Video bit rate discrepancy

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opalfruit
Posts: 2
Joined: Thu May 02, 2019 6:26 pm

Video bit rate discrepancy

Post by opalfruit »

Hello, I'm looking for a bit of help I was under the assumption that makemkv makes a 1:1 copy of a file from a disc, however I have noted discrepancies between file sizes and bit rates between versions. To explain what I mean I re-ripped some files that I first ripped in 2015 using version 1.9.2 this game me a file size of 759mb for a episode from a DVD, re-ripping the file came out at 760mb for the same episode and checking Media Info shows the new rip using version 1.14.3 has a higher video bit rate. Can anyone shed any light on why this is? (apologies in advance if this has already been asked)

Media Info data as follows: 2015 rip
General
Unique ID : 38961423861423271019780600103841156105 (0x1D4FB281894E400A8C3B27EBC3E1CC09)
Complete name : H:\DVDs\TV Shows\The Nightmare Room\Season 1\s01e04 Tangled Web.mkv
Format : Matroska
Format version : Version 2
File size : 760 MiB
Duration : 20 min 29 s
Overall bit rate mode : Variable
Overall bit rate : 5 186 kb/s
Movie name : NIGHTMARE ROOM VOLUME 1
Encoded date : UTC 2015-06-11 19:52:35
Writing application : MakeMKV v1.9.2 win(x64-release)
Writing library : libmakemkv v1.9.2 (1.3.0/1.4.1) win(x64-release)

Video
ID : 1
Format : MPEG Video
Format version : Version 2
Format profile : Main@Main
Format settings : CustomMatrix / BVOP
Format settings, BVOP : Yes
Format settings, Matrix : Custom
Format settings, GOP : M=3, N=15
Format settings, picture structure : Frame
Codec ID : V_MPEG2
Codec ID/Info : MPEG 1 or 2 Video
Duration : 20 min 29 s
Bit rate mode : Variable
Bit rate : 4 891 kb/s
Maximum bit rate : 7 500 kb/s
Width : 720 pixels
Height : 480 pixels
Display aspect ratio : 4:3
Frame rate mode : Constant
Frame rate : 29.970 (30000/1001) FPS
Standard : NTSC
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Interlaced
Scan order : Top Field First
Compression mode : Lossy
Bits/(Pixel*Frame) : 0.472
Time code of first frame : 00:59:58:00
Time code source : Group of pictures header
GOP, Open/Closed : Open
GOP, Open/Closed of first frame : Closed
Stream size : 717 MiB (94%)
Language : English
Default : No
Forced : No

Audio
ID : 2
Format : AC-3
Format/Info : Audio Coding 3
Commercial name : Dolby Digital
Codec ID : A_AC3
Duration : 20 min 29 s
Bit rate mode : Constant
Bit rate : 192 kb/s
Channel(s) : 2 channels
Channel layout : L R
Sampling rate : 48.0 kHz
Frame rate : 31.250 FPS (1536 SPF)
Bit depth : 16 bits
Compression mode : Lossy
Stream size : 28.1 MiB (4%)
Title : Stereo
Language : English
Service kind : Complete Main
Default : Yes
Forced : No

2019 rip

General
Unique ID : 297002538029485553587378184950306131667 (0xDF709BB00BC9C1DE578DE69AED514ED3)
Complete name : H:\DVDs\TV Shows\The Nightmare Room\The Nightmare Room - 104 - Tangled Web.mkv
Format : Matroska
Format version : Version 2
File size : 760 MiB
Duration : 20 min 29 s
Overall bit rate mode : Variable
Overall bit rate : 5 190 kb/s
Movie name : NIGHTMARE ROOM VOLUME 1
Encoded date : UTC 2019-05-02 18:14:09
Writing application : MakeMKV v1.14.3 win(x64-release)
Writing library : libmakemkv v1.14.3 (1.3.5/1.4.7) win(x64-release)

Video
ID : 1
ID in the original source medium : 224 (0xE0)
Format : MPEG Video
Format version : Version 2
Format profile : Main@Main
Format settings : CustomMatrix / BVOP
Format settings, BVOP : Yes
Format settings, Matrix : Custom
Format settings, GOP : M=3, N=15
Format settings, picture structure : Frame
Codec ID : V_MPEG2
Codec ID/Info : MPEG 1 or 2 Video
Duration : 20 min 29 s
Bit rate mode : Variable
Bit rate : 4 988 kb/s
Maximum bit rate : 7 500 kb/s
Width : 720 pixels
Height : 480 pixels
Display aspect ratio : 4:3
Frame rate mode : Constant
Frame rate : 29.970 (30000/1001) FPS
Standard : NTSC
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Interlaced
Scan order : Top Field First
Compression mode : Lossy
Bits/(Pixel*Frame) : 0.482
Time code of first frame : 00:59:58:00
Time code source : Group of pictures header
GOP, Open/Closed : Open
GOP, Open/Closed of first frame : Closed
Stream size : 731 MiB (96%)
Language : English
Default : No
Forced : No
Original source medium : DVD-Video

Audio
ID : 2
ID in the original source medium : 189 (0xBD)128 (0x80)
Format : AC-3
Format/Info : Audio Coding 3
Commercial name : Dolby Digital
Codec ID : A_AC3
Duration : 20 min 29 s
Bit rate mode : Constant
Bit rate : 192 kb/s
Channel(s) : 2 channels
Channel layout : L R
Sampling rate : 48.0 kHz
Frame rate : 31.250 FPS (1536 SPF)
Bit depth : 16 bits
Compression mode : Lossy
Stream size : 28.1 MiB (4%)
Title : Stereo
Language : English
Service kind : Complete Main
Default : Yes
Forced : No
Original source medium : DVD-Video

Text #1
ID : 3
ID in the original source medium : 189 (0xBD)32 (0x20)
Format : VobSub
Codec ID : S_VOBSUB
Codec ID/Info : Picture based subtitle format used on DVDs
Duration : 19 min 54 s
Bit rate : 3 779 b/s
Count of elements : 259
Stream size : 551 KiB (0%)
Language : English
Default : Yes
Forced : No
Original source medium : DVD-Video

Text #2
ID : 4
ID in the original source medium : 224 (0xE0)
Format : UTF-8
Codec ID : S_TEXT/UTF8
Codec ID/Info : UTF-8 Plain Text
Duration : 19 min 51 s
Bit rate : 125 b/s
Count of elements : 368
Stream size : 18.2 KiB (0%)
Language : English
Default : No
Forced : No
Original source medium : DVD-Video
opalfruit
Posts: 2
Joined: Thu May 02, 2019 6:26 pm

Re: Video bit rate discrepancy

Post by opalfruit »

Just realized it's likely cause one file has subs... file a bit daft now thread can be closed.
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