> re-G: `x264 --fullhelp` to see it
[10:54] <stonie_> how do i interlace material?
[10:55] <stonie_> into mpeg2
[13:17] <vivienschilis> hi guys
[13:17] <vivienschilis> is it prossible to do ffprobe -show_frames
[13:17] <vivienschilis> limitting the number of frames to inspect
[13:25] <saste> vivienschilis, -read_intervals
[13:36] <vivienschilis> saste: thanks
[15:13] <grkblood13> does signed 16bit encoding use two's complement for negative numbers?
[15:16] <zap0> 16bit encoding of what?
[15:18] <grkblood13> pcm
[15:18] <grkblood13> pcm_s16le
[15:35] <JEEB> I would say it's a standard 16 bit signed value, little endian :P
[15:41] <Mavrik> which means it does :)
[17:00] <chele> Hello guys. Is there a way to extract the timestamps of a H263 video stream recieved from a peer terminal?
[17:02] <Mavrik> chele, ffprobe -show_frames <your input>
[17:03] <Mavrik> use -print_format parameter to make output something easily parsable for you :)
[17:16] <chele> Mavrik: And could I build .3gp from that? The thing is I receive H263 bit stream from a peer and I need somehow to build .3gp. I receive also the audio bit stream but that one is fixed(AMR_NB).
[17:17] <chele> I'm reading 3gp file format spec and without the timestamps I could not build .3gp and reproduce it at the peer side. Is there any way to get/guess/calculate this information?
[18:02] <DeadSix27> anyone an idea why every frame is being dropped? (i used that command line before, and it worked fine then)
[18:02] <DeadSix27> see: http://pastebin.com/4reBN9Jh
[18:05] <DeadSix27> oh i forgot 1 parameter
[18:06] <DeadSix27> well that disabled sound
[19:06] <LucaS05> hi. i want to simulate the xvid codec. is it possible with ffmpeg?
[19:09] <angell> Hello everyone, I'm writing a program to play video files (mainly wmv, mp4, avi and mpeg files). However, I'm looking for a way to play these files from memory, in other words, supplying the control a pointer to the memory block where the file is, instead of supplying it a file path. Any suggestions?
[19:16] <llogan> LucaS05: yes. also ffmpeg can use the external encoder libxvid
[19:17] <llogan> or using the native encoder: ffmpeg -i input -c:v mpeg4 -vtag XVID -q:v 4 output.avi
[19:17] <llogan> ok!!!
[19:38] <L3top> Hello. New to ffmpeg. Trying to reduce some file sizes to fit on dvds. I have ffmpeg -i final.mpg -ab 32k -r 29.97 -aq 1 -qscale 7.5 finalnew.mpg
[19:38] <L3top>  which I am pretty happy with... but the audio is out of sync by about half a second. Any clues on how I might correct this?
[19:39] <llogan> ffmpeg has "-target ntsc-dvd"
[19:40] <llogan> also -aq and -ab are mutually exclusive
[19:40] <llogan> and -r 29.97 should be -r ntsc or -r 30000/1001
[19:43] <L3top> ty
[19:43] <L3top> I see there is a map function and offset to handle my synch problem
[19:44] <DeadSix27> is it normal that encoding in vp8 barerly uses my cpu?
[19:44] <LucaS05> do you have some advices for developing a codec with ffmpeg?
[19:44] <DeadSix27> i mean x264 uses pretty much my whole processing power
[19:45] <DeadSix27> while on vp8 it doesnt even use 40%
[19:45] <JEEB> libvpx is crappily optimized compared to libx264
[19:46] <JEEB> so if you want to encode VP8 or VP9 with it, enjoy
[19:46] <DeadSix27> is there a better ?
[19:46] <JEEB> for vp8 there for a moment was a project called xvp8, but that was a really fleeting thing, and died off rather quickly
[19:46] <JEEB> because people just didn't care
[19:47] <DeadSix27> well i do care!
[19:47] <DeadSix27> guess that wasnt enough
[19:47] <JEEB> VP8 was a worse format than  >(constrained baseline) H.264, and x264 was already a highly optimized, oiled machine as an encoder. And thanks to adobe flash and even browser support, H.264 really wasn't a worse alternative.
