Video tape is a kind of magnetic tape, which is mainly used to record and play video.Generally, video recorders are used for recording and playing. It is a linear video storage mode. Recently, due to the development of digital storage technologies such as VCD and updated DVD, video tapes are no longer the mainstream video recording media, but are still widely used in specific fields, such as digital DVRs.
Generally speaking, videotapes are used according to thevideo recorderIt can be divided into VHS, Beta, V2000 and 8mm video tapes.VCRs commonly used in families are all VHS type.VHS video tape can be divided into standard video tape, advanced video tape and high fidelity video tape according to its performance.The standard video tape is marked with ST (standard type), HS (high standard type), SP (ultra-high standard type) and FR (high quality resolution type). It is suitable for ordinary video recorders.High fidelity video tape is marked withHi-FiTag, which is suitable forhigh fidelityThe video recorder with audio function can be used to record TV programs with saving value.
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The number marked on the videotape represents the length of time (minutes) that the videotape can use, but this is only relative to a certain system.
Video tape
aboutPALSystem and N-system, taperunning speed It is different.For VHS videotapes, the running speed of N system is nearly twice faster than that of PAL system. N system models start with T, and PAL system models start with E.
8mm type video tape, N-type video tape is 1/4 slower than PAL type video tape, N-type video tape starts with P6 and PAL type video tape starts with P5.This is why the 8mm video tape is superscript for 120 minutes, but actually it only takes 90 minutes.
The performance of N-system and PAL system videotapes is the same, only the time is different.
MiNiDV tape can be divided into two types: tapestorageAnd without memory.
Those with memory are marked with "IC", and the video tape is marked with IC memory. Some cameras can read, write and search the shooting date or title and other data.
With CIII4KThe video tape storage capacity of the logo is 4KB, and the maximum capacity of data that can be recorded is as follows:
Video tape
INDEX 32 TITLE 25
DATE 6
PHOTO 12
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VHS format（VideoHomeSystem）
This format isJVCIt was launched by the company in 1976 and is used in Chinese familiesvideo recorderMost of them are in this format.
This isSonyIt is developed by the company to fight against VHS.
VHS-C format（VideoHomeSystem-Compact）
The cartridge is almost half the size of a VHS type cartridge.8mm/Hi8, etc.
U-type machine: 3/4-inch professional video recorder (with high/low tape).drumThere are two（Y/C）Video recording and playingheadThe two heads record one field signal every rotation cycle, and the rotation frequency of the head drum is 25Hz.The magnetic drum diameter is relatively large, and the recording speed is highMagnetic traceIt is wide, and there is a blank protection area between adjacent tracks.There are two audio tracks, one control track, and the control pulse (CTL) signal is recorded.
Betacam SP video recorder: use 1/2 inchMetal tape。It uses components to record two pairs of magnetic heads simultaneously and independently to record brightness andchromaSignal.Chromaticity signal is adoptedtime axisCompression (CTDM) technology, which overcomesdefinitionReduction, color distortion, and signal to clutter ratio reduction.
MII format component video recorder: high-quality 1/2 inch component video recorder launched by Panasonic, also using metal tape, analog componentRecord mode，image qualityGreatly improved, mainly used for electronicsNews interview, also applied toLive programsProduction, due to mechanical parameters, magnetic traceConfigurationThe signal processing is different from that of Betacam SP.
Brightness signal of DV systemSampling frequencyUp to 13.5MHz, the sampling frequency of color signal can also reach 3.375MHz, and the definition can theoretically reach 500 lines,Video SNRUp to 54dB.The sound system is also very sophisticated, with 16 bits/48 bitsKilohertz44.1 kHz 32 kHz two channel and 12 bit/32 kHz four channel specifications.
DVCPROIn 1996, PanasonicDV formatA new digital format based on.It adopts 4:1:1 sampling, 5:1 compression and 18 μ m magnetic trace width.In 1998, DVCPRO50 was launched on the basis of DVCPRO. It uses 4:2:2 sampling and 3.3:1 compression.In 1999, a more advanced product DVCPRO100, also known as DVCPRO, was launchedHD, to a higher level of digital TV--HDTVField development.DVCPRO family can meet the requirements of on-sitestudioAnd moreBroadcast levelAnd professional applications.
