[FFmpeg-trac] #3083(undetermined:new): Suspicion that valid random access point is not marked as keyframe in AVCHD samples from Panasonic Lumix GH1

FFmpeg trac at avcodec.org
Fri Oct 25 18:39:26 CEST 2013


#3083: Suspicion that valid random access point is not marked as keyframe in AVCHD
samples from Panasonic Lumix GH1
-------------------------------------+-------------------------------------
             Reporter:  rmk          |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:
  undetermined                       |  unspecified
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 AVCHD files from a camera (Panasonic Lumix GH1) demux and
 decode with libavformat/libavcodec detecting no other keyframe but the
 first (both, the first video packet and video frame are marked as
 keyframe), which is not what I would have expected for those clips as
 the GOP structure of files produced by this camera is known to be
 different.

 I observed the following things when looking at the 720p sample:

 - there are no recovery point SEIs or IDRs after the first frame
 - before every I-frame/slice there is an SPS
 - seeking in these files works fine in FCPX import dialog, so I guess they
 do not decode the entire file on every seek (they do however maybe use
 auxiliary AVCHD files to find these random access points)
 - the stream decodes fine if one takes just the packets starting from a
 packet that contains an I-slice

-- 
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/3083>
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