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  1. If i right the Laserdisc format support also anamorphic 16:9 widescreen?
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  2. Capturing Memories dellsam34's Avatar
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    Originally Posted by dvd3500 View Post
    Hi8 could record in in anamorphic 16:9 widescreen. It looked OK on widescreen (under 42") .
    I know it is not VHS but it is an analog format that seemed to support it.
    Consumer camcorders achieve that by manipulating CCD pixels, It is sort of letterboxing but happens in the CCD level, In widescreen mode only the center area of the CCD pixel array is used, So the vertical resolution is lost just like using letterboxing, It only gets done right if the camcorder has an anamorphic lens which it doesn't.
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  3. Originally Posted by dvd3500 View Post
    Hi8 could record in in anamorphic 16:9 widescreen. It looked OK on widescreen (under 42") .
    I know it is not VHS but it is an analog format that seemed to support it.
    Any VCR capable to record 525 and/or 625 lines 4:3video standard (NTSC/PAL/SECAM) can record anamorphic 16:9 video too...
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  4. If i right the Laserdisc format support also anamorphic 16:9 widescreen?
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  5. Originally Posted by dellsam34 View Post
    Originally Posted by dvd3500 View Post
    Hi8 could record in in anamorphic 16:9 widescreen. It looked OK on widescreen (under 42") .
    I know it is not VHS but it is an analog format that seemed to support it.
    Consumer camcorders achieve that by manipulating CCD pixels, It is sort of letterboxing but happens in the CCD level, In widescreen mode only the center area of the CCD pixel array is used, So the vertical resolution is lost just like using letterboxing, It only gets done right if the camcorder has an anamorphic lens which it doesn't.
    That explains why on my Hi8 camcorder if you enable "wide screen" recording other features get turned off, like picture stability.... Thanks!
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  6. Originally Posted by anonymoustly View Post
    If i right the Laserdisc format support also anamorphic 16:9 widescreen?
    yes, all SD formats are 16:9 anamorphic capable - true 16:9 formats are some strange pre-digital formats (like hybrid analog-digital of the Multiplexed Analogue Components family ) and modern digital format - true 16:9 is 1280x720 and 1920x1080 (and of course some newer UHD+ formats) - there is also anamorphic 16:9 in some digital HD formats (for example Sony HDV use 1440x1080 to store anamorphic 16:9 video). Of course any modern digital TV format is capable to store anamorphic formats and sometimes this is used to save bandwidth (bitrate)
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  7. Capturing Memories dellsam34's Avatar
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    Originally Posted by dvd3500 View Post
    That explains why on my Hi8 camcorder if you enable "wide screen" recording other features get turned off, like picture stability.... Thanks!
    In the later years of analog and SD camcorders when the CCD/CMOS chips reached the one megapixel mark to improve still pictures, Manufacturers used the extra resolution to get better widescreen video, so even when turning off the the top and bottom sections of the imaging sensor there is still enough pixels left (more than 480 for NTSC or 576 for PAL) but you loose digital picture stabilization because all the horizontal pixels are fully used. In 4:3 mode the center area is used for video and the surrounding pixels used for digital image stabilization, Only in photo mode the entire imaging sensor is used.
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  8. Yes, you can record anamorphic widescreen on VHS cassette. This is how I released some horrors as commercial tapes last year.
    You just need to prepare a 4:3 master that is contains anamorphic video, therefore you can enjoy 16:9 playback, instead of letterboxed widescreen, or pan&scan.
    Some analogue camcorders could record anamorphic, there were even special lenses you could mount on some camcorders to record anamorphic, though they are quite expensive nowadays, I've been hunting one for some time.

    Some DV/D8 could record anamorphic wither by cropping top and bottom from the sensor, but better models used larger sensors and would record from larger sensor area, thus offering better quality.

