A lot of passes have been done...

I remember in 1993-95, to compress in AVI with Radius Cinepack codec or the Intel Indeo 3.2 compressors from a PAL signal precropped to CIF format (352x288 pixels) , running on a 486 or one of the first pentium based PC's (the maximum available at the time), required an entire day (23 hours). After all the output quality was very poor if compared to today's codecs. The audio has been compressed in linear PCM with a sampling rate of 11025 KHz because at that time mpeg 1 layer 2 -- despite at that time it would be already available -- was correctly played only by dedicated hardware.

If you want you may download to play a small video (the "credits", the people that worked on Multimedia 2 go), 2 minutes long I've found on the original CD we made, compressed in Intel Indeo 3.2 (19.6 MB), in current h264 with mp3 audio (about 3.2 MB) and current h264 with aac audio (about 2.4 MB).
Expecially the first version, a quite big file, compressed with a very old codec, could be reproduced only by VLC (despite it should be playable by default by Windows), and in any case could be good to download it before through the right mouse click and "save as".
When I tested this page, I remained quite surprised to see that the entire 2 minute video, compressed in h264, was played immediately by mozilla firefox, not - as I though - through VLC after it had been choosed as default opener of mp4 files. Evidently the browser itself in a way similar to what required by HTML5 compliancy, can decode those file (they are not stream, but file seen in progressive download).
It is all but a curious note. Html5 compliancy is a big problem, as it has been interpreted by Google Chrome: the management of video compressions cannot be performedthrough external plug-ins, but must be performed by the browser itself.
Mobile phones' browsers do not use plug-ins while workstations ones allow them. But the new releases of Chrome don't accept VLC plug-in as dangerous for navigation safety.

Comparisons between the three version of the same video (mediainfo)
Filename H:\video\Multimedia 2 Go people (19950222).avi
(not downloadable because seen unsafe by many browsers)
H:\video\Multimedia 2 Go people (19950222)_a.mp4H:\video\Multimedia 2 Go people (19950222)_d.mp4
FormatAVI, Audio Video Interleave, recMPEG-4, Base Media, isomMPEG-4, Base Media, isom
File size19.1 MiB3.16 MiB2.38 MiB
Duration2mn 7s2mn 7s2mn 7s
Overall bit rate1 257 Kbps208 Kbps157 Kbps
Format, Codec, Version/Profile/LevelIndeo 3, IV32, Intel Indeo Video 3.2AVC, Advanced Video Coding, High@L1.3AVC, Advanced Video Coding, High@L1.3
DetailsCABAC, Reframes=4CABAC, Reframes=4
Width, Display Aspect Ratio, Frame Rate320x240, 4:3, 25 fps320x240, 4:3, 25 fps320x240, 4:3, 25 fps
Frame Rate25 fpsvariable: mean 24.247 fps, min 6.250 fps, max 25.000 fpsvariable: mean 24.247 fps, min 6.250 fps, max 25.000 fps
Color space, Chroma subsampling, Bit Depth, ScanY'UV, 4:2:0, ProgressiveYUV, 4:2:0, 8bit, ProgressiveYUV, 4:2:0, 8bit, Progressive
Stream size16.8 MiB (88%)2.22 MiB (70%)1.48 MiB (62%)
Writing Libraryx264 core 146 r2538 121396cx264 core 146 r2538 121396c
Detailscabac=1, ref=3, deblock=1:0:0, analyse=0x3:0x133, me=hex, subme=7, psy=1, psy_rd=1.00:0.00, mixed_ref=1, me_range=16, chroma_me=1, trellis=1, 8x8dct=1, cqm=0, deadzone=21,11, fast_pskip=1, chroma_qp_offset=-2, threads=3, lookahead_threads=1, 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=1, weightb=1, open_gop=0, weightp=2, keyint=250, keyint_min=25, scenecut=40, intra_refresh=0, rc_lookahead=40, rc=2pass, mbtree=1, bitrate=150, ratetol=1.0, qcomp=0.60, qpmin=10, qpmax=51, qpstep=4, cplxblur=20.0, qblur=0.5, ip_ratio=1.40, aq=1:1.00
Format, Endianness, Sign, Codec IDPCM, Little, Unsigned, 1MPEG Audio, Version 1, Layer 3, 6BAAC (lav), Advanced Audio Codec LC, 40
Bitrate88.2 Kbps56.0 Kbps50.8 Kbps (max 56 Kbps)
Bitrate mode, Sampling rate, channelsConstant, 11.025 KHz, 1 channelConstant, 48.0 KHz, 2 channelsConstant, 48.0 KHz, 2 channels
Alignement, interleave durationAligned on interleaves, 40 ms (1.00 video frame)
Stream Size1.34 MiB (7%)872 KiB (27%)791 KiB (32%)