8 mm video format
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8mm video format (official names: Video8, later Hi8 and finally Digital8) is an analog (Video8 and Hi8) or digital (Digital8) video recording format for the NTSC and PAL/SECAM television systems. In 1985, Sony of Japan introduced the Handycam, one of the first Video8 cameras. Much smaller than the competition's VHS and Betamax video cameras, Video8 became very popular in the consumer camcorder market.
The Video8 format later saw various improvements including higher resolution (renamed Hi8), digital stereo PCM sound (for some professional grade equipment) and finally the move to digital (renamed Digital8). Its user base consisted mainly of amateurs but also saw important use in the professional field.
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Overview
Like other consumer-video systems of the 1980s, Video8 uses a helical-scan head-drum to read/write video to the recording media (magnetic tape.) The drum rotates at high-speed (1800 or 3600rpm) while the tape is pulled along the drum's path. Because the tape and drum are oriented at a slight angular offset, the recording tracks are laid down as diagonally horizontal stripes. The recordings are analog in the case of Video8 and Hi8 (although on Hi8 some professional equipment can also record digital stereo PCM sound in parallel with the analog sound, on a special track reserved for this purpose). This is in direct contrast to the DAT system (digital audio tape), which uses similar media, but a different head/tape orientation (perpendicular) and additional digital-coding with the recording-modulation.
The 8mm magnetic tape is wound between two spools, held in a hard-shelled cassette. Video8 cassettes share similar size and appearance with the audiocassette, but mechanical operation is much closer to the VHS/Betamax videocassette. Video8 cassettes come with a standard recording time of up to 90 minutes for PAL and 120 minutes for NTSC. (The cassette holds the same length tape -- tape-consumption is different between PAL and NTSC recorders.)
Since 8mm competed in a market formerly dominated by Betamax and VHS, it is worthwhile to compare the audio/video qualities of all 3 formats. Unfortunately, an objective comparison is complicated by the fact that the formats did not stand still, rather they evolved over time. As backers of one format introduced an improvement, the competition would respond by improvements of its own, and so on. For purposes of discussion, it is convenient to divide the comparison into two periods of interest: the first-generation (VHS, Beta, Video8), and the second-generation (SVHS, ED Beta, Hi8.) And furthermore, the comparison is restricted purely to consumer camcorders, that is, acquisition equipment. Non-portable (settop) and editing equipment fall under a different category.
In the first-generation, Video8 entered a camcorder market dominated by VHS and Betamax. Video8's video-performance was a mixed bag, outperforming the full-size formats (VHS and Betamax) in some respects but falling short in others. Betamax, traded higher tape-consumption for higher video-fidelity, at the expense of reduced recording-time (100min.) The two remaining formats, VHS and Video8, were both rated at "240 horizontal lines." In terms of recording length, VHS and Video8 once again tied, with recording-times of (120minutes.)
By the mid-1980s, the Betamax format had advanced to SuperBeta (higher luminance carrier), while VHS had added HQ circuitry. Once again, SuperBeta took the picture-quality lead (at ~300 lines of resolution.) During this time, Video8 did not receive any format upgrades. Yet the difference between VHS HQ and Video8 is minimal at best, and not significant to the untrained eye. The addition of slower tape-speeds increased the recording-times available to all 3 formats (at the expense of picture quality.)
In terms of audio-quality, the comparison is once again complicated by improvements made to the various formats. Further clarification is necessary. In the VHS and Betamax formats, the standard audiotrack is recorded on a narrow linear track along the edge of the tape, where they are especially vulnerable to tape-damage. Due to this arrangement, Beta/VHS linear audio exhibits audio characteristics similar to a low-quality audiocassette. In Video8, the standard audiotrack is modulated onto a carrier, so that it is recorded along the same helical tape-path as the video. This technique is called audio frequency modulation (AFM.) By the time of Video8's introduction, VHS/Beta VCRs had already incorporated AFM technology, marketing it as "Hi-Fi stereo." But while VHS/Beta AFM was superior in fidelity (and always implemented in stereo), Hi-Fi stereo was a rarity on any camcorder. Camcorder microphones were very primitive at this time.