    And there were commercially released anamorphic LaserDiscs released as well.
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  9. First, I have always thought that "anamorphic" in regards to DVD was a misnomer: there is nothing anamorphic about it, it just has different PAR compared to "fullscreen" format, and this results in a different FAR. Neither 4:3 nor 16:9 DVD format is natural in a sense it is not borne to mechanical or optical relationship between a lens and film stock, like it happens in case of anamorphic film, where anamorphic lens squeezes the image, and the picture has characteristic ellipsoidal bokeh.

    As for analog video, it has no baked-in AR and can have whatever proportions you want it to have. Old TV sets had controls to adjust frame width and height, and you could squeeze or stretch it any way you wanted to. Analog video specifies number of lines per field/frame and number of fields/frames per second. Each line has certain duration, but it is up to the display device and the user to decide how long it should be. All that is required is that each line took specific time to swing from one side to another, that is all.

    4:3 proportions of analog TV and video was just an agreement, it was not enforced in the signal (well, until PALPlus added 4:3 and 16:9 flag). You can record widescreen video on a VHS VCR and play it back, and it will play back just fine. For the VCR these are just lines. All you need is a TV that allows to switch between 4:3 and 16:9 modes.

    TL;DR: yes, you can record widescreen on VHS with absolutely no problems. It is all about how you interpret it.
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  10. Originally Posted by Bwaak View Post
    different PAR
    You mean different SAR, as in Sample Aspect Ratio. Because in SD video there are no pixels, there are samples, which comes directly from the backwards compatibility of ITU-R BT.601 with ITU-R BT.470.

    There were VCRs that could encode a flag for anamorphic video, that some TV sets were able to recognize and adjust aspect ratio automatically, this even affects DV/D8 equipment when the signal is input from VCR into them.
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  11. Originally Posted by SF01 View Post
    Originally Posted by Bwaak View Post
    different PAR
    You mean different SAR, as in Sample Aspect Ratio. Because in SD video there are no pixels, there are samples, which comes directly from the backwards compatibility of ITU-R BT.601 with ITU-R BT.470.

    There were VCRs that could encode a flag for anamorphic video, that some TV sets were able to recognize and adjust aspect ratio automatically, this even affects DV/D8 equipment when the signal is input from VCR into them.
    In my first paragraph I was talking about DVD, for which pixels definitely exist. DV/Digital8 are digital formats, like DVD, and they do have 4:3/16:9 flag. Analog video does not have pixels, and the number of samples is limited by bandwidth and varies depending on broadcast TV format or video recording format, but the number of lines and the duration of the line are known.
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  12. Originally Posted by Bwaak View Post
    Originally Posted by SF01 View Post
    Originally Posted by Bwaak View Post
    different PAR
    You mean different SAR, as in Sample Aspect Ratio. Because in SD video there are no pixels, there are samples, which comes directly from the backwards compatibility of ITU-R BT.601 with ITU-R BT.470.

    There were VCRs that could encode a flag for anamorphic video, that some TV sets were able to recognize and adjust aspect ratio automatically, this even affects DV/D8 equipment when the signal is input from VCR into them.
    In my first paragraph I was talking about DVD, for which pixels definitely exist. DV/Digital8 are digital formats, like DVD, and they do have 4:3/16:9 flag. Analog video does not have pixels, and the number of samples is limited by bandwidth and varies depending on broadcast TV format or video recording format, but the number of lines and the duration of the line are known.
    Pixels exist on digital displays. DVDs, DV, etc do not inherently have pixels, because those are not pixels, they are samples.
    Analog video does not have samples either. The number of samples in SD video does not vary, it is specifically a consequence of the sampling rate of 13,5 MHz as specified by ITU-R BT.601, which is why they are called samples, not pixels, especiall that they are never square in commercially released SD formats, such as DVDs, DV tapes and other SD tapes for professional use.
    Yes, the number and duration of lines are known, as specified in ITU-R BT.470.

    So because the analog signal is a line of specified length, the line can be drawn over longer, or shorter surface, thus allowing for drawing 16:9, or 4:3 image. And I could assume that it could be played with further to achieve ultrawide image.
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  13. Member Skiller's Avatar
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    Originally Posted by SF01 View Post
    There were VCRs that could encode a flag for anamorphic video, that some TV sets were able to recognize and adjust aspect ratio automatically, this even affects DV/D8 equipment when the signal is input from VCR into them.
    It's called WSS and it is a series of dashes (=bits) in the first half of line 23 in a 625 lines analog signal. This also happens to be the first line in a 576 lines digital frame.

