x264 rev. 2074 - part of image jumping with some presets and strange bitrate dependance

[Dimon]

I have almost fully static 1920x1080p 25fps scene: dark bottom with some tree branches shaking within no more then 10 pixels and slow clouds passing by. In 30 sec of the whole scene there are couple of ~2 sec chunks, where bottom of the image begin to jump with ~0.2 sec period, up and down with visual amplitude 8-16 pixels. This happens only with "--preset" settings slow, slower and "harder". More "light" presets work pretty. Initial file is .mts, decoded through ffdshow/AviSynth. The command line is:

x264 --preset slower -b 6 -r 8 --crf 18 -o file.mkv file.avs

Players were Classic Media Player and VideLan VLC, showing the same.

Varying -b and -r parameters doesn't help, so lack of memory for decoding is not very probable reason (Core Duo 2.8 GHz, 2GB RAM)

Also, in this and close situation, with only slooowly moving and transforming clouds in the frame: veryfast, faster, fast, normal presets sequence gives growing bitrate! When visualising motion vectors in ffmpeg plugin, more "hard" preset shows longer vectors.

[Carl Eugen Hoyos]

Please explain if there is a problem with FFmpeg and if yes what the problem is.
(x264 is a different, independent application.)

[Dimon]

No ,actually FFmpeg itself doesn't cause any problem.

I'm here from VideoLAN page.
​http://www.videolan.org/developers/x264.html "BUGS" in the bottom

If I am at the wrong address please delete the ticket.

[Carl Eugen Hoyos]

First read the FFmpeg bug report guidelines.
Then report your bug to ​http://mailman.videolan.org/listinfo/x264-devel