bitrate vs file size

[satstarter]

Oke i am new here and i have a question
i dont want to discuss about video quality everybody have is own opinion
but i have a mkv video in hevc and the media info shows me bitrate is about 6 a 7 mb
the resolution is 1080p audio is eac3 5.1 the file size is about 3 a 400 mb
now how can you achief this such a big bitrate by such a small file size
i use staxrip by the way

thanx in advance

[Alwyn]

The critical missing parameter is length. How long is your video?

[satstarter]

hi the lenght is around 40 minutes
a normal lenght for a episode of a tv show

[jagabo]

First of all, don't count on MediaInfo's reported bitrate being correct. It just reports what's in the header and anybody can put whatever they want there. Often it's the maximum bitrate not the average.

The definition of average bitrate is:

bitrate = stream size / running time

with stream size in bits and running time in seconds. Simple algebraic manipulation gives:

bitrate * running time = stream size

If your video doesn't match that then the reported bitrate is simply wrong.

[DB83]

Indeed. You should look at the file-reported run-length and not the true run-length.

I have some live recordings that, due to whatever, the reported run-length was significantly larger than what it actually was.


Mediainfo simply takes the reported run-length and calculates the bitrate from the reported file-size using the above formula.


If the declared bitrate was correct AND the reported run-length, then you would have a file of approaching 2 gb. So, as you already realised, something is not right.

[Alwyn]

You should look at the file-reported run-length and not the true run-length.

Other way round.

[satstarter]

Wow this is to technical for me hahaha
I have the video from the internet
and media info says run time is 40 min 57s
total bitrate 1 188 kb/s
video runtime 40 min 57s
bitrate 6 940 kb/s
1920 x 1080
16:9
stream size 1.99 GIB

and the file size is 348 MB

[jagabo]

Once again, MediaInfo reports are not definitive.

[satstarter]

yes that i understand and i believe you
also thanx for the reply's
but it is strange because the most files give me indeed the right outcome
only this whole season gives me this info so i tought that there was a way to convert video's
with huge bitrate and low file size because normaly the standard bitrate for 1080p is 8MB (that's what i read)
and 5MB for 720p so when i try to convert something the file sizes or bigger thats why i asked about it
thanx every one

[rgr]

Wow this is to technical for me hahaha
I have the video from the internet
and media info says run time is 40 min 57s
total bitrate 1 188 kb/s
video runtime 40 min 57s
bitrate 6 940 kb/s
1920 x 1080
16:9
stream size 1.99 GIB

and the file size is 348 MB

Total bitrate seems ok. It's average bitrate.
Bitrate is MAXIMUM bitrate, not average.
Stream size is wrong.

[DB83]

** And good luck to you in watching a 1080p video that is 1,188 kb/s (unless there is no motion)

If the OP is still here, I would suggest he tries to upload the video direct here as an attachment (max size = 500 mb). Failure would suggest that reported acutal file size is closer to 1.99 gb than 348 mb)


I have recorded live-sreams that have wildly incorrectly reported either the file-size or the run-length.


And we also require confirmation that the actual run-length is 40 mins.

[rrats]

1080p bitrate should at least be 8000kbps

[satstarter]

ok file is here as atachement

[satstarter]

1080p bitrate should at least be 8000kbps

Yes i know and 720p should be 5000kbps
thats why i was suprised to see the bitrate and file size in the atached file

[DB83]

Amazing !

But it has probably benefited for a good digital source to start with (and video bitrate is a massive 909 kbps )


Look carefully at the mediainfo report and you will see all the various x265 encoder settings. Good luck !!

[jagabo]

ok file is here as atachement

When remuxed with ffmpeg the true average bitrate is calculated and stored in the MKV header:

General
Unique ID                                : 8444236453666534633318493335709255722 (0x65A4D00342E7D7EA93600BE044B882A)
Complete name                            : D:\remux.mkv
Format                                   : Matroska
Format version                           : Version 4
File size                                : 348 MiB
Duration                                 : 40 min 57 s
Overall bit rate                         : 1 188 kb/s
Writing application                      : Lavf59.16.100
Writing library                          : Lavf59.16.100
ErrorDetectionType                       : Per level 1

