Re: [Libav-user] Why does av_seek_frame() not seek to a keyframe?

2012-07-19 Thread Michael Bradshaw
On Thu, Jul 19, 2012 at 1:54 PM, Hendrik Leppkes wrote: >[...] > If you want to do accurate seeks with only avformat, you have to add a lot > of boilerplate on top of it right now - or if you want to do accurate seeks > even with ffmpeg. Sure, if you tell it to seek, it'll output an image, but > i

Re: [Libav-user] Why does av_seek_frame() not seek to a keyframe?

2012-07-19 Thread Michael Bradshaw
On Thu, Jul 19, 2012 at 1:16 PM, Don Moir wrote: >[...] > I did some visual inspection seeking here and there with my own app and the > above file does not seem to be a problem. When I get a chance I will look at > the numbers to check the accuracy. Just doing the visual inspection may not > be en

Re: [Libav-user] Why does av_seek_frame() not seek to a keyframe?

2012-07-19 Thread Hendrik Leppkes
On Thu, Jul 19, 2012 at 9:47 PM, Michael Bradshaw < mbrads...@sorensonmedia.com> wrote: > > > Visually, things look ok (aside from the frame being ~1.5 seconds > after the requested time), but I think that's because ffmpeg just > keeps reading and decoding until it gets a full frame out, and it > w

Re: [Libav-user] Why does av_seek_frame() not seek to a keyframe?

2012-07-19 Thread Michael Bradshaw
On Thu, Jul 19, 2012 at 12:42 PM, Carl Eugen Hoyos wrote: > [...] > Afair, Reimar believes the seek function should not try hard to find > a keyframe because seeking faster is more important. I think the current functionality is OK, provided it's documented well. Though to be honest I'd like an a

Re: [Libav-user] Why does av_seek_frame() not seek to a keyframe?

2012-07-19 Thread Don Moir
- Original Message - From: "Michael Bradshaw" To: "This list is about using libavcodec, libavformat, libavutil,libavdevice and libavfilter." Sent: Thursday, July 19, 2012 1:13 PM Subject: Re: [Libav-user] Why does av_seek_frame() not seek to a keyframe? On Thu, Jul 19, 2012 at 12:18

Re: [Libav-user] Why does av_seek_frame() not seek to a keyframe?

2012-07-19 Thread Carl Eugen Hoyos
Michael Bradshaw writes: > >> But when I seek, the first packet returned out of the demuxer is > >> not a keyframe packet, and I have to read several (~45ish) packets > >> until I encounter a keyframe. > > > > Could you provide a sample that does not seek to a keyframe with > > ffmpeg -ss x -i in

[Libav-user] Using libav without command line?

2012-07-19 Thread phienkaka
Hi everyone! I using this command bellow for converting file "./avconv -i inputFile -vcodec libx264 -trellis 2 -crf 23 -tune psnr -vf crop='trunc(iw/2)*2:trunc(ih/2)*2' -y outputFile" But, I don't want to using this command, I want to make a function like convert(char *inputFile, char *outputFile).

[Libav-user] How do I specify a bitstream filter using the ffmpeg API

2012-07-19 Thread declan harrison
Hi Guys I have a problem creating MPEG2-TS files when using the ffmpeg API. I get the following error thrown by ffmpeg "H.264 bitstream malformed, no startcode found, use the h264_mp4toannexb bitstream filter (-bsf h264_mp4toannexb)". On the CLI interface I can easily specify the bitstream filte

Re: [Libav-user] Why does av_seek_frame() not seek to a keyframe?

2012-07-19 Thread Michael Bradshaw
On Thu, Jul 19, 2012 at 2:54 AM, John Stebbins wrote: > Another alternative is libav supplies a helper function that does this for > you. The API for such a helper would have a parameter to set the seek > window. The advantage to libav providing a helper function for this is > libav has more info

Re: [Libav-user] Why does av_seek_frame() not seek to a keyframe?

2012-07-19 Thread Michael Bradshaw
On Thu, Jul 19, 2012 at 12:18 AM, Carl Eugen Hoyos wrote: > Michael Bradshaw writes: > >> But when I seek, the first packet returned out of the demuxer is >> not a keyframe packet, and I have to read several (~45ish) packets >> until I encounter a keyframe. > > Could you provide a sample that doe

Re: [Libav-user] c++ API h264 encoded video does not play on all platforms

2012-07-19 Thread Drabner
I found (and posted) the solution to this: http://stackoverflow.com/questions/11537830/ffmpeg-api-h264-encoded-video-does-not-play-on-all-platforms/11558127#11558127 -- View this message in context: http://libav-users.943685.n4.nabble.com/c-API-h264-encoded-video-does-not-play-on-all-platforms-t

Re: [Libav-user] Why does av_seek_frame() not seek to a keyframe?

2012-07-19 Thread John Stebbins
On 07/19/2012 09:25 AM, Carl Eugen Hoyos wrote: Hendrik Leppkes writes: On Thu, Jul 19, 2012 at 8:31 AM, Carl Eugen Hoyos wrote: Isn't this necessary for some codecs / at least for H264? Wouldn't the API do exactly the same? Sure, if you end up seeking to a non-keyframe, it should not decode

Re: [Libav-user] Why does av_seek_frame() not seek to a keyframe?

2012-07-19 Thread Hendrik Leppkes
On Thu, Jul 19, 2012 at 9:25 AM, Carl Eugen Hoyos wrote: > So if the file is ~2GB and (as a user) I seek approximately to > the middle of the video and decide to seek back then, the > video should be decoded from the beginning to find the keyframe > before the position I want to seek to? > (I am

Re: [Libav-user] Why does av_seek_frame() not seek to a keyframe?

2012-07-19 Thread Carl Eugen Hoyos
Hendrik Leppkes writes: > On Thu, Jul 19, 2012 at 8:31 AM, Carl Eugen Hoyos wrote: > Isn't this necessary for some codecs / at least for H264? > Wouldn't the API do exactly the same? > > Sure, if you end up seeking to a non-keyframe, it should not > decode garbage frames. > The point here is

Re: [Libav-user] Why does av_seek_frame() not seek to a keyframe?

2012-07-19 Thread Hendrik Leppkes
On Thu, Jul 19, 2012 at 8:31 AM, Carl Eugen Hoyos wrote: > > Isn't this necessary for some codecs / at least for H264? Wouldn't > the API do exactly the same? > Sure, if you end up seeking to a non-keyframe, it should not decode garbage frames. The point here is that we would want to actually en