Digital VHS format
It is a new professional digital component video recorder (also known as D-9 format) launched by Japan JVC in April 1995.It is a video recording standard developed on the basis of S-VHS technology and has an efficient encoding digital technology S-format. It can replay S-VHS image signals. The video tape width is 12.7 mm (1/2 inch). It uses 4:2:2 sampling, 8BIT quantization, intra frame 3.3:1 compression, and video data rate is 50 MBPS.It can record 4 channels of audio, 48KHZ sampling and 16BIT quantization for each channel.
In 1996, digital equipment in DVCAM format was introduced. The 5:1Compression ratio, 4:2:0 (PAL) sampling mode and 8-bit digital component recording ensure the high quality of the picture, and can be compatible with the playback of household digital DV video tapes, with excellent cost performance.
Betacam SX format
It usesMPEG-2MP@ML's extension 4:2:2P@MLStandards.High compression ratio (10:1) while ensuring high image quality
Digital Betacam format
SONYThe company launched Betacam digital component video recorder in 1993.Use 1/2 inchMetal band。video signal4:2:2 sampling is adopted,Digital input10BIT quantification,Analog input8BIT quantization, intra 2:1data compressionDigital recordEditing has become the current television fieldtechnological development The mainstream of.In the process of TV program production, the link that can best reflect the benefits of digitalization to images is the video recorder, which basically does not affect the image quality after multiple generations of replication. Its core is digital recording technology.Therefore, all major manufacturers are sparing no effort toResearch and developmenthighestPrice performance ratioDigital recording equipment.The emergence of digital technology has thoroughly solved the problem of image quality degradation that has puzzled TV workers for many years due to post production.
Digital video recorderThe development ofRecord formatThere are two categories: uncompressed and compressed.Video recorders in uncompressed recording format includeD1、D2、D3、D5It is based on the original signalCode rateDirect recordInput signalThe original level of the signal is maintained, which is a nondestructive record.The recording mode is divided into digital components (D1, D5) and digital composite (D2, D3),They represent the highest standard of video recorder equipment, with the highest image quality and the smallest signal loss. However, due to the large amount of image signal data and the extremely strict requirements for machine hardware, the price is very expensive. Although the products have been available for several years, only a few advertising companies and other units with extremely high requirements for image quality have used them in a small amount, which has not been promoted in domestic television stations.
Since the 1990s, due to digital video rate compressionradio and televisionAll fields are rapidly popularized, M-jPEGMPEG-2Compression standardIt is widely accepted by all walks of life.In recent years, a number of digital video recorders using rate compression have emerged, that is, on the premise of ensuring that the image quality does not decrease significantlycompression technique To reduce the bit rate, thereby reducingsignal processing The difficulty and cost of recording.At the same time, on this basis, the post editing processing is implemented indigital environmentIn.It has greatly improved the quality and function of program production, and its comprehensive performance price ratio is significantly better than analog equipment, providing a technical and economic possibility for TV station equipment to transition from analog to digital.
Low price digital video recorders, such as digital Betacam (DVW) and DVCPRO, have become the mainstream products of digital recording equipment.It is also the most popular variety on the marketcompatibilityDifferent video formats have different applications.
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Recording format of different recording formats
DIGITAL-VHS:
DIGITAL-S video recorder format is a new professional digital video recorder launched by JaPaNJVC in April 1995.It is developed on the basis of S-VHS technology with efficient codingdigital technique S format video recorder, which reproduces S-VHS image signals. The width of the video tape is 1/2 inch, completely according to COIR601Standard design, 4:2:2 sampling is adopted, and internal frame coding is performed at 50Mb/s digital sampling speed（M-JPEG）The compression ratio is 3.3:1, and its main parameters are shown in the table below.
Use magnetic tape metal coating tape, with a bandwidth of 12.65mm
The cartridge used is the same as the W-VHS cartridge (188mm × 104mm × 25mm)
Record time 104min (124min under development)
The belt running mechanism is based on the mature and reliable S-VHS belt running mechanism. The size of the magnetic drum is 62mm and divided into three layers. The upper and lower drums are fixed. The middle drum is rotated with a rotating head.This form can reduce the tension of the tape. The recording and playback heads of the editing video recorder are separated andReplay head90 degrees ahead, so it has an advanced image pre reading function: that is, before the VCR records a new signal, it can play thedigital signal。With this function, you can complete the functions of the two to one editing system, such as scribing and overlapping, without the need for a third machine.