In comparing equivalently priced camcorders from all 3 formats, Video8 camcorders are equipped with an AFM audiotrack as standard. At Video8's introduction, the majority of Beta/VHS camcorders were still limited to standard (linear) audiotracks. Hi-Fi (AFM) audio did not reach Beta/VHS camcorders until much later, and were only found on the most expensive units. Stereo audio was implemented on the VHS/Beta linear audiotracks, but with a reduction in already poor sound-quality. Video8 did not have an equivalent linear audiotrack, only AFM audio (which performed between VHS/Beta linear stereo and VHS/Beta Hi-Fi.) In this light, it is safe to say that for the mass market, Video8 offered the best audio experience.
In the second-generation, the formats of interest are SVHS, ED-Beta (Extended Definition Beta), and Hi8 (Hi-Band Video8.) By this time, Betamax had lost so much marketshare in both the home-video and camcorder market, that ED-Beta ceased to have sufficient retail-market presence. So despite ED-Beta's technical superiority, it did not factor into the average consumer's decision process. SVHS and Hi8 were the only viable 2nd-gen home-video formats. Once again, SVHS and Hi8 were similar in both resolution potential (400 horizontal lines) and recording-times (120min.) Toward the late 1990s, XR extended-resolution technology was introduced for both the Video8 and Hi8, but brought barely noticeable improvement.
In terms of audio, Hi-Fi stereo was still limited to high-end camcorders. VHS/Beta Hi-Fi already performed near CD-quality, outperforming Video8 AFM in all performance metrics (S/N ratio, flat frequency-response, and stereo channel-separation.) SVHS retained the same linear-audio tracks and AFM audio-system as VHS, meaning that SVHS recordings possessed up to two independent soundtracks (linear and Hi-Fi.) SVHS also retained VHS's linear-audio "dubbing" ability -- which enabled audio to be re-recorded without disturbing the underlying-video. In actual use, camcorder sound-quality was limited by the built-in microphones. and unless studio-quality external-mics were deployed with VHS Hi-Fi, there was little practical difference between Video8 AFM stereo and VHS Hi-Fi stereo.
In both generations, Video8's smaller head-drum leaves Video8 recorders more susceptible to 'tape-dropout.' All magnetic video-recorders suffer from dropouts. Dropouts are caused by the erosion of magnetic-particles from the media surface. As the audio/video signal is held in a smaller area on a Video8 tape, a dropout affects a greater portion of the recorded-signal. Hence, dropout compensation in Video8 systems tend to be more advanced to mitigate the format's vulnerability to dropouts. In this respect, VHS and Betamax's larger head-drums prove advantageous.
PCM-audio was added to both VHS and 8mm formats. In 8mm and Hi8, the PCM-audio was recorded at a sample-rate of 32 kHz, compared to VHS PCM at 44.1 kHz. Once again, VHS/SVHS offered the better experience.
(Edit note, new contributor, HI-FI VHS-SVHS will automatically have a redundant back up linear channel, Digital-8 apparently does not, making the audio susceptible to not coming out even if the picture is still viewable. This doesn't happen regularly, but if it does happen, you have for all intents and purposes lost your audio, whereas with VHS or S-VHS, one of either the stereo Hi-FI or linear tracks should work even if there is a recording problem.)
Camcorders
In its originally intended role as a portable video camera, Video8 excelled. Thanks to their compact-form factor, Video8 camcorders were small enough to hold in the palm of the user's hand. Such a feat was not possible with full-sized Betamax and VHS camcorders, which operated best on sturdy tripods or strong shoulders. And even though the full-sized recorders held the advantage in recording-time (100+ minutes per cassette), Video8's 60-minute capacity served well for most users. Longer sessions generally required other infrastructure to be present (additional batteries or AC power), and hence longer recording-times offered little advantage in a true travelling environment.
Video8/Hi8's drawback was incompatibility with VHS equipment; tapes made with Video8 hardware could not be directly played on VHS hardware (and vice versa). This problem could be overcome by "dubbing" the video; using the VCR to make a copy of the original video as it was played by the camcorder, although this (as with all analog formats) had the drawback of degrading the copied-signal.
