Does using MVKMerge on a file lower it's quality?

[NukeyDoo]

Very sorry for the newbie question, but I'm just starting out al all of this.

I have downloaded a video that has audio tracks that I don't want. Lots of them. Subs too. I had used MKVMerge (the GUI) to uncheck the ones I don't want, then let it do the muxing. The file size was dramatically reduced (which is great in my case), but I also noticed the bitrate was lower in the remuxed video, as opposed to the original.

I know the author of the original went to great pains to tweak the video/audio just right, using x265, to make it an extremely awesome quality. My concern is; by doing what I did, including the lowered bitrate, did I also lower the actual viewing quality of the video now?

Thanks for helping out a noob!

[ndjamena]

The current MediaInfo just guesses the bitrate of tracks in MKVs.

MKVMerge began adding tags a while ago to show the EXACT number of bits a stream is made from, but mediainfo won't implement it properly until the next version (10 days or so from now).

If you changed the number of constant bitrate streams in the file and all the tracks weren't of exactly the same length the bitrate MediaInfo will display for the video will change, simply because it was never correct in the first place.

[NukeyDoo]

Thank You for the info!

All I did was open the video in Toolnix, to the "Merge" tab, and uncheck the items I didn't want, then clicked Start Muxing. Would that change the constant bitrate streams automatically, or would I have to manually edit that somewhere else?

Also, I'm taking it by your answer, that the viewing quality didn't actually change, it was just the way MediaInfo was displaying the info? (Again, sorry for sounding like such a newbie, lol)

[Krispy Kritter]

Nothing is changed with the quality (the streams are untouched).

[NukeyDoo]

Great! Thank you so much!

[ndjamena]

The Audio streams you removed WERE the constant bitrate streams. I'm assuming AC3?

If MediaInfo was giving out a bitrate for the video then all the audio tracks MUST, by definition have been constant bitrate. If you have two variable bitrate streams in a file MediaInfo has no way of guessing how large either of the variable bitrate tracks would be, so no bitrate is shown at all.

That's what the tags are for.

This is the latest MediaInfo dll:

http://www.mediafire.com/download/5y4o9xucw6eizhl/MediaInfo.zip

if you copy the appropriate dlls to your MediaInfo directory, mediainfo will read the tags properly and you'll see the file exactly how it is (assuming you haven't removed the tags).

On 64 bit windows you copy MediaInfo_i386.dll from x86 and MediaInfo.dll from x64 into the "C:\Program Files\MediaInfo" directory. In 32 bit I assume you'd take MediaInfo.dll from x86 and put it in "C:\Program Files\MediaInfo".

YMMV.

[sneaker]

The Audio streams you removed WERE the constant bitrate streams. I'm assuming AC3?

If MediaInfo was giving out a bitrate for the video then all the audio tracks MUST, by definition have been constant bitrate. If you have two variable bitrate streams in a file MediaInfo has no way of guessing how large either of the variable bitrate tracks would be, so no bitrate is shown at all.

MediaInfo might also use x264's custom SEI if --bitrate was used. (Similar to how it will use the mkv statistic tags)

But: you're assuming OP is looking at the bitrate of the video track when he may as well simply be looking at the overall bitrate of the file which of course gets reduced when you remove tracks. Removing tracks = removing bits = reducing bitrate. File size and bitrate are linearly connected. (File size = bitrate * duration. And duration never changes when removing a track, a 90 minute movie will still be 90 minutes long.)

[ndjamena]

Very sorry for the newbie question, but I'm just starting out al all of this.

I have downloaded a video that has audio tracks that I don't want. Lots of them. Subs too... The file size was dramatically reduced (which is great in my case), but I also noticed the bitrate was lower in the remuxed video, as opposed to the original.

"remuxed video"...

The subtitle tracks take up bitrate too, but since they're variable bitrate mediainfo can't know how much. Assuming it just ignores them, every time you remove one the only variable bitrate stream left (ie the video) will take a hit to it's guessed bitrate.

[ndjamena]

It would have to be the subtitles then.

Longer or shorter, if you remove a constant bitrate stream from a file the variable bitrate stream always get allocated a higher bitrate.