Video
ID                                       : 1
Format                                   : HEVC
Format/Info                              : High Efficiency Video Coding
Format profile                           : Main 10@L4@Main
Codec ID                                 : V_MPEGH/ISO/HEVC
Duration                                 : 40 min 57 s
Bit rate                                 : 909 kb/s
Width                                    : 1 920 pixels
Height                                   : 1 080 pixels
Display aspect ratio                     : 16:9
Frame rate mode                          : Constant
Frame rate                               : 23.976 (24000/1001) FPS
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 10 bits
Bits/(Pixel*Frame)                       : 0.018
Stream size                              : 266 MiB (76%)
Writing library                          : x265 3.5+9-bf91444e0:[Windows][GCC 10.2.0][64 bit] 10bit
Encoding settings                        : cpuid=1111039 / frame-threads=3 / numa-pools=12 / wpp / no-pmode / no-pme / no-psnr / no-ssim / log-level=2 / input-csp=1 / input-res=1920x1080 / interlace=0 / total-frames=0 / level-idc=0 / high-tier=1 / uhd-bd=0 / ref=1 / no-allow-non-conformance / no-repeat-headers / annexb / no-aud / no-eob / no-eos / no-hrd / info / hash=0 / no-temporal-layers / open-gop / min-keyint=23 / keyint=250 / gop-lookahead=0 / bframes=3 / b-adapt=0 / b-pyramid / bframe-bias=0 / rc-lookahead=5 / lookahead-slices=6 / scenecut=0 / hist-scenecut=0 / radl=0 / no-splice / no-intra-refresh / ctu=32 / min-cu-size=16 / no-rect / no-amp / max-tu-size=32 / tu-inter-depth=1 / tu-intra-depth=1 / limit-tu=0 / rdoq-level=0 / dynamic-rd=0.00 / no-ssim-rd / no-signhide / no-tskip / nr-intra=0 / nr-inter=0 / no-constrained-intra / strong-intra-smoothing / max-merge=2 / limit-refs=0 / no-limit-modes / me=0 / subme=0 / merange=57 / temporal-mvp / no-frame-dup / no-hme / no-weightp / no-weightb / no-analyze-src-pics / deblock=0:0 / no-sao / no-sao-non-deblock / rd=2 / selective-sao=0 / early-skip / rskip / fast-intra / no-tskip-fast / no-cu-lossless / no-b-intra / no-splitrd-skip / rdpenalty=0 / psy-rd=2.00 / psy-rdoq=0.00 / no-rd-refine / no-lossless / cbqpoffs=0 / crqpoffs=0 / rc=crf / crf=23.0 / qcomp=0.60 / qpstep=4 / stats-write=0 / stats-read=0 / ipratio=1.40 / pbratio=1.30 / aq-mode=1 / aq-strength=0.00 / cutree / zone-count=0 / no-strict-cbr / qg-size=32 / no-rc-grain / qpmax=69 / qpmin=0 / no-const-vbv / sar=1 / overscan=0 / videoformat=5 / range=0 / colorprim=1 / transfer=1 / colormatrix=1 / chromaloc=0 / display-window=0 / cll=0,0 / min-luma=0 / max-luma=1023 / log2-max-poc-lsb=8 / vui-timing-info / vui-hrd-info / slices=1 / no-opt-qp-pps / no-opt-ref-list-length-pps / no-multi-pass-opt-rps / scenecut-bias=0.05 / hist-threshold=0.03 / no-opt-cu-delta-qp / no-aq-motion / no-hdr10 / no-hdr10-opt / no-dhdr10-opt / no-idr-recovery-sei / analysis-reuse-level=0 / analysis-save-reuse-level=0 / analysis-load-reuse-level=0 / scale-factor=0 / refine-intra=0 / refine-inter=0 / refine-mv=1 / refine-ctu-distortion=0 / no-limit-sao / ctu-info=0 / no-lowpass-dct / refine-analysis-type=0 / copy-pic=1 / max-ausize-factor=1.0 / no-dynamic-refine / no-single-sei / no-hevc-aq / no-svt / no-field / qp-adaptation-range=1.00 / scenecut-aware-qp=0conformance-window-offsets / right=0 / bottom=0 / decoder-max-rate=0 / no-vbv-live-multi-pass
Language                                 : English
Default                                  : Yes
Forced                                   : No
Color range                              : Limited
Color primaries                          : BT.709
Transfer characteristics                 : BT.709
Matrix coefficients                      : BT.709
VENDOR_ID                                : [0][0][0][0]