The VHS-C format attempted to capitalize on the hardware incompatibility between VHS and Video8. VHS-C and VHS share the same 1/2" magnetic-media, but VHS-C stores the tape in smaller cassettes. This limits VHS-C to 20 minutes of (SP) recording-time. To mitigate short endurance of VHS-C camcorders, all VHS-C camcorders offered LP and EP recording-speeds (but with severely compromised picture-quality as a consequence). VHS-C maintains compatibility with VHS by sharing the same recording-system and format. A mechanical adapter allows the small VHS-C cassette to be inserted (and used) by full-size VHS equipment.
Efforts were made to expand Video8 from the camcorder market into mainstream home-video. But as a replacement for fullsize VCRs, Video8 failed. It lacked the long (5+ hour) recording-time of both VHS and Betamax, offered no clear audio/video improvement, and cost more than fullsize VCRs. Quite simply, Video8 was not convincing in the home-VCR application. The rental-market for Video8 never materialized, though Sony maintained a line of Video8 home-VCRs well into the 1990s.
Among home and amateur videographers Video8/Hi8 was quite popular, popular enough for Sony to make equipment for video-editing and production. The format also saw some use in the professional ENG/EFP field.
As of 2005, analog video recording is being supplanted by digital video recording. In the consumer market, the analog formats have given way to digital formats (such as Digital8 and miniDV).
Enhancements to Video8
The format-wars in the home-VCR market led to a rapid pace of development in the camcorder market. VHS, Betamax, and Video8 had all launched with one recording-speed (120 minutes for NTSC VHS and Video8, 100 minutes for NTSC Betamax.) By the time of Video8's introduction, Betamax and VHS had doubled their original recording-times through the addition of a 'Long-Play' (LP) mode. Video8 later offered its own LP-mode, which also doubled its recording-time. All three formats sacrificed picture quality to extend record-time. (VHS and Betamax went one step further with a triple-duration recording-mode.)
All three formats were introduced with monoaural (single-track) audio. Several years after launch, high-end VHS and Betamax VCRs offered Hi-Fi stereo-audio. Video8 followed suit, adding stereo-capability to high-end camcorders. Although Beta and VHS Hi-Fi was close to CD-quality, Video8 stereo ranked somewhere between audiocassette quality and VHS/Beta Hi-Fi. All 3 systems were based upon audio frequency-modulation (AFM.) Since Video8 audio had always used AFM, stereo-playback on mono Video8 equipment was seamlessly backward-compatible (both left and right channels are properly summed together.)
To counter the introduction of the Super-VHS format, Sony introduced Video Hi8 (short for high-band Video8.) Like SVHS, Hi8 used improved recorder electronics and media-formulation to increase picture detail. In both systems, a higher-grade videotape and recording-heads allowed the placement of the luminance-carrier at a higher frequency, thereby increasing luminance bandwidth. Both Hi8 and SVHS were officially rated at a (luminance) resolution of "400 horizontal TV/lines," a vast improvement from their respective base-formats (of 240 TV/lines.) Chroma resolution (for both SVHS and Hi8) remained unchanged, well below 100 TV/lines. All Hi8 equipment supported recording and playback of both Hi8 and legacy Video8 recordings. Video8 equipment cannot play Hi8 recordings.
In the late 1980s, digital (PCM) audio was introduced into some higher grade models of Hi8 (and SVHS) equipment. Hi8 PCM-audio used 12-bit samples with a sampling-rate of roughly 32 kHz, which was far short of CD-quality. PCM-capable Hi8 and SVHS recorders could simultaneously record PCM-stereo in addition to the legacy (analog AFM) stereo audiotracks. It's important to note for those using Hi8 today, that Digital8 camcorders are not capable of accessing Hi8 PCM-audio, only the analog (AFM) audio. PCM-audio, if present, must be converted separately, at additional inconvenience to the user.
The final upgrade to the Video8 format came in 1998, when Sony introduced XR-capability (extended resolution.) Video8-XR and Hi8-XR offered a modest 10% improvement in luminance detail. XR-recordings were fully playable on older non-XR equipment, though without the benefits of XR.
