[claudio_b_p]

Hello.

When watching avi and mkv when I select to play another part of the movie the sound does not come back. I only get the video with no sound.

The files are large from 700 MB to 4500 MB.

Sometimes the sound comes several seconds (sometimes aprox. 10).

Some files I get points of the movie that the video pauses itself. I have to fast forward a few seconds to get the movie to continue playing.

I have a Nokia E7 with Belle.

¿Are this issues normal to Belle or are caused by a bad update from Anna?

[Raoul_Duke · Accepted solution]

Hi claudio_b_p,

Thanks for you post.

I don't think issue is caused by firmware of the device but rather how the file has been encoded, the profile level the file is using and the codec itself as this issue happens to me also using several different devices including non Nokia handsets and even dedicated media players and even on my P.C as well. Sometimes if you leave it say 10 to 20 seconds the sounds eventually catches up.

I've never really worked out what the issue is as it doesn't happen with all MKV files but some but I suspect it has something do to with hardware, software decoding and the way the MKV file itself has been encoded. The MKV file is just a container (For more reading about MKV please refer to this link http://www.matroska.org/index.html) which holds the video stream. The majority of video streams in an MKV is H.264. These are then encoded according to certain encoding level profiles. Profiles define the sets of bit stream features the h.264 stream can use. Levels define restrictions on the video resolution, frame rate and VBV (Video Buffer Verifier) etc. In short, Level 5.1 uses four to five times the bandwidth of Level 4.1 and hence allows very high definition video, 4096×2304 at 25 or similar. So you could have an MKV but the profile level could be so high that the hardware just doesn't support it even though it supports MKV. Most spec sheets of devices do state what profile level MKV's support. For a non dedicated media player such as a mobile device it is not recommended to go above 4.1.

For more reading into the H.264 codec please refer to this link:

http://en.wikipedia.org/wiki/H.264/MPEG-4_AVC

I personally don't believe it has anything to do with Anna or Belle but hardware limitations and the way the MKV file has been encoded. Best thing to do is to check the MKV file that you are using. To find out the profile level of a file you will need to use a media tool as you can't simply check it by looking into the property of the file. A good tool to check media file information is Mediainfo which is a free application.

Try a variety of video files such as mp4, avi, xvids etc and see if you experience the same issues.

Hope this helps.

Regards

Raoul_Duke