First second of output video frozen when video stream copied and audio stream transcoded for Sony H.264 file

[horshack]

Summary of the bug:

When performing a video copy (-c:v copy) and any audio transcode (ex: -c:a aac) of a Sony H.264 file (Sony A7s/A6300/etc..), the first second of video in the output file is frozen while the audio plays normally. The problem doesn't occur if -copyinkf is specified, even though the first frame of the H.264 input video is a keyframe. When comparing the generated files of -copyinkf specified vs not specified, the file without -copyinkf has 0.45 seconds of audio frames (stream #1) before the first video frame (stream #0), whereas the file with -copyinkf has video as the first frame (stream #0).

How to reproduce:
ffmpeg -i C0002.MP4 -c:v copy -c:a aac output.MP4

Sample C0002.MP4 source video (90MB) can be downloaded at:
​https://drive.google.com/open?id=0Bx7l38U9UxF8cGlScjZnYjBnMDA

[Carl Eugen Hoyos]

I get bit-identical output both with and without -copyinkf.