Why are lossless video files so large?

[Guernsey]

I had been upscaling my videos in Virtualdub2 using the lossless codec called Lagarith Lossless but they always seem to end as being hilariously large files. Can anyone explain this? Why do lossless files always end being large?

[poisondeathray]

Lagarith is lossless compared to the uncompressed version. That uncompressed version is going to be about 2x larger than the lagarith file.

On most scenarios, you can get slightly better compression ratios by using lossless temporal compression. Lagarith is intraframe only (with the exception of null frames cases) . But ffv1, x264 in lossless mode can be set to utilize temporal compression

[krykmoon]

I can't see the sense in questions like this.

It's like asking: why if I should carry 1000 clothes I need a luggage bigger than the one I would need carrying only 10 (or 1) ? The answer is : because they take a lot of much more space. A lossless codec store ALL of the original data/information and doesn't remove anything from it. That's exactly what a lossless codec does: retain EVERYTHING. So.. you keep all 1000 clothes in your suitcase.. not only 10 (or 1) like with lossy. That's why you need a bigger suitcase. There's really nothing to understand.

[Alwyn]

My understanding is this. Take 5 frames of video. A lossy codec such as H264 would look at the second frame and say "the only part that has changed from the first frame is the small movement at the top right, so I'll only store that change", and so on. Only the changed bits of the next frame are stored (at regular intervals, though, a full frame is saved). This means the file size can be drastically reduced compared to... Lossless or uncompressed, where each frame, in it's entirety, is saved. That's why lossless files are so much larger than lossy files. Lossless, though, is much better for editing because you're not relying on the editor trying to work out what the following frames should be after you've made an edit and you don't lose data/quality when you re-save.

And when you're upscaling, doubling the size/resolution increases the number of pixels by 4 times.

I think that's why...

[netmask56]

Lossless is a close approximation to the actual real size - non lossless formats are by definition inferior as they have removed portions of the original data considered redundant, hence loss of quality but a smaller file.

[Cornucopia]

My understanding is this. Take 5 frames of video. A lossy codec such as H264 would look at the second frame and say "the only part that has changed from the first frame is the small movement at the top right, so I'll only store that change", and so on. Only the changed bits of the next frame are stored (at regular intervals, though, a full frame is saved). This means the file size can be drastically reduced compared to... Lossless or uncompressed, where each frame, in it's entirety, is saved. That's why lossless files are so much larger than lossy files. Lossless, though, is much better for editing because you're not relying on the editor trying to work out what the following frames should be after you've made an edit and you don't lose data/quality when you re-save.

And when you're upscaling, doubling the size/resolution increases the number of pixels by 4 times.

I think that's why...

@Alwyn, you are confounding "LossLess vs Lossy" with "Intra-Frame vs inter-Frame (x-Frame)" compression. And yes, it is possible to have LL/IF, LL/xF, Ly/IF, and Ly/xF types, even though most often one sees LL combined with IF and Ly combined with xF.
e.g. AVC-Intra is Ly/IF, while x264 in lossless mode can still be Inter aka LL/xF, if you set the settings right.

Lossy is smaller/more efficient than lossless because it throws away valid possibly needed data. Or "quantization error residuals". Aka losing quality. A la @netmask56's "approximation".

Interframe is smaller/more efficient than intraframe for the reason you mentioned above - saving only interframe differences (usually motion, but also noise, edits...). So only partial pictures, and/or motion vectors, and/or placeholders.


Scott

[Guernsey]

What would be a good way to reduce the file size while still keeping the quality? I really do not want to older stuff like XVID but I need to do something to reduce the file size.

[davexnet]

What would be a good way to reduce the file size while still keeping the quality? I really do not want to older stuff like XVID but I need to do something to reduce the file size.

Use x264, 8-bit, preset Slow, CRF (quality factor) 16. Can do this easily in Vdub2. Save file as mp4 or mkv

[Guernsey]

Does that method for animation, gaming, etc.?

[davexnet]

Why don't you do some test encodes, comparing the Lagarith to my proposal above?

[Guernsey]

I did the encodes and it looks like I was able to save some space. Does the preset effect how end video is going to be? And does it really matter if the codec is x264 8-Bit/10-Bit?

