[Ffmpeg-devel-irc] ffmpeg.log.20130715

[burek]

[00:00] <klaxa> no that'd be BTC ;)
[00:05] <Macey> :)
[00:07] <durandal_1707> Macey: so what is your target fps?
[07:04] <tm512> I am having problems with ffmpeg's recorded sounds playing back at slower, and lower pitched
[07:06] <tm512> the other day, it was working just fine
[16:23] <leandrosansilva> Hello to all. I have an AVFrame with pixel format yuvj420p (read from a jpeg image). How can I access each channel (Y, U and V) from this frame?  It's linesize field is {64, 32, 32, 0, 0, 0, 0, 0}, width = 52 and height = 52
[16:24] <leandrosansilva> ops height = 54
[16:26] <Mavrik> that looks planar
[16:26] <Mavrik> so data[0] is first plane
[16:26] <Mavrik> data[1] second, etc.
[16:26] <Mavrik> judging buy the linesizes
[16:26] <Mavrik> Y is in data[0]
[16:26] <Mavrik> U and V in data[1] and [2] since they're half the first one and you have 4:2:0
[16:33] <leandrosansilva> ok, so as the first plane has size == 64, it means every byte is relative to a pixel?
[16:41] <bencoh> linesize is the size (in bytes) of one line of your picture (including padding/alignement)
[16:41] <bencoh> which means that line2 begins at start+linesize
[16:52] <nb-ben_work> hi :) I am looking for encoding parameters for performance converting a .mov file to .ogv
[16:52] <leandrosansilva>  thx!
[16:52] <nb-ben_work> I want the performance when decoding the file
[16:52] <nb-ben_work> don't care if encoding will take a long time
[17:04] <durandal_1707> nb-ben_work: and what is in mov?
[17:04] <durandal_1707> decoding performance depends on what codec is used
[17:04] <nb-ben_work> hd1080 movie, very high quality
[17:04] <nb-ben_work> im not sure how it is encoded, is it possible for me to check?
[17:06] <nb-ben_work> wonder if this FireFox OS on the raspberry is going to smoothly play this .ogv file I just encoded at full HD
[17:06] <nb-ben_work> if it does I'm gonna go to sleep
[17:06] <nb-ben_work> :D
[17:09] <vincethechimp> If one would want to merge to videos vertically. What would one need to do?
[17:09] <vincethechimp> two*
[17:10] <saste> vincethechimp, overlay
[17:55] <luc4> Hi! When muxing using the libavformat API, is it possible to write to a buffer instead of writing to a file?
[17:55] <JEEBsv> yes
[17:56] <luc4> JEEBsv: I currently use avio_open to open the output file. Should a use a different function maybe?
[17:59] <mapreduce> Do the av* libs give me some hashtable I can use in my own stuff?
[18:27] <SKiTZO>  In what format is video in just before being displayed on screen by a video player, and would it be possible to cache the video in this format?
[19:36] <IchGuckLive> hi i woudt like to shorten my video  for uploading to Youtube  as HD Reaseon is Capacity of Netline
[19:36] <IchGuckLive> http://pastebin.com/6WUkKUh7
[19:36] <IchGuckLive> the file data
[19:37] <IchGuckLive> can someone give me a hint half the size of 180MB so around 90 woudt be a perfect meet
[19:37] <IchGuckLive> or even shorter if  loss is acaptable
[19:37] <klaxa> use -t?
[19:38] <klaxa> you can use libx264 for starters
[19:39] <klaxa> encoding will take longer though, but filesize will decrease
[19:39] <IchGuckLive> on ubuntu i think itas not avalilable
[19:39] <klaxa> --enable-libx264
[19:39] <klaxa> it's compiled with libx264
[19:39] <IchGuckLive> ok
[19:39] <klaxa> try: ffmpeg -i input.mp4 -c:v libx264 -c:a copy output.mp4
[19:41] <klaxa> maybe add -profile:v high
[19:41] <klaxa> so: ffmpeg -i input.mp4 -c:v libx264 -profile:v high -c:a copy output.mp4
[19:41] <JEEBsv> the profile thing does something only if you limit it
[19:41] <JEEBsv> it doesn't do ANYTHING if you make it higher
[19:41] <JEEBsv> (than your current settings)
[19:41] <klaxa> ah
[19:42] <JEEBsv> as in, if your preset doesn't use high profile settings you will not get a high profile flag
[19:42] <JEEBsv> and setting that flag manually won't either
[19:42] <klaxa> makes sense
[19:42] <klaxa> so the preset is actually the important setting?
