Quantcast BetacamSX archiving project - digitalFAQ Forum
  #1  
07-12-2019, 02:34 PM
nesburf nesburf is offline
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Hi all

I have a massive archiving project I am working on. I have over 1000 BetacamSX tapes that I need to digitize and archive in the XDCAM EX format.

I have access to Sony DNW-A75 decks and Harris X50 frame syncs. I also have a Blackmagic Ultrastudio Pro USB 3.0 capture device I have been playing around with. I have been able to capture video in the XDCAM EX format using ffmpeg however no matter what I try, I cannot get the audio and video in sync. It is always off by a few frames. I have scoured the internet and looked at all the ffmpeg mailing lists and for the life of me cannot get it to work. I have seen a lot of posts regarding sync issues however I have not been able to find a solution. I have a feeling it's an issue with this capture device.

I can capture using the BM Media Express software and the audio is in sync, however it only records to either uncompressed avi/mov or the MJPG format. I really would like to capture directly to XDCAM EX so I do not have to process the video further.

Does anyone have any suggestions on capture cards or a good workflow to make this work?
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  #2  
07-12-2019, 04:32 PM
hodgey hodgey is online now
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Betacam SX is a digital format, so there shouldn't really be sync issues, or at the very least there would only be an offset and not vary over time. The capture card shouldn't really matter if you are capturing SDI.

Did you try virtualdub? It can't capture directly to a to spec XDCAM file but you may be able to capture with the right video codec to an .avi, or at least to a lossless intermediate.

The deck can output the raw data stream over SDTI if it has the right addon card. I am not familiar with the software/hardware used for that but that would be the idea method if possible as it would give you a direct copy of the data on tape and keep it in the original compressed format. Granted, you may still need a lossy conversion to get it into the right XDCAM format.
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  #3  
07-12-2019, 04:35 PM
NJRoadfan NJRoadfan is offline
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How are you capturing the video? Betacam SX is natively digital. Best way to capture would be to run the SDI output from the deck into a SDI capture device, which can be had relatively cheaply these days. From there you should be able to capture to XDCAM EX.
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  #4  
07-12-2019, 04:52 PM
nesburf nesburf is offline
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Thanks for the quick replies. I understand SDI is a digital and audio sync shouldn't be an issue. I believe the sync problems are created between ffmpeg and the BM UltraStudio Pro USB3 device.

I have been capturing using this ffmpeg string

Code:
ffmpeg -f dshow -video_size 1920x1080 -pixel_format uyvy422 -rtbufsize 702000k -framerate 29.97 -i video="Decklink Video Capture":audio="Decklink Audio Capture" -pix_fmt yuv420p -vcodec mpeg2video -flags +ildct+ilme -top 1 -dc 10 -qmin 1 -lmin "1*QP2LAMBDA" -vtag xdv3 -b:v 35000k -minrate 35000k -maxrate 35000k -bufsize 36408333 -g 15 -bf 2  -acodec pcm_s16le -filter_complex "[0:a]channelsplit[l][r]" -map 0:v -map "[l]" -map "[r]" -f mxf -y "output.MXF"
My video and audio are always out of sync by a few frames. I've made test tapes to verify the sync.

I'm looking at testing out a Blackmagic Decklink Duo 2 card to see if it will work. It would also give me up to 4 inputs.

I would like to capture directly to XDCAM EX as I don't want to deal with further transcoding/encoding.

EDIT: I also tried this command using the built in decklink function of ffmpeg and got a similar result with OOS audio.