Audio
ID                                       : 2
Format                                   : E-AC-3
Format/Info                              : Enhanced AC-3
Commercial name                          : Dolby Digital Plus
Codec ID                                 : A_EAC3
Duration                                 : 40 min 57 s
Bit rate mode                            : Constant
Bit rate                                 : 256 kb/s
Channel(s)                               : 6 channels
Channel layout                           : L R C LFE Ls Rs
Sampling rate                            : 48.0 kHz
Frame rate                               : 31.250 FPS (1536 SPF)
Bit depth                                : 32 bits
Compression mode                         : Lossy
Stream size                              : 75.0 MiB (22%)
Language                                 : English
Service kind                             : Complete Main
Default                                  : Yes
Forced                                   : No
VENDOR_ID                                : [0][0][0][0]

[satstarter]

i did also a copy/mux with staxrip
and indeed the bitrate gives me 929 kbps
the only thing i wonder is from where comes the 6.900 kbps in the original file
maybe someone has alterd the header info then?

then another question what do you guys think (or know) if you have a video
and let us say its 720p and 5000 kbps bitrate and you convert it with 6000 kbps will this be better or
will the quality not be better ?

[Jerome7573_3]

the only thing i wonder is from where comes the 6.900 kbps in the original file

It comes from the MKV File Statistics Tags:

0000E4C    SimpleTag (26 bytes)
0000E4C     Header (10 bytes)
0000E4C      Name:                              10184 (0x27C8)
0000E4E      Size:                              16 (0x00000000000010)
0000E56     TagName - BPS (6 bytes)
0000E56      Header (3 bytes)
0000E56       Name:                             1443 (0x05A3)
0000E58       Size:                             3 (0x03)
0000E59      Data:                              BPS
0000E5C     TagString - 6940034 (10 bytes)
0000E5C      Header (3 bytes)
0000E5C       Name:                             1159 (0x0487)
0000E5E       Size:                             7 (0x07)
0000E5F      Data:                              6940034
0000E66    SimpleTag (37 bytes)
0000E66     Header (10 bytes)
0000E66      Name:                              10184 (0x27C8)
0000E68      Size:                              27 (0x0000000000001B)
0000E70     TagName - NUMBER_OF_FRAMES (19 bytes)
0000E70      Header (3 bytes)
0000E70       Name:                             1443 (0x05A3)
0000E72       Size:                             16 (0x10)
0000E73      Data:                              NUMBER_OF_FRAMES
0000E83     TagString - 58917 (8 bytes)
0000E83      Header (3 bytes)
0000E83       Name:                             1159 (0x0487)
0000E85       Size:                             5 (0x05)
0000E86      Data:                              58917
0000E8B    SimpleTag (41 bytes)
0000E8B     Header (10 bytes)
0000E8B      Name:                              10184 (0x27C8)
0000E8D      Size:                              31 (0x0000000000001F)
0000E95     TagName - NUMBER_OF_BYTES (18 bytes)
0000E95      Header (3 bytes)
0000E95       Name:                             1443 (0x05A3)
0000E97       Size:                             15 (0x0F)
0000E98      Data:                              NUMBER_OF_BYTES
0000EA7     TagString - 2131744335 (13 bytes)
0000EA7      Header (3 bytes)
0000EA7       Name:                             1159 (0x0487)
0000EA9       Size:                             10 (0x0A)
0000EAA      Data:                              2131744335

Bad input (stats seem wrong, file seems complete with ~300 MB) leads to bad MediaInfo report, we currently read out such data and trust it, no coherency check is currently implemented.

Jérôme, developer of MediaInfo.

[jagabo]

then another question what do you guys think (or know) if you have a video
and let us say its 720p and 5000 kbps bitrate and you convert it with 6000 kbps will this be better or
will the quality not be better ?

It can only get worse. Reencoding with lossy codecs can only reduce the quality, even if you use more bitrate than the source.

[satstarter]

Ok thanx everyone
things are more clearly now