[davexnet]

The presets give different/more methods of optimizing the videos, reflected in the respective encode speed. You can try "faster" or "medium" as an alternative. You may not see a difference.

10 bit better preserves fine gradations of tone/color, assuming this detail exists in your source

[Guernsey]

General
Complete name                            : ***********.avi
Format                                   : AVI
Format/Info                              : Audio Video Interleave
File size                                : 1.84 GiB
Duration                                 : 4 min 46 s
Overall bit rate                         : 55.1 Mb/s
Writing library                          : VirtualDub2 build 44282/release

Video
ID                                       : 0
Format                                   : Lagarith
Codec ID                                 : LAGS
Duration                                 : 4 min 46 s
Bit rate                                 : 53.7 Mb/s
Width                                    : 960 pixels
Height                                   : 720 pixels
Display aspect ratio                     : 4:3
Frame rate                               : 60.000 FPS
Color space                              : Y
Bits/(Pixel*Frame)                       : 1.294
Stream size                              : 1.79 GiB (97%)

Audio
ID                                       : 1
Format                                   : PCM
Format settings                          : Little / Signed
Codec ID                                 : 1
Duration                                 : 4 min 46 s
Bit rate mode                            : Constant
Bit rate                                 : 1 411.2 kb/s
Channel(s)                               : 2 channels
Sampling rate                            : 44.1 kHz
Bit depth                                : 16 bits
Stream size                              : 48.1 MiB (3%)
Alignment                                : Aligned on interleaves
Interleave, duration                     : 17  ms (1.00 video frame)
Interleave, preload duration             : 500  ms

Complete name                            :************.mkv
Format                                   : Matroska
Format version                           : Version 4
File size                                : 177 MiB
Duration                                 : 4 min 46 s
Overall bit rate                         : 5 177 kb/s
Writing application                      : Lavf57.79.100
Writing library                          : Lavf57.79.100
ErrorDetectionType                       : Per level 1

Video
ID                                       : 1
Format                                   : AVC
Format/Info                              : Advanced Video Codec
Format profile                           : High@L3.2
Format settings                          : CABAC / 5 Ref Frames
Format settings, CABAC                   : Yes
Format settings, Reference frames        : 5 frames
Codec ID                                 : V_MPEG4/ISO/AVC
Duration                                 : 4 min 46 s
Bit rate                                 : 3 663 kb/s
Width                                    : 960 pixels
Height                                   : 720 pixels
Display aspect ratio                     : 4:3
Frame rate mode                          : Constant
Frame rate                               : 60.000 FPS
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Progressive
Bits/(Pixel*Frame)                       : 0.088
Stream size                              : 125 MiB (71%)
Writing library                          : x264 core 157 r2935M 545de2f
Encoding settings                        : cabac=1 / ref=5 / deblock=1:0:0 / analyse=0x3:0x113 / me=hex / subme=8 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=2 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=12 / lookahead_threads=2 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3 / b_pyramid=2 / b_adapt=1 / b_bias=0 / direct=3 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc_lookahead=50 / rc=crf / mbtree=1 / crf=16.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / ip_ratio=1.40 / aq=1:1.00
Default                                  : Yes
Forced                                   : No
Color range                              : Limited
Matrix coefficients                      : BT.470 System B/G

Audio
ID                                       : 2
Format                                   : PCM
Format settings                          : Little / Signed
Codec ID                                 : A_PCM/INT/LIT
Duration                                 : 4 min 46 s
Bit rate mode                            : Constant
Bit rate                                 : 1 411.2 kb/s
Channel(s)                               : 2 channels
Sampling rate                            : 44.1 kHz
Bit depth                                : 16 bits
Stream size                              : 48.1 MiB (27%)
Default                                  : Yes
Forced                                   : No

Here are results I got with a video and I used a newer version of the Mediainfo to get this information. I cannot export the upscaled files to mp4 in Virtualdub2 so I used mkv for the other one and I wonder if I am better off using something like VidCoder or something?

[davexnet]

mp4 may be disallowed because of the uncompressed audio. To compress the audio select

Audio/full processing mode
Audio/compression (choose FFmpeg/aac )

Now mp4 should be available.

What are you trying to achieve, exactly?

[Guernsey]

I just want good compression with low disk space that is all. I was looking for something that doesn't go beyond 2GB just for a 10 min video when I upscale it.