1. Tape and cassette
The tape used for digital S is W-VHS tape that can record and replay high-definition television broadcasting. It is metal coated tape,Magnetic resistivity1800 Aust, with the highest performance of the same type of tape.High signal to clutter ratio can be obtained at high frequency, and the dust-proof structure of the tape box is strengthened in the aspect of tape walking performance. The recording time of W-VHS tape is 104 minutes.
2. Tape recording format
Four recording and playback heads are used respectivelyVideo headAt 15 degreesazimuthIt is configured in pairs, and two magnetic tracks are recorded at the same time.1-frameVideo data12 magnetic traces are recorded in 625/50 system.
sound signalFour kinds of sound data can be recorded in one frame of image. These sound data are recorded separately in a group of two magnetic tracks.The sound channel of digital S can have four channels in the format, but there are only two channels in the market.
Digital S is equipped with four playback heads. Even if one or two heads are blocked, since the image is replaced every two frames, the image of the previous frame can be used for masking.
3. Video and Audio Processing of Digital S
First, simulate YCRCB shall be digitized in 4:2:2 format, and the brightness sampling frequency of 13.5MHz is the same as that of horizontalSynchronizing signalSynchronization.According to the 4:2:2 standard, the number of effective lines per frame in the 625/50 format is 576, that is, from 23 to 310335 to 622.DIGITAL-S adds 2 rows of reverse travel, mainly to save the original data of reverse travel. See the table below for the sampling specifications of image signals.
Fg 525/60 system 620/50 system
Sampling frequency Y
CR/CB 13.5MHz is synchronized with horizontal synchronization signal
6.75MHz
Total samples/row Y
CR/CB 858 pixels 429 pixels 864 pixels 432 pixels
Effective samples/row Y
CR/CB 720 pixels 360 pixels
Effective lines/frame 480 lines 576 lines
V-AUX uncompressed rows 2 rows 2 rows
Number of valid lines: odd field
Even field 23...... 262
285……524
23……262
285……524
Quantization form Y, CR/CB are all 8bit linear quantization
Digital channel connector（DCI）It can include all kinds of digital video recordersIdentification dataAnd for efficient recording and playback on tapedigital dataNecessary channel coding and modulation processing.
Digital S ensures thatInterchangeabilityThree ITI signals on the digital magnetic track are used for tracking servo.The width of the magnetic trace recorded at ± 15 ° azimuth is 20 μ m, and the width of the playback head is 1.4 times of the magnetic trace. However, due to the use of azimuth recording, it is not easy to be affected by the noise of adjacent magnetic traces, so that a good playback image can be obtained.
When inserting and editing, the noise of the last same azimuth signal remains, which has more serious impact than the adjacent magnetic trace noise.In order to solve this problem, digital S uses a rotating erasing head to erase the signal with the width of more than two magnetic traces, and then uses the same magnetic trace widthRecording headRecord.It can form certainProtective tapeTo prevent deterioration of the image quality at the edit switch point.
4. Structure of magnetic trace
The digital signal after the number is repeatedBlockingAnd sorting.In the method of blocking and sorting, CR and CB form DCT image blocks according to 8 × 8 pixels in space (DCT pixels areImage transformationInto many blocks of 8 × 8 pixels), and then a total of four image blocks (two Y image blocks, one CR image block and one CB image block) consisting of brightness signal and chrominance signal at the same position on the image screenMacroblock。The macroblock and synchronization block are both error codesWhen correctingThe error concealing unit of.Close 54 macroblocks form a superblock, and adjacent tracks are recorded at different azimuth angles to increase the reading timeuseful signal The signal-to-noise ratio of.Therefore, the superblock is divided into two groups, 27 macroblocks each, which are recorded with positive and negative azimuth angles respectively.Each frame has 720 × 576 × 2=829440 pixels (625/50), and 829440 ÷ 64 ÷ 4 ÷ 54=60 superblocks.Similarly, for 525/60, there are 50 superblocks per frame.60 super blocks are divided into 12 lines, 5 super blocks in each line, and recorded on 12 magnetic tracks, 12 magnetic tracks are divided into 6 pairs, and then recorded on the tape in sequence, and the partitions on each magnetic track.
