Reduced video size after muxing with mkvmerge

[sazolis]

Hi!

I used mkvmerge to delete an audio track from an mkv file. However, the video size was also reduced from 58.2 GiB to 53.1 GiB. The audio track was 2.41 GiB. The total file size was reduced from 73.6 to 66 GiB. So clearly there is a bitrate loss.

The compression in the Extra Options tab was set to ''none''. Does anybody have any idea why is this happening? Mkvmerge should not encode the video...

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4.1
Format settings, CABAC : Yes
Format settings, ReFrames : 2 frames
Format settings, GOP : M=1, N=10
Codec ID : V_MPEG4/ISO/AVC
Duration : 3h 48mn
Bit rate mode : Variable
Bit rate : 36.5 Mbps -> 33.3 Mbps
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 23.976 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.670
Stream size : 58.2 GiB -> 53.1 GiB (80%)
Title : Video (29853 kbps)
Language : English
Default : Yes
Forced : No

[Baldrick]

Can you play the entire video without problems?

[sazolis]

Yes, the video can be played without problems. And because of the high bitrate I can not really distinguish between the quality of the two streams. So it is strange...

[Baldrick]

mkvmerge can not convert so you can't lose any video quality. But mkvmerge might have stripped/cutted a part of the video. Or it's just a big mkv overhead.

How did you make the original mkv? With makemkv or something else?

[sazolis]

Yes, the video was made with makemkv.

Actually, I will have to check indeed if there is any part that has been cut. So far I just jumped to various locations in the mkv. Is there any tool that compares two videos?

[Selur]

1. wouldn't it be easier to simply to a detailed mediainfo analysis on both files,...
2. don't trust the audio/video bitrates MediaInfo posts
my bet would be that there's not something fishy going on, but you either left something else out when remuxing or your audio was larger

[sazolis]

Thanks for the tips. I will try to remux and take out only a subtitle. Then the file size should be almost the same...