[19:47] <JEEB> soo... yeah
[19:48] <DeadSix27> why "was" ß
[19:48] <DeadSix27> ?
[19:48] <DeadSix27> imo its still
[19:48] <llogan> waß
[19:48] <JEEB> because VP9 is already out and VP8 is even less useful etc.
[19:48] <DeadSix27> does ffmpeg support vp9?
[19:49] <DeadSix27> (encoding)
[19:49] <JEEB> yes, via a new enough libvpx
[19:49] <DeadSix27> ah libvpx-vp9
[19:49] <DeadSix27> uses even less cpu power
[19:50] <JEEB> do note that while VP9 is kind of more useful, it's also very, very much more slower
[19:50] <JEEB> yes
[19:50] <JEEB> also VP9 lacks a specification, and Google doesn't seem to see this as a problem :P
[19:50] <DeadSix27> does youtube use vp9? or vp8 still?
[19:50] <DeadSix27> i assume vp9
[19:50] <llogan> L3top: generally you shouldn't experience a sync problem in the first place
[19:51] <JEEB> it does use vp9 for some videos, generally vp8 if you want to note only the VPx formats
[19:51] <JEEB> it does still use mostly H.264
[19:51] <DeadSix27> ye
[19:51] <DeadSix27> i know
[19:51] <JEEB> in one way or another
[19:51] <DeadSix27> i just meant the vpx videos
[19:51] <L3top> I think it was related to that mutually exclusive thing llogan. Once I eliminated and began tweaking it went away.
[19:51] <L3top> thanks again
[19:51] <DeadSix27> i dont have webm enabled on youtube though
[19:52] <DeadSix27> h264 in flash runs smoother (atleast in their setup)
[19:52] <JEEB> x265 is looking good performance-wise, but the developers have nothing to do with x264 :)
[19:52] <DeadSix27> i noticed so
[19:52] <DeadSix27> you think its going to be a good successor?
[19:52] <JEEB> the format is good (HEVC/H.265)
[19:52] <DeadSix27> yep h265
[19:52] <JEEB> it was known as HEVC before that :)
[19:52] <DeadSix27> but i mean.. x264 was pretty revolutionary
[19:52] <DeadSix27> look how often its used
[19:53] <JEEB> x264 actually is a pretty goddamn good encoder :D
[19:53] <DeadSix27> yep
[19:53] <DeadSix27> and thats why i asked
[19:53] <JEEB> anyways, x265 can already beat x264 in numbers, but the result is not as pretty
[19:53] <DeadSix27> "you think its going to be a good successor?"
[19:53] <DeadSix27> we'll see i guess
[19:53] <JEEB> in numbers as in SSIM
[19:53] <JEEB> yes, we'll see
[19:53] <DeadSix27> as soon ffmpeg supports encoding of x265 ill try it out more widely
[19:53] <JEEB> they've been ripping out things from x264 and sticking them into x265
[19:54] <JEEB> it has worked out relatively OK
[19:54] <DeadSix27> I did download a x265 build but was to lazy to try it out further
[19:54] <JEEB> http://fushizen.eu/u/jeeb/2013-12-03-x265_x264_test/hyouka_op/
[19:54] <JEEB> you can compare these
[19:54] <DeadSix27> gotta love the hyouka op
[19:54] <JEEB> the ssim directory contains the raw SSIM data
[19:54] <JEEB> on the clips
[19:55] <JEEB> Total: 13.501    (Y': 12.4967   Cb: 16.1191   Cr: 17.3511 ) , and x264 Total: 13.4168   (Y': 12.5562   Cb: 15.3001   Cr: 16.6475 )
[19:55] <DeadSix27> did you downscale the 1080p bd?