Code:
ffmpeg -f decklink -i "UltraStudio Pro" -pix_fmt yuv420p -vcodec mpeg2video -flags +ildct+ilme -top 1 -dc 10 -qmin 1 -lmin "1*QP2LAMBDA" -vtag xdv3 -b:v 35000k -minrate 35000k -maxrate 35000k -bufsize 36408333 -g 15 -bf 2 -acodec pcm_s16le -ar 48000 -filter_complex "[0:a]channelsplit[l][r]" -map 0:v -map "[l]" -map "[r]" -f mxf -y "output.MXF"

Last edited by nesburf; 07-12-2019 at 05:04 PM.
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  #5  
07-12-2019, 05:21 PM
hodgey hodgey is online now
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Code:
-vsync 0
May or may not help,
You could also try with
Code:
-af aresample=async
which streches audio samples to align with video.

Another option, if the audio offset is always constant and the same on each tape you could simply add an audio offset e.g with
Code:
-af atrim=start=2
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  #6  
07-12-2019, 08:45 PM
latreche34 latreche34 is offline
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XDCam and Betacam SX are storage formats not video formats, I don't know what do you mean by capturing to XDCam EX?

Betacam SX uses MPEG-2 SD 4:2:2 @ 18 MB/s (720x480) for NTSC, 4 ch 48Khz/16bit audio. XDCam EX uses MPEG-2 HD 4:2:0 and employs a different compression scheme HQ @ 35MB/s (1920x1080) and SP @ 25MB/s (1440x1080), Not sure what's the audio format but I assume PCM 2-4 channels.

So I don't know how possible is to capture, change the video format, and format in XDCam EX disc image in one single step.
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  #7  
07-15-2019, 11:04 AM
nesburf nesburf is offline
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Quote:
Originally Posted by latreche34 View Post
XDCam and Betacam SX are storage formats not video formats, I don't know what do you mean by capturing to XDCam EX?

Betacam SX uses MPEG-2 SD 4:2:2 @ 18 MB/s (720x480) for NTSC, 4 ch 48Khz/16bit audio. XDCam EX uses MPEG-2 HD 4:2:0 and employs a different compression scheme HQ @ 35MB/s (1920x1080) and SP @ 25MB/s (1440x1080), Not sure what's the audio format but I assume PCM 2-4 channels.

So I don't know how possible is to capture, change the video format, and format in XDCam EX disc image in one single step.
XDCAM EX is technically a codec, or essentially a form of MPEG2 compression.

What I would like to do is playback my SX tapes over SDI, use an SDI capture card and encode the incoming stream to XDCAM EX which is essentially 35mbps MPEG2 compression in the MXF container. This can be done via ffmpeg, I am just having trouble with audio sync issues.
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  #8  
07-15-2019, 12:13 PM
nesburf nesburf is offline
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Quote:
Originally Posted by hodgey View Post
Code:
-vsync 0
May or may not help,
You could also try with
Code:
-af aresample=async
which streches audio samples to align with video.

Another option, if the audio offset is always constant and the same on each tape you could simply add an audio offset e.g with
Code:
-af atrim=start=2
Tried both vsync and aresample options and neither make any difference.
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  #9  
07-15-2019, 01:13 PM
latreche34 latreche34 is offline
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Did you try Sony and Adobe software? They can capture from SDI and they can output as XDCAM as far as I can remember.
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  #10  
07-15-2019, 02:14 PM
nesburf nesburf is offline
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Quote:
Originally Posted by latreche34 View Post
Did you try Sony and Adobe software? They can capture from SDI and they can output as XDCAM as far as I can remember.
Adobe will only capture to uncompressed, DNxHD or MJPEG. Vegas will only capture to XDCAM HD which is not ideal.

I was really hoping to make ffmpeg work as I can get the exact codec I want. Maybe I will give another decklink card a try.
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  #11  
07-15-2019, 09:07 PM
cbehr91 cbehr91 is offline
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Like others have said BetaSX is already digital. I am in a similar boat to you as I have hundreds, perhaps thousands of DVCPRO and MiniDV camera tapes that I am in the process of capturing (digitize would not be the proper word since it's a digital format). I have a Blackmagic Decklink Mini Recorder -- a very simple PCI capture card with just SDI and HDMI inputs. It took some doing, but I got the card to work with VirtualDub and am capturing with the Cedocida DV Codec (don't use this codec for BetaSX). You probably could capture the SDI out on the BetaSX to Huffyuv or UT Video using the same method. Otherwise, DNxHD, uncompressed, or M-JPEG capture with Adobe or the Blackmagic software are it.
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  #12  
07-15-2019, 10:27 PM
NJRoadfan NJRoadfan is offline
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DVCPRO and MiniDV should be captured using Firewire (its WAY easier that way!).