    Here is an example, I recorded this off DVB-S many years ago and read out the WSS bits in ProjectX:

    Image
    [Attachment 63575 - Click to enlarge]


    The bits say:

    WSS status @ line 0 (23):
    Run-In-Code found @ 7
    Start-Code found @ 36
    Group 1 (Picture Format) start @ 60:
    * 4:3 full format, 576 lines, full screen #Makes a TV switch to the correct aspect ratio (unless overridden or not supported)
    Group 2 (Picture Enhancements) start @ 84:
    * camera mode #aka interlaced
    * standard PAL #no PAL-plus
    * no helper
    * reserved (0)
    Group 3 (Subtitles) start @ 108:
    * no subtitles in teletext
    * no 'open subtitles'
    Group 4 (others) start @ 126:
    * no surround sound
    * no copyright/unknown
    * copying not restricted
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  14. Capturing Memories dellsam34's Avatar
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    Originally Posted by SF01 View Post
    So because the analog signal is a line of specified length, the line can be drawn over longer, or shorter surface, thus allowing for drawing 16:9, or 4:3 image. And I could assume that it could be played with further to achieve ultrawide image.
    You can do that in digital as well, It's called resizing, Albeit with a slight loss in quality due to mathematical approximations, Versus a scan line drawn on a silver coating of a B&W CRT screen where stretching is lossless (not the case though with a color TV that has a shadow mask). Also modern monitors do that when displaying an anamorphic 720x480(576) frame, Just resize 720 to 1920 (HD) or 3840 (UHD), the same goes for the vertical axis.
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  15. New technical information, I haven't come across before, thank you Skiller.

    You can do that in digital as well, It's called resizing, Albeit with a slight loss in quality due to mathematical approximations, Versus a scan line drawn on a silver coating of a B&W CRT screen where stretching is lossless (not the case though with a color TV that has a shadow mask). Also modern monitors do that when displaying an anamorphic 720x480(576) frame, Just resize 720 to 1920 (HD) or 3840 (UHD), the same goes for the vertical axis.[/QUOTE]