Each magnetic trace starts from the lower end of the tape and is divided intoInterpolationIt is G0 to G8 with ITIO: Insert and Track Info formula - O, video segment i (Video-i), interpolation and track information segment I (ITI-1), sub code segment (SVBCOE), audio segment i (Audio-i), audio segment j (Audio-j), and video segment j, respectively.Each area has a pre segment code and a post segment code.In addition, there are two prompt tracks and control tracks in the direction of tape movement, which can be used to obtain good editing operability.
8 regions of j (Video-j) and interpolation and track information segment 2 (ITI-2).There are coding gaps between the start and end areas, G0 to G8, respectively.Each area has a pre segment code and a post segment code.In addition, there are two prompt tracks and control tracks in the direction of tape movement, which can be used to obtain good editing operability.
Betacam-SX：
B etacam SX is SONY's disc tape integrated digital video recorder, which uses MPEG-2MP@ML's extension 4:2:2P@MLStandards.Therefore, the video recorder has a high compression ratio (10:1) while ensuring high image quality, and can be used on site with hard disk modelsNonlinear editing, the recorder equipped with SDDI (Serial DIGITAL Data Interfare) interface is availableCoaxial cableTransmit recorded data at quadruple playback speed.
4：2：2P@MLThe connotation of the compression scheme is toMPEG-2Main category and main level in the standardMP@ML(Main profile at main level~main class main level)Reference StandardsAt the same time, considering the needs of transmitting materials and production, the 4:2:0 sampling in the main class and main level is changed to 4:2:2 standard sampling, which relatively improves the quality of transmitting materials.Then MPEG-2 compression is applied, taking into account the editing requirements, and I-B frameConstitutiveGOP(GROUP OF PICTVRES) image group sequencedata streamThe editing system of is synchronized with the GOP boundary of two frames and four fields, and the switching point is always selected in theIframeOn, implementhigh-precisionEditing ensures the production quality of the entry screen.
1. Tape recording format
Betacam SX track format.Use a 1/2-inch metal coated tape.The organization of magnetic trace is different from that of other video recorders. It is not organized by frame, but by GOP (equivalent to two frames, namely I frame and B frame).For 525/60 system, each GOP plusError correcting codeAfter that, 10 oblique magnetic traces were formed;For the 625/50 system, 12 oblique magnetic traces are used. In the arrangement of magnetic traces, the video magnetic traces are placed on both sides and 8 segments are arranged in the middleAudio dataAnd two segments of system data.In addition, there are three longitudinal magnetic traces, one auxiliary magnetic trace, one time code magnetic trace and one control magnetic trace.
The magnetic trace width of Sx is 32mm, which is wider than the other two models. Generally, the wider the signal magnetic trace is, the higher the s/n ratio is, and the smaller the code rate of digital signal is.
2. Digital video processing
When editing the hard disk, first copy any video and audio data of the tape to the hard disk, and then edit in any order according to the file index.This process does not really change the order of disk contents, but changes the edit decision table (EDL).SDDI codec interface enables the data recorded on the tape to be copied to the hard disk at four times the playback speed.Betacam SX has a strong error correction capability. Even if two tracks are lost in one GOP, error correction can still be carried out normally.
Another feature of Betacam SX is that the playback head has doubled.Generally, a certain magnetic head can normally read data, which reduces the requirement for the accuracy of magnetic trace.Using this technology can make the playback within ± 1 times the speed reach zeroClutterImage of.