As for the Betacam SX work. I would capture from SDI to whatever works (something tells me that VirtualDub to a lossless format intermediate would be fine, or try AmaRecTV 3.10 as it seems to handle fussy capture cards) then use a batch script and ffmpeg to compress to whatever format you want. SDI really shouldn't have audio sync problems as I believe it has "locked" audio like DV does. Keep in mind that XDCAM EX is usually a HD format. Most references to XDCAM for SD video state its MPEG-2 422P@ML stored in a mxf container (MPEG IMX).
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  #13  
07-16-2019, 02:40 AM
latreche34 latreche34 is offline
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Quote:
Originally Posted by cbehr91 View Post
Like others have said BetaSX is already digital. I am in a similar boat to you as I have hundreds, perhaps thousands of DVCPRO and MiniDV camera tapes that I am in the process of capturing (digitize would not be the proper word since it's a digital format). I have a Blackmagic Decklink Mini Recorder -- a very simple PCI capture card with just SDI and HDMI inputs. It took some doing, but I got the card to work with VirtualDub and am capturing with the Cedocida DV Codec (don't use this codec for BetaSX). You probably could capture the SDI out on the BetaSX to Huffyuv or UT Video using the same method. Otherwise, DNxHD, uncompressed, or M-JPEG capture with Adobe or the Blackmagic software are it.
You don't really have to go that way, If you don't have a firewire port on your computer just get a used Pinnacle USB-500 and connect the camcorder/DV deck to the firewire port of the USB-500 box and your computer to the USB port of the USB-500 and transfer the raw footage to your computer, The device is USB powered. A PCI Firewire card though is ideal since you have a desktop.
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  #14  
07-16-2019, 05:19 PM
nesburf nesburf is offline
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I am well aware SX is already digital. The point is that SDI is essentially an uncompressed signal that has to be dealt with upon capture. I wanted to capture/encode at the same time so I wouldn't have to do further processing afterwards. I have the SX deck going into an X50 to do the upconvert so I have an HD 1080i signal going into the BM device. I can get a working XDCAM EX MXF file albeit with sync issues. At this point I'm convinced it's the USB BM device that is causing the issue so I think I'm going to look into one of the Decklink Duo cards.
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  #15  
07-16-2019, 07:04 PM
NJRoadfan NJRoadfan is offline
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Why are you needlessly upconverting SD footage to HD?

Personally I would avoid any of the Black Magic devices for this task, they are well known for being troublesome. Just get a cheapo SDI to USB (or PCIe) card that has DirectShow drivers and capture the 480i video direct from the deck via SDI. When it comes to capture the KISS principle applies.
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  #16  
07-16-2019, 07:08 PM
nesburf nesburf is offline
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Quote:
Originally Posted by NJRoadfan View Post
Why are you needlessly upconverting SD footage to HD?

Personally I would avoid any of the Black Magic devices for this task, they are well known for being troublesome. Just get a cheapo SDI to USB (or PCIe) card that has DirectShow drivers and capture the 480i video direct from the deck via SDI. When it comes to capture the KISS principle applies.
So my original plan was to capture 480i and archive in SD. However, I'm in a broadcast environment, and these will be eventually archived onto LTO tape on an in house developed archive server. The server is set up only to handle XDCAM50 or XDCAM EX. This is done to standardize all footage across many stations. So I have to somehow get my footage into the XDCAM format in the easiest way possible.
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