15:15:19 < niez> how can I open video from memory buffer in 9.X? in 0.8.X I used ByteIOContext (now AVIOContext) and av_open_input_stream(), now I should use avformat_open_input() but how should I use ByteIOContext with that?
15:20:26 < niez> ok, I can create AVFormatContext with avformat_alloc_context(), but what next?
15:21:22 < JEEB> unless there's a pre-made in-memory AVIO thingy, you just have to implement three or so functions that implement the IO
15:22:33 < niez> yes, I have done that, I used avio_alloc_context()
15:22:52 < niez> and now I have AVIOContext
15:22:54 <@elenril> niez: that's documented in avformat_open_input() doxy
15:23:05 <@elenril> you preallocate the context, then set its pb element
15:23:18 <@elenril> then call avformat_open_input()
15:23:26 < niez> ach, ok
15:23:55 < niez> ok, everything is clear now
15:23:59 < JEEB> :)
15:24:07 -!- moser [~moser@59.42.82.226] has joined #libav
15:24:07 < JEEB> I implemented this for an MS API some months ago
15:24:18 -!- D4RK-PH0ENiX [~D4RK-PH0E@73.199.192.61.east.global.crust-r.net] has quit [Read error: Connection reset by peer]
15:24:50 -!- D4RK-PH0ENiX [~D4RK-PH0E@73.199.192.61.east.global.crust-r.net] has joined #libav
15:25:54 < niez> cool, it works
15:40:08 < niez> ok, last issue, avg_frame_rate.den == 0
15:40:14 < niez> any hints?
15:42:41 <@elenril> did you call find_stream_info()?
15:44:40 < niez> hm...
15:46:22 <@elenril> and note that in general you cannot rely on it being set to anything meaningful
15:46:31 <@elenril> e.g. when the container does not provide any timestamps
15:47:40 -!- tpyo [~tpyo@31-209-245-236.dsl.dynamic.simnet.is] has joined #libav
15:48:37 < niez> yes, I'm using this function, it was av_find_stream_info in 0.8.x, I've changed it to avformat_find_stream_info(formatContext, NULL);
15:48:45 -!- tpyo [~tpyo@31-209-245-236.dsl.dynamic.simnet.is] has quit [Client Quit]
15:49:07 <@elenril> what is the container?
15:49:18 <@elenril> and are you setting any AVFormatContext options?
15:49:20 < niez> ogg works good
15:49:51 < niez> avi and mp4 have problems with that
15:50:14 < niez> no, I didn't sen any options
15:52:17 <@elenril> what does avconv say on such files?
15:53:32 < niez> how should I run it? which options?
15:54:10 <@elenril> just avconv -i <file>
15:55:32 < niez> http://pastebin.com/cBRw1vKG
15:57:41 < niez> here is output for ogg: http://pastebin.com/84fVkmUK
15:58:02 < niez> fps: 24 appears only for ogg
15:59:08 < niez> it looks like I can use tbn or tbc values as fps, am I right?
16:00:39 <@elenril> it won't work in all cases
16:03:29 < niez> tbn != fps in general? or this valye is sometimes missing?
16:03:47 <@elenril> tbn is the stream timebase
16:03:59 <@elenril> that is the units that are used for the timestamps
16:04:05 <@elenril> those can be completely arbitrary
16:04:15 <@elenril> e.g. in matroska you'll usually get 1/1000
16:05:33 < niez> ok, so, avconv didn't display fps - it couldn't get that ifo from my file?
16:07:18 <@elenril> apparently
16:07:21 <@elenril> looking into that now
16:07:54 < niez> I have used big buck bunny video from website for testing
16:13:26 < niez> well, in my application I can assume 25fps for every video, I can hardcode num and den for now
16:19:09 <@elenril> hmm, seems it's the usual libavformat timestamps insanity
16:19:37 <@elenril> i'll do something about it in git master, but don't expect it to be backported to releases, as it might break some obscure cases
16:19:53 <@elenril> in general you shouldn't rely on avg_frame_rate too much anyway
16:20:17 < niez> ok, what should I do in general then?
16:20:26 <@elenril> what do you need it for?
16:21:02 <@elenril> in general your video can be vfr, so the average framerate is some potentially meaningless number
16:21:12 < niez> oh, yes, in my application I can hardcode 25fps, but what about general video player? how to determine fps?
16:21:13 -!- Spamoi [~Spamoi@134.117.39.62.rev.sfr.net] has quit [Ping timeout: 240 seconds]
16:21:44 < niez> vfr?
16:21:49 <@elenril> variable frame rate
16:22:00 <@elenril> i.e. non-constant frame durations
16:22:08 < niez> in case of network vodeo stream or something?
16:22:39 <@elenril> various webcams or desktop grabbers often produce vfr
16:23:08 < niez> anyway, strange things, so how can you tell at what time display next frame?
16:23:16 <@elenril> by looking at the timestamps
16:23:28 <@elenril> AVPacket.pts / AVFrame.pkt_pts
16:23:47 < niez> ach, ok