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ProRes 720x486 Black Lines

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John Michaels
ProRes 720x486 Black Lines
on Dec 7, 2015 at 6:23:30 pm
Last Edited By John Michaels on Dec 7, 2015 at 6:27:09 pm

Hello, hoping for a sanity check here.

I'm taking a lot of 1080p 23.976 HD masters and center cutting them down to 720x486 23.976 SD ProRes files (just following orders). When I do this, I get black lines at the top and bottom of the frame.

Now, my understanding is that these black lines should be there; it's the VBI, correct? My files keep getting rejected by the powers that be, because of those black lines. However, the client is also explicitly asking for 486 and not 480 so I can't just go that route.

I did notice that if I bring the files in to Final Cut Pro or view them in Quicktime 7, that the black bars remain, instead of being somehow "hidden" as would happen with another SD format such as IMX50. Is it possible this is just a metadata issue of some sort?

Attached is a frame grab, and below is a mediainfo readout of the file:



General
Complete name : /Users/JohnMichaels/Desktop/test.mov
Format : MPEG-4
Format profile : QuickTime
Codec ID : qt
File size : 53.2 GiB
Duration : 2h 6mn
Overall bit rate mode : Variable
Overall bit rate : 60.2 Mbps
Encoded date : UTC 2015-11-23 17:45:58
Tagged date : UTC 2015-11-23 17:45:58

Video
ID : 2
Format : ProRes
Format version : Version 0
Format profile : 422 HQ
Codec ID : apch
Duration : 2h 6mn
Bit rate mode : Variable
Bit rate : 48.6 Mbps
Width : 720 pixels
Clean aperture width : 720 pixels
Height : 486 pixels
Clean aperture height : 486 pixels
Display aspect ratio : 4:3
Clean aperture display aspect ratio : 4:3
Frame rate mode : Constant
Frame rate : 23.976 fps
Color space : YUV
Chroma subsampling : 4:2:2
Scan type : Progressive
Bits/(Pixel*Frame) : 5.798
Stream size : 43.0 GiB (81%)
Title : Telestream Inc. Telestream Media Framework - Release TXGP 2015.12.176624
Writing library : apt0
Encoded date : UTC 2015-11-23 17:45:58
Tagged date : UTC 2015-11-23 17:45:58
Color primaries : BT.601 NTSC
Transfer characteristics : BT.709
Matrix coefficients : BT.601
matrix_coefficients_Original : BT.601

Audio
ID : 3
Format : PCM
Format settings, Endianness : Little
Format settings, Sign : Unsigned
Codec ID : in24
Duration : 2h 6mn
Bit rate mode : Constant
Bit rate : 11.5 Mbps
Channel(s) : 10 channels
Sampling rate : 48.0 KHz
Bit depth : 24 bits
Stream size : 10.2 GiB (19%)
Title : Telestream Inc. Telestream Media Framework - Release TXGP 2015.12.176624
Language : English
Encoded date : UTC 2015-11-23 17:45:58
Tagged date : UTC 2015-11-23 17:45:58

Other
ID : 1
Type : Time code
Format : QuickTime TC
Duration : 2h 6mn
Time code of first frame : 00:57:30:00
Time code, striped : Yes
Title : Telestream Inc. Telestream Media Framework - Release TXGP 2015.12.176624
Language : English
Encoded date : UTC 2015-11-23 17:45:58
Tagged date : UTC 2015-11-23 17:45:58
Bit rate mode : CBR


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Craig Seeman
Re: ProRes 720x486 Black Lines
on Dec 7, 2015 at 7:18:05 pm
Last Edited By Craig Seeman on Dec 7, 2015 at 7:21:08 pm

Quicktime 7 Player (and Frameworks) are deprecated.

Please test in Telestream Switch 2.0.1 and Quicktime X.
Please explain exactly what your settings are in the Resize Filter (be complete).
What version of Episode are you using (current is version 7).
Also please do describe intended use of the encoded file.



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John Michaels
Re: ProRes 720x486 Black Lines
on Dec 7, 2015 at 7:22:45 pm

Same thing in Switch an Quicktime X.

I'm doing this in Vantage (not Episode) using the Quicktime (Telestream) encoder. For my Resize filter, I've tried both "Crop (Center Cut)" and Manual, with 0 crop and padding on top and bottom, and 240 pixel crop in from left and right. Both resize settings yield the same result. I do have the VBI settings enabled (which is the default) for 4 upper and 2 lower. I'm sure disabling this (setting it to full frame active picture) would get rid of the bars, but again, aren't they supposed to be there for 486 material?


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Craig Seeman
Re: ProRes 720x486 Black Lines
on Dec 8, 2015 at 5:00:42 am

[John Michaels] "I'm sure disabling this (setting it to full frame active picture) would get rid of the bars, but again, aren't they supposed to be there for 486 material?"

I think you should get rid of the bars especially if that's what they want. As to the 6 lines, HD to SD conversion can involve going to 720x480 source and one would need to add the lines (4 on top, 2 bottom as you mention) to get a 486 standard for broadcast. Those lines wouldn't be visible due to TV overscan.That wouldn't be VBI though. It its not for broadcast it can be left at 720x480 (DVD for example).

This is why I wonder what the intent is. Might there be a next stage where someone will add pull down frames and interlace? If it's for DVD use 720x480 would be fine. In fact one might do 720x480 anamorphic for SD 16x9 to keep the aspect ratio.

VBI would be 720x512. This is how I would deliver SD broadcast spots back in the day to DGFastchannel for distribution.



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