10-05-2011, 09:31 PM #1
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BDP7600: Bug with fast forward, chapters and time search during playback of MKV files
I bought my 7600 mainly because of its capabilities playing Matroska files (file extension mkv). My mkv files consist of an MPEG2 video and MP2 audio stream made from DVB-S SDTV recordings. Software version is 1.09.
I found out that fast forward up to 32x, chapter selection or time search only work with part of my mkv files. With other mkv files fast forward is only possible up to 4x (pressing FF on the remote results not in 8x FF speed but in jumping to the next video), chapter selection or time search immediately result in a freezed playback. The software seems to be crashed but if one presses the button "return to a previous display menu", the player returns to the file list display.
Needless to say that all mkv files work as expected if played on a PC with e. g. VLC media player.
The problem on the 7600 isn't related where the files come from: It's the same from a USB drive (no matter if FAT32 or NTFS) and from a DLNA server.
After some extensive testing and analysis of the mkv files I found out that the problem has nothing to do with the actual stream data but with the Matroska "envelope" around the streams. The difficult files use a certain Matroska file format element ("CueCodecState") that seems to be incorrectly interpreted by the 7600.
I'd greatly appreciate if some Philips guy could get this checked and - best - fixed in a future firmware release. Thanks.
Some additional information. Mainly intented for developers to describe how testing was done:
- TS files from TV recordings are demuxed with "ProjectX".
- Muxing of the m2v and mp2 files is done with "mkvmerge" from the tools "mkvtoolnix".
- For testing I used just one m2v stream that was muxed into an mkv file (the problem is not dependent on the usage of audio streams).
- With version 3.3.0 of mkvmerge the muxed MKV file works as expected. With version 3.4.0 and all later versions the problems occur. (Even with the same m2v file, so not related to the stream content.)
- mkv files compared with the EBML tree viewer from AVI-MUX GUI. Main difference: The elements "CodecState" and "CueCodeState" are used in version 3.4.0 and later. They provide additional information for the demuxer.
- The problem can be enforced with version 3.3.0 by using the option "--engage use_codec_state".
- Usage of the tool mkclean on difficult files leads to files that play correctly. Analysis shows that mkclean strips off the elements "CueCodecState" but not "CodecState". So the former one seems to be the only cause.
- Possible solution: Player reads the element CueCodecState correctly (but does not use the provided information).