Digital8
Introduced in the late 1990s, Digital8 is a digital-video (miniDV) codec using Hi8 media. In engineering terms, Digital8 and miniDV are indistinguishable at the logical-format level. Digital8 uses the same cassette-media as Video8, but otherwise bears no resemblance to the Video8 analog-video system. Some Digital8 equipment can play (not record) Hi8/Video8 recordings, but this is not a standard feature of Digital8 technology. To store the digital-encoded audio/video on a standard Video8 cassette, the tape must be pulled faster through the recorder. This means that where the same tape will record 120 minutes of analog Hi8 NTSC video or 90 minutes of analog Hi8 PAL video, it will only record 60 minutes of Digital8 PAL/NTSC video. More recent Digital8 units offer an 'LP' mode, which increases recording time to 90 minutes.
Digital8 uses Sony has licensed Digital8 technology to at least 1 other firm (Hitachi) who marketed a few models for a while, but presently, only Sony sells Digital8 consumer equipment.
Compared to Digital8, the consumer miniDV format uses smaller tape-media and a correspondingly smaller cassette shell. Since both technologies share the same logical audio/video format, Digital8 can theoretically equal miniDV in A/V performance. But as of 2005, Digital8 has been relegated to the entry-level camcorder market, where price and not performance is the driving factor. Meanwhile, miniDV is the de facto standard of the digital camcorder market. miniDV equipment spans all aspects of the consumer market, from the price-conscious to the technically-inclined. (Edit note by a new contributor, Digital-8 appears to have less drop outs. However, today I encountered a clients Digtial-8 tape, although the picture is quite acceptable, the sound was dropping in and out. The first time I have witnessed this. It's disappointing that neither mini-dv or digital-8 have a linear cue track, "just in case". I don't think we will be able to salvage the audio. S-VHS had both HI-FI audio AND a redundant mono or stereo linear track. Inevitably, one or the other audio track would have recorded even if there was a picture related problem.)
Numerous manufacturers have now released camcorders that incorporate writable DVD-R as their storage medium. The DVD-R camcorder has the advantage of direct-compatibility with a large installed-base of DVD-players. As DVD-players continue to saturate consumer households, DVD-R camcorders will likely increase in popularity. (edit note by a different contributor, DVD-R camera recording may be a sham because it is not a true editing format. DVD-R is a heavily compressed format and is NOT a wise choice for anyone who may want to edit their footage at a later time.)
Transferring 8mm footage to a computer for editing
Because Video8 and Hi8 are analog video formats, transferring either to computer requires digitization.
Some Digital8 cameras offer legacy playback of Video8 and Hi8. Those which also have a FireWire socket will produce a digitized signal for capture to computer. This approach will provide noticeably sharper results than the method described in the next paragraph. It will also have the benefit if allowing you to work in the industry standard DV format on your computer.
If you don't have access to a Digital8 deck with which to digitize your Video8 or Hi8 tapes, you'll need an analog capture card or converter. Once on the computer, the footage can be edited, processed and transferred to DVD, the Internet or back to tape.
Some consumer miniDV and DVD cameras feature a built in analogue to digital converter that will convert an analog video source into digital form. This is usually called 'pass through' because as the footage passes through the camcorder, it is digitized and output through its firewire connection which is then (for example) connected to your computer.
Lifespan of 8mm Tapes
It is also worth noting that 8mm tapes (like all videotape) will eventually deteriorate and lose their recorded contents over time, resulting in image noise and drop-outs building up as time goes by. Tapes older than 10 years may start to show signs of degradation. Amongst other problems, they can become sticky and jam playback units or become brittle and snap.
Of course, the 8 mm format is no more prone to this than any other format. In fact, the metal particle technology used with the Video8 formats is more durable than the metal evaporated type used with MiniDV. Hi8 tapes can be either of Metal Particle (MP) or Metal Evaporated (ME) formulation.
Damaged videotapes can be repaired by specialist companies and usually restored to their former glory. Professional transfer centers also correct dropouts resulting in a cleaner restoration.
Like all videotape, 8mm tapes should be stored vertically out of direct sunlight, in a dry, cool dust free environment. Because 8mm tapes use a metal formulation, they are harder to erase than the oxide tapes used with VHS, SVHS and Betamax tapes. As such, carefully stored, they are less susceptible to magnetic fields than the older formats.de:Video 8 fr:Hi-8 ja:8ミリビデオ