[19:55] <JEEB> yes
[19:56] <JEEB> to 720p
[19:56] <DeadSix27> noticed
[19:56] <DeadSix27> well picture-wise my bad eyes cant spot a diference
[19:56] <DeadSix27> except in the numbers
[19:56] <JEEB> x265 blurs a lot
[19:57] <DeadSix27> also, as we talked.. vp9 was still encoding
[19:57] <DeadSix27> (a 1:30m video)
[19:57] <DeadSix27> and is still encoding*
[19:57] <DeadSix27> terrible fps rate
[19:57] <DeadSix27> of 1.1
[19:58] <JEEB> I think with this (--preset placebo for both, --tune ssim for x264 and --aq-mode 1 for x265) I had a 3.5fps with x264 and 0.7fps or so with x265? Don't remember exactly
[19:59] <JEEB> multithreading-wise x265 looks pretty good at least
[19:59] <DeadSix27> whats your hardware?
[19:59] <JEEB> i5 3570K
[19:59] <JEEB> standard clocks
[19:59] <DeadSix27> idk much about intel
[19:59] <DeadSix27> is that a quad ?
[19:59] <JEEB> yes
[19:59] <JEEB> ivy bridge
[19:59] <DeadSix27> on my 6core amd i get usually 4-5fps on x264
[19:59] <DeadSix27> with similiar settings
[20:00] <DeadSix27> didnt test x265
[20:00] <DeadSix27> but its OC'd
[20:00] <DeadSix27> anywway
[20:00] <DeadSix27> gotta drink a tee while vp9 is encoding
[20:01] <DeadSix27> guess i have enough time
[20:01] <JEEB> x265 was much less useful until someone from outside of the project came and posted a CRF patch that implanted the x264's CRF ABR into x265
[20:02] <JEEB> because 1pass ABR is...
[20:02] <JEEB> uhh
[20:02] <JEEB> it sucks
[20:02] <DeadSix27> "outside thw project"
[20:02] <DeadSix27> someone of x264 ?
[20:03] <JEEB> nah
[20:03] <JEEB> just some random chinese guy methinks
[20:03] <JEEB> posted a patch on the mailing list
[20:03] <DeadSix27> lol.
[20:06] <llogan> was it "The Chinese Guy"?
[20:20] <rager> hullo folks
[20:21] <rager> I've gotten a bit further in my quest to make ffmpeg work nicely for me on android
[20:21] <rager> JJMpeg lets me pretend that I'm using java libs instead of C ones - I figure I can actually write some JNI code after I understand the API's better
[20:24] <rager> how would I go about extracting metadata from my video stream to determine orientation?
[20:27] <JEEB> if it's in the container, you should be looking at how ffprobe/ffmpeg read it from libavformat's information
[20:27] <JEEB> it should be available in a field in libavformat
[20:28] <rager> it's a weird java wrapper that lets you write the glue code in java instead of C to interact with libav
[20:28] <llogan> if it's metadata look for "rotate=90" or something like that
[20:29] <rager> http://ffmpeg.org/pipermail/ffmpeg-devel/2011-March/109915.html < found this, at least
[20:29] <llogan> the metadata my be specific to the stream and not global, but i don't really know
[20:30] <DeadSix27> llogan: no it was the "random chinese guy"
[20:30] <DeadSix27> not chinese guy in general.
[20:32] <JEEB> if he meant the chinese guy who had a couple of commits in x264 from '04, it wasn't him. I think he's currently working on the x265 project paid by MCW, though.
[20:32] <saste> rager, also: doc/examples/metadata.c
[20:32] <rager> ah, thanks
[20:33] <llogan> JEEB: yes, that's who i was referring to.
[20:33] <saste> JEEB, you're in the field since a long time
[20:34] <saste> if you remember people from the past 2004 (I can't even say what I was then ehehe)
[20:34] <JEEB> I only remember that guy because he also was open sourcing his own "x265" and we noticed he actually had a couple of commits when we looked into it
[20:34] <JEEB> *couple of commits in x264
[22:08] <SirCmpwn> I'm losing timing info between frames when using GIFs as input sources
[22:09] <SirCmpwn> just ffmpeg -i foobar.gif ...
[22:32] <zap0> 999% of GIFs are badly encided
[22:33] <zap0> 99.9   encoded/
[22:34] <DeadSix27> 99.9 peroid?
[23:38] <llogan> SirCmpwn: maybe you can use -default_delay if the delays are not variable... but i've never really messed with gifs
[00:00] --- Thu Dec 12 2013

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