[19:43] <JEEBsv> preset sets the defaults
[19:43] <JEEBsv> those are then limited by the profile, if profile is set
[19:44] <JEEBsv> presets control defaults (speed vs compression), tune sets possible tunings regarding source material, profile sets the profile you want to limit your stream to, level sets the level flag (does not enforce it! You have to set the refs yourself!)
[19:46] <IchGuckLive> 160MB on 4min
[19:46] <JEEBsv> if you are using the default rate control, then the default is -crf 23
[19:46] <JEEBsv> make it higher to make x264 compress more
[19:46] <JEEBsv> as well as set a slower preset, perhaps?
[19:47] <IchGuckLive> -crf 30 or more
[19:47] <JEEBsv> http://mewiki.project357.com/wiki/X264_Settings#preset
[19:47] <JEEBsv> list ^
[19:49] <IchGuckLive> Change options to trade off compression efficiency against encoding speed as you said but witch way is what
[19:50] <IchGuckLive> Fast speed high compression  slow encoding  no compression
[19:51] <JEEBsv> the faster something goes the generally less things it tries to do
[19:51] <JEEBsv> thus worse compression
[19:53] <IchGuckLive> ok but on finish now i got a 172Mb file at 4:06min  the VLC shows no sound and no picture
[19:55] <IchGuckLive> preset is the goal
[19:56] <IchGuckLive> JEEB q= crf
[19:56] <JEEBsv> no
[19:56] <IchGuckLive> its noe at 29
[19:56] <JEEBsv> q=quantizer
[19:56] <JEEBsv> crf is crf
[19:56] <IchGuckLive> ok
[19:58] <IchGuckLive> down to 150MB at ffmpeg -i gps2013_h.mp4 -preset veryfast -c:v libx264 -c:a copy output_test.mp4
[19:59] <JEEBsv> you are not touching the crf value
[19:59] <JEEBsv> that controls the general quality level
[19:59] <IchGuckLive> no i am
[19:59] <JEEBsv> 23 is default
[19:59] <JEEBsv> no you are not
[19:59] <JEEBsv> I cannot see it
[19:59] <JEEBsv> you just posted your command line
[19:59] <IchGuckLive> i try now with 30
[19:59] <JEEBsv> also faster presets will NOT make shit compress better
[19:59] <JEEBsv> as I said
[19:59] <JEEBsv> the faster the preset, the less stuff is done
[20:02] <IchGuckLive> ok q now at 36 fps has droped to 32  bitrate at 1900
[20:02] <IchGuckLive> 2min at 36Mb
[20:04] <IchGuckLive> finish at 62MB ok so far and quality looks good
[20:05] <IchGuckLive> ffmpeg -i gps2013_h.mp4 -preset faster -c:v libx264 -crf 30 -c:a copy output_test.mp4
[20:07] <IchGuckLive> http://www.youtube.com/watch?v=QD9gdCy6mNE this took 4hr to upload on 180MB Now i will be 3hr faster  THANKS
[20:09] <IchGuckLive> i will overview the kdenlive  video output generator to do it as it renders  in first place
[20:13] <brontosaurusrex> isnt kdenlive using some sort of scripting engine? IchGuckLive
[20:13] <brontosaurusrex> for the timeline i mean
[20:13] <IchGuckLive> it uses
[20:13] <brontosaurusrex> perhaps that is pipe-able to ffmpeg directly?
[20:13] <IchGuckLive> no for rendering
[20:16] <IchGuckLive> ishoudt try this with only 20sec vid  as it takess 5min all the time to generate
[20:16] <IchGuckLive> ok it works for me thanks alot to the heölpers and by
[00:00] --- Tue Jul 16 2013