DVCPRO：
DVC(DIGITAL VIDEO Cassette) YesPanasonicHome DV digital component recorders jointly developed by more than 50 companies in the world.DVCPRO is a format that fully exploits and expands the format of DV digital video recorder for home use. Its biggest characteristics are small cassette tape and long playback time.Due to the use of 1/4-inch tapes, the tape transport mechanism has been reduced accordingly.Its compression scheme is sensitive to all possible parameters, such as compression damage, motion code rate, image subjective quality, durability, multi generationReplicationAfter comprehensive consideration, a comprehensive system from ordinary digital TV to high-definition TV, including various levels, has been produced.For ordinaryTV signalThe 4:2:2, 4:1:1, or 4:2:0 digital components are used. Because all samples of the brightness components are kept, the resolution is very high (the same as D1 and D5). The compression ratio used at 4:2:2 is 3.3:1, and the bit rate is 50Mbps;4: The compression ratio of 1: and 4:2:0 is 5:1, and the bit rate is 25Mb/s.absolutelyDigital rateThe reduction of DVCPRO enables the compression system to work within the frame, so the frame accuracy can be controlled and edited.Although the compression scheme is inconsistentMechanical structure, cassette, record format anddata structureIt is precisely described and defined.And enable most circuits to be packaged into two integrated circuits (i.eChipsetSame), so that they are compatible.
1. Tape recording format
The magnetic tape adopts highly reliable metal particle tape (MP) with a total thickness of 9 μ m.Because the metal particle tape is suitable for longitudinal recording (different from the metal coating tape), it can provide simulationAudio promptMagnetic trace (atUpper edge）And control magnetic trace (atBottom edge）。The use of the control track allows fastservo systemWhen the machine is stopped and replayedConversion processThis is the key to shorten the pre roll editing time and frame precision editing.The prompt magnetic trace not only provides the user with the third audio channel, but alsoDigital audioIf it is not available, provide another method to obtain audio.
The magnetic trace format of DVCPRO adopts 21.7mm direct magnetic drum and the usual 1/2 inchVCRCompared with DVCPRO, the magnetic drum diameter of DVCPRO video recorder is 3.5 times smaller, which not only reduces the total mechanical volume and weight of the video recorder, but also reduces thepower loss And the rotating noise of the magnetic drum.The rotating speed of the magnetic drum of the video recorder is 150 rpm/s,Helical scanningThe width of the recorded magnetic trace is 18 μ m, and the magnetic trace index (the ratio of the width to the length of the recorded magnetic trace) is three times larger than that of the D3 format, and is similar to that of the simulation format.Six magnetic heads are installed on the magnetic drum, namely two recording heads, two instant replay heads and two rotating demagnetization heads.Rotating demagnetizing head is used to assist insertionEditing function, the real-time playback head can be used to record and playback images at the same time for real-time inspection of recording quality, and can also work with the recording head to complete the forward and reverseSlow motionReplay.The sound channel samples at 48kHz, quantizes at 16bit, and simultaneously records the uncompressed digital audio signals of the two channels.
The ITI (Insert and Tracking Information) code at the beginning of the magnetic trace is mainly used to provide insertion and tracking information when inserting the code. New data will be recorded after the ITI code. Except for re recording, the ITI code will not be rewritten.In subsequent audioData segmentAnd video data segments with editing gaps on the left and right, 3 segments in total:G1、G2、G3。Sub code after G3 records verticalTime codeOr reverse travel time code data.There is still some margin left behind.Each frame has 12 magnetic traces (625/50 system) and ± 20 ° azimuth recording.The tape speed is 33.813mm/s, the audio is a two channel PCM, and one channel longitudinal prompt magnetic trace, with a sampling frequency of 48kHz.In addition, there are two independent LTC/UITC time codes.Both time codes can be read at any tape speed.
The dip angle θ of the magnetic trace is 9.1784 degrees, the width of the control magnetic trace is 0.4mm, the prompt magnetic trace width is 0.35mm, the total length of the spiral scanning magnetic trace is 32.842mm, and the video recording length is 27.548mm.
2. Video processing
DVCPRO includes DVCPRO50 and DVCPRO25. It can switch between the sampling formats of 4:2:2, 4:1:1, and 4:2:0. The compression ratio is also different and can be switched.Their signal structures are compatible, and can also be in 525 lines and 625 linesTV systemIt can record and replay materials in 25Mb/s and 50Mb/s formats.DVCPRO achieves 4:2:2 recording by using two sets of DVCPRO chipsets in parallel.The compression ratio of DVCPRO50 is reduced to 3.3:1, while that of DVCPRO25 is 5:1.Take 4:1:1 as an example to illustrate theProcessing。The sampling frequency of video brightness signal is 13.5MHz,Chromatic aberration signal3.375MHz and 3.375MHz, the brightness resolution is the same as D1 and D5, and the chromaticity bandwidth is 1.5MHz, the same as Betacam SP.Video data compression mainly adopts DCT and variable word length coding.
