How to skip until first key frame without decoding

[s_kamiya at toa.co.jp]

Hi, Mr.Nicolas.

Thank you for your information.
I did not notice this specification. So it's helpful for me.

I tried GST_SEEK_FLAG_SNAP_AFTER and I noticed the following.

If I generate a movie by seeking with GST_SEEK_FLAG_SNAP_AFTER and 
GST_SEEK_FLAG_FLASH, 
it will appear distorted green for the first few seconds when I play with 
gst-play.

If you know the reason, could you tell me it?

My purpose is that the beginning of the movie becomes a key frame.
So for the time being, I would like to select one of the following.

1. GST_SEEK_FLAG_SNAP_AFTER without GST_SEEK_FLAG_FLASH
2. GST_SEEK_FLAG_SNAP_BEFORE  with GST_SEEK_FLAG_FLASH
3. GST_SEEK_FLAG_SNAP_NEAREST  with GST_SEEK_FLAG_FLASH

I think GST_SEEK_FLAG_SNAP_BEFORE is also fine.
Because I confirmed that If I use GST_SEEK_FLAG_SNAP_BEFORE and there is 
no previous key frame, it seeks to the next key frame.

Best regards,
Kamiya.


"Nicolas Dufresne" <nicolas at ndufresne.ca> wrote on 2023/09/07 02:39:21:
> 
> Le mardi 05 septembre 2023 ? 17:33 +0900, geysee via gstreamer-devela 
?crit :
> > Hello,
> >
> >
> > I tried the following pipeline with C++ coding (Properties are 
omitted).
> >
> >
> >      pipeline1 : splitmuxsrc ! h264parse ! queue ! qtmux ! filesink
> >
> >
> > When I seek range "start", I would like to skip frame until first key 
frame
> > without decoding.
> >
> > Would you give me how to do it anyone?

> If you issue a seek, qtdemux will send picture from the previous 
keyframe.
> Using GST_SEEK_FLAG_KEY_UNIT | GST_SEEK_FLAG_SNAP_AFTER should 
> instead give you
> frames from the next keyframe (for supported demuxers).

> Nicolas

> >
> > Best regards,
> > Kamiya

> [添付ファイル "C.htm" は 神谷 茂治/TOA が削除しました] 
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