    Actually, the 720 samples of SD video contains blanking overscan lines that when used to stretch to 1920, or 1440 will display distorted image in incorect aspect ratio, those need to be trimmed off for export in square pixel format, or custom aspect ratio used in VLC. NTSC video has active image area in center 704 pixels, PAL in center 702 pixels, this is specifically written in ITU-R BT.601 and comes directly as the result of the length of the active image portion of the scan line as specified in ITU-R BT.470 and the sample rate of 13,5 MHz.
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  16. Capturing Memories dellsam34's Avatar
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    Most people don't crop to 704, only few see that as an important step. The reason for adding 16 blank samples based on what I've read was based on the fact that the frame in imaging sensors of old video cameras and telecine machines wasn't always centered and clean when recorded to a video tape, Some had the frame slightly to the left, some had it to the right and often a combination of both, Vertically the number of scan lines is defined, no issues there, But horizontally not so much, So the decision to over sample by 16 was made.
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  17. Originally Posted by dellsam34 View Post
    Most people don't crop to 704, only few see that as an important step. The reason for adding 16 blank samples based on what I've read was based on the fact that the frame in imaging sensors of old video cameras and telecine machines wasn't always centered and clean when recorded to a video tape, Some had the frame slightly to the left, some had it to the right and often a combination of both, Vertically the number of scan lines is defined, no issues there, But horizontally not so much, So the decision to over sample by 16 was made.
    And withut that step the image is not a true 4:3, or 16:9 if resampled to 640/853, or 1024/768 pixels.
    That is true, I can often see analgo video slightly off center.
    Horizontally there can be always drift in the various equipments, especially the converters they might start too early, or too late to convert the incoming signal, thus it might not be strictly in the enter.
    Most, if not all modern displays, players, youtube, don't know how to properly display the SD video and the fact that DV video uses all 720 sampels for video, not only the center 704/702 and later DVD manufacturers started usign full 720 for the active imae with non-compliant SAR only adds to the problem.
    Fortunately most ITU-compliant NLEs implement proper SAR, when handling SD video.
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  18. Capturing Memories dellsam34's Avatar
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    Yes at 720 the aspect ratio is about 3% off, Even with older DV camcorders, only 704x480(576) is framed as 4:3 and the 16 pixels are just extras filled with active image outside the 4:3 frame, I however found that the very late models with higher resolution imaging sensor and the HDV camcorders just format the entire 720 as 4:3. Some people disagreed with me but if I get a hold of one of those camcorders I will do a circle test.
    Last edited by dellsam34; 24th Jan 2023 at 15:56.
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  19. Originally Posted by dellsam34 View Post
    Yes at 720 the aspect ratio is about 3% off, Even with DV camcorders, in the older models only 704 is 4:3 and the 16 pixels are just extras outside the 4:3 frame, I however found that the very late models with higher resolution imaging sensor and the HDV camcorders just format the entire 720 as 4:3.
    Interesting. I would have to run some tests on HDV models.
    Would they also distort the HDV image, when downconvertingto DV output?
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  20. Capturing Memories dellsam34's Avatar
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    Please do, Shoot about one minute of a black circle like a dark label of a CD on a white background, The disc has to be perfectly parallel to the lens plane, Make the disc fills most of the frame leave margins all around, Transfer the DV file as is with no processing and upload it here. If you a HDV camcorder, put it in DV 4:3 mode before recording.
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  21. Originally Posted by dellsam34 View Post
    Please do, Shoot about one minute of a black circle like a dark label of a CD on a white background, The disc has to be perfectly parallel to the lens plane, Make the disc fills most of the frame leave margins all around, Transfer the DV file as is with no processing and upload it here. If you a HDV camcorder, put it in DV 4:3 mode before recording.
    Or I can just record a test signal on HDV tape, then output via DV with downconversion set on and it will show if the test pattern will be present in all 720 samples, rather than 702 center ones.
    I'll try that on the weekend.
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  22. Capturing Memories dellsam34's Avatar
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    No, The goal is to test the camcorder imaging sensor frame proportions, HDV should be left out of question, HDV is 1440x1080 16:9 anamorphic, it would no work.
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  23. Originally Posted by dellsam34 View Post
    No, The goal is to test the camcorder imaging sensor frame proportions, HDV should be left out of question, HDV is 1440x1080 16:9 anamorphic, it would no work.
    It is 16:9 anamorphic, yes, but DV can be anamorpic as well. I think it would serve the same purpose, because the camcorder would most likely process both sensor information and downconversion in the same manner, so either compliant, or non-compliant with ITU. So if I recorded a test pattern from PC to tape, then downconverted the tape to DV format it would show how the conversion goes, either into 702 center samples, or 720 samples distorting the image and thus changing the aspect ratio.
    I shall do both then.
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  24. Originally Posted by dellsam34 View Post
    .... I however found that the very late models with higher resolution imaging sensor and the HDV camcorders just format the entire 720 as 4:3. Some people disagreed with me but if I get a hold of one of those camcorders I will do a circle test.
    Interesting. Looking forward to seeing your test. Such cameras would be out of DVCAM spec as I understand.
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  25. Originally Posted by Sharc View Post
    Originally Posted by dellsam34 View Post
    .... I however found that the very late models with higher resolution imaging sensor and the HDV camcorders just format the entire 720 as 4:3. Some people disagreed with me but if I get a hold of one of those camcorders I will do a circle test.
    Interesting. Looking forward to seeing your test. Such cameras would be out of DVCAM spec as I understand.
    Indeed that would be peculiar.
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  26. Member Skiller's Avatar
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    I would not be surprised at all if an HDV camcorder does not stick to the Rec.601 spec when recording DV.
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  27. I will test it on Saturday.
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