First, the 4:2:2 digital signal changes from 216Mbps to 162Mbps after 4:1:1 conversion.Transformed input toimage compression The encoding unit is compressed from 162Mbps to 24.948Mbps, and then toError correcting codingConcurrent menstruationScrambling codeOutput to record symbolizationprocessing unit, recorded on magnetic tape by rotating the head.
The specific process of rate compression.There are 526 effective lines in 625 lines of each frame, odd field from 23 lines to 310 lines, even field from 335 lines to 622 lines, 288 lines per field.The quantization level of brightness signal ranges from 1 to 254, the white level is 235/the black level is 16, and the color difference isZero level(Gray level) 128 A total of 255 quantization levels are the same as S, the brightness and color difference sample values are divided into image blocks according to 8 × 8, and the image blocks are positioned according to (X, Y), the horizontal is X, and the vertical is Y.Y. CR and CB respectively form image blocks according to frames. For this reason, there are 72 × 90=6480 DCT image blocks with brightness, and CR and CB each have (18 × 2) × 45=1620 image blocks. Then four brightness image blocks and one image block of CR and CB form a macro block.For 625/50, 1620 macroblocks are formed, then 27 macroblocks form a superblock, and 60 superblocks can be obtained.The 60 superblocks are divided into 12 lines, and 5 superblocks in each line are recorded on 12 magnetic tracks, which is the same as S, that is, 12 magnetic tracks are recorded per frame.
In a word, DVCPRO50 is not only compatible with DVCPRO25 in playback and recording, but also fully compatible at the data stream levelSeamless switching。This allows DVCPRO to switch and create series programs in servers that store 25Mb/s and 50Mb/s files.
The "format war" has a long history. For users, there are both joys and sorrows: the joy is that due to the numerous format competition, the performance and price of various machines have a choice;The worry is that improper selection will bring a lot of inconvenience to the work, even lead to backlog and waste.Therefore, when purchasing digital video recorders, you should choose them according to the specific circumstances and use occasions, and pay attention to the use and configuration of resourcesrationalitySystematization of equipmentOpenness, compatibility and operation cost, etc., and should give due consideration to foresight, try to make the best of everything, and get the maximum benefit with the least investment.
From the perspective of image quality,Digital Betacam format4:2:2 sampling, 10bit quantization, and intra frame 2:1 compression are the highest level in today's compressed digital devices.Betacam SX is inter frame 10:1 compression, and the bit rate of 18Mbps is the lowest among several modern video recorders, so it reduces the operating cost. Its image quality is slightly inferior to digital Betacam but can reach the B level.The DVCAM format developed by SONY on the home DV format is 4:2:2 sampling, 8bit quantization, intra frame 5:1 compression, and the image quality is close toPVWHorizontal.Panasonic's DVCPRO50 is an upgraded product of DVCPRO. With 3.3:1 compression in the frame and 50Mbps bit rate, the image quality is close to DVW, while the DVCPRO25 bit rate is 25Mbps, and the image quality can reach the PVW level.JVC's DIGITAL-S, 3.3:1 compression within the frame, and 50Mbps bit rate image quality close to DVW level.
In short, these digital video recorders are still inDevelopment stageSome technical problems need further improvement.It is believed that in the near future, the digital video recorder equipment will become more and more perfect, the price will become cheaper and the image quality will become higher and higher.
Magnetic trace inclination (degree) 5.57 4.621 9.1784
Replay compatibility with S-VHS playback function to replay existing Betacam
Oxidation zoneCompatible with material DVCPRO-25.50 on metal belt
Image quality is close to DVW level, equivalent to BVW level PVW (close to DVW)
Service life of magnetic drum ≥ 800h is 3 times of PVW, about 2400h>1
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Many schools also keep many videotapes.However, the preservation and use of such materials are far inferiorVCDConvenient.OneCD writerThe price has been quite cheap, and the disc is even cheaper to a few yuan a piece.It is a good choice to turn video tapes into VCD discs for saving.
