Does switching containers necessitate re-encoding?

[gx240]

I understand that if you alter a video or audio stream you have to re-encode, but can you change the number or type of streams or change the container without re-encoding?

For example, say I have an old video file in an avi container with XVID video and mp3 audio accompanied by a seperate srt file with subtitles. Can I take the audio, video, and subtitles and just throw them into an mkv container in a single file without having to re-encode anything?

[guns1inger]

In this case, yes. If the new container can support the different encoding methods then switching containers should be quick and painless.

[jagabo]

Yes, use MkvMerge.

[gx240]

Thanks, that works well.