Now, let's introduce some methods and techniques for the engraving of VCDs.
Input signal
The first step of converting video tape to VCD is toanalog signalConvert to digital signal.If you want to save byDigital video cameraHigh definition DV signal taken needs a higher gradeVideo capture card。But if you record ordinary video signals, you only need a cheap oneTV cardOr universal video capture card is enough.Now we will begin recording in three steps.
The first step is to use videoAudio cableConnect the video out end of the video player with the video in of the TV card, and connect the audio out of the video player with the line in of the sound card.
The second step is to record the audio and video signals sent by the video player into a video format of 352 × 288, 25 frames per second, using the program provided with the TV card,Sound format44.1kHzstereoOfAVIFile.
The third step is to use heroes to solve hegemony "practical"Content-"AVI to MPEG" function in Common Tools or XingMPEG (TM)Encoder2.2. LSX-Mpeg Encoder3.0 and other software convert AVI files into MPEG1 (VCD) format files.But in this wayAnalog-to-digital conversion, largerdisk spaceIt also requires a high machine and speed, otherwise the video compression process will be too slow for you to bear.The universal video capture card with a price of about 1000 yuan provides MPEG1 hardwareReal time compressionFunction, without long conversion from AVI to MPEG1, audio and image synchronization can be recorded on an ordinary computerColor restorationBetterMPG files。The parameters set during recording areSIF352×288 PAL。
Video editing
If only the recorded digital movieSimple cuttingWith merger, the author suggests that it is easier and faster to use heroes to solve hegemony.Open the movie to be cut with Hero Video Jieba, set the starting point and end point of the clip, click "Record" to quickly complete the clip clip, and then name it and save it.If you want to merge two or more clips, you can use MPEG in "Utilities - Common Tools"File Merge”Function.In the pop-up "Merge MPEG toVCD format”Set the output file path in the window, open the files to be merged one by one, and finally press the "Save As..." disk mark. Several files will be merged into one MPG file in a short time.However, MPG files combined in this way can not be recorded by VCD software sometimes.At this time, just open the MPG file again with Hero Jieba, set the cutting point at the beginning of the file, set the cutting end at the end of the file, and record it again to pass.
Before recording, if you want toMPGDocument with subtitles orTransition effect, ortranscriptionIf the video is edited and synthesized, the author recommends usingUleadMediaStudio6.0 orAdobePerimier6.0。The functions and operation interfaces of the two software models are very similar, while the former has its own MPG compression program, which can directly output MPG files,Software stabilityIt also seems higher than the latter.
Burn a VCD
For beginners, the author recommendsNero Burning RomBurning software。This software supports many recorders with friendly interface and high stability.In order to ensure the success rate of burning, it is better to restart your computer, close programs running in the background such as antivirus and screen protection, and do not start other programs during the burning process to avoid burningUnderload。Then start Nero Burning Rom, click "Compile a new CD,Next，Other CD formats，Next，Video CD，Next，Finish”, enter the recording file selection window.The window is divided into two parts: the left part and the right part. The MPG files found in the right part of the window are directly dragged one by one to the blank Track (VCD track) box at the bottom left of the window, and the recording software is used to verify the VCD2.0 format.If the format does not match, a warning will pop up, otherwise the relevant information of the MPG file will be displayed on the VCD track.The total time of the engraved VCD clip can be viewed from the bottom of the windowstatus barObserved.
Generally, each blank film shall not exceed 74 minutes.After all MPEG files are dragged into the track and the sequence of clips is adjusted, presstoolbarClick the "Opens the Write CD dialog" button on the, and select the recorder's write speed in the pop-up dialog box.If recording at this speed for the first timeRadio Middle click "Test and burn", otherwise click "Burn" to save burning test time, and then press "Burn".In this case, the recorder has not been insertedCD-RBlank disc, the tray will pop up automatically and prompt "Please insert an empty medium to write to...". After inserting a CD-R blank disc, press "OK" to start recording.After waiting for dozens of minutes, until the program pops up the "Burn process completed successfully" report, press "OK", and then press "Discad".The recorder automatically ejects the disc, and a VCD is carved.This disc can get any VCD that supports 2.0 formatplayerPlay on.
