Answers.Body: <p>Containers like LXF/GXF/MXF allow EIA-708 (VBI) streams but as far as I know they do not encode the video data -- the blanking interval -- that originally contained those streams. That would run counter to the idea that codecs embody, that of squeezing out redundant information. I could be wrong, but I've never seen or heard of a codec that encodes invisible lines.</p>
  
  <p>You could scan the file for the packet headers that identify caption / VBI streams, and if you find them you could impute a frame size that would have contained them, but you could do that anyway: any encoded video, if it were output as a TV signal, would have associated blanking, whether it contained captions or not.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2015-08-09T14:01:08.517Z
Answers.Text: These are SD files. I.e Eia 608.  You can read more here https://en.m.wikipedia.org/wiki/EIA-608
Answers.UserDisplayName: Johan Skaneby
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2015-08-09T14:03:46.460Z
Answers.Text: You can read about EIA 608 here https://en.m.wikipedia.org/wiki/EIA-608
Answers.UserDisplayName: Johan Skaneby
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2015-08-09T14:04:38.620Z
Answers.Text: So back to the original question - how to detect the presence of these lines?  which tool?
Answers.UserDisplayName: Johan Skaneby
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2015-08-09T15:50:39.617Z
Answers.Text: @JohanSkaneby Your question is about **lines** and **frame size** which are the wrong questions. These lines do not exist as video and do not affect the frame size. Only the data carried in those lines is stored in the container, alongside the video. Google "LXF VBI data" and you'll find pointers to tools that can find and read this data. It's a question of opening the file and scanning for headers.
Answers.UserDisplayName: Jim Mack
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2015-08-09T16:03:58.830Z
Answers.Text: What about line 21 and line 22?
Answers.UserDisplayName: Johan Skaneby
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2015-08-09T16:08:21.663Z
Answers.Text: Ok - anyway tnx for your time. We do not agree on basic technical background to my question. And Google for the answer is of course one of the ways to find the answer ;-)
Answers.UserDisplayName: Johan Skaneby
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2015-08-09T17:36:03.670Z
Answers.Text: @JohanSkaneby Lines 21 & 22 are not considered part of active video and are not usually digitized. If they contain data it can be extracted and encoded as a separate stream. I had no difficulty locating tools via Google to examine LXF VBI streams, so yes, Google is your friend.
Answers.UserDisplayName: Jim Mack
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2015-08-09T13:56:35.580Z
Answers.LastActivityDate: 2015-08-09T13:56:35.580Z
Answers.UserDisplayName: Jim Mack
Body: <p>Is there a way to detect if a file has or has not Vbi data this way! 
  I.e if a Pal videofile with the reported 720x576 has Vbi data the actual height is an additional 32 lines = 608.</p>
  
  <p>SD pal file VBI = 720x608 </p>
  
  <p>I am not interested in the info in those 32 lines - I just want to know if they are present or not ( to be able to make an decicion)</p>
  
  <p>So far from what I can see ffmpeg and Medialinfo reports my VBI samples as 720X576 - but I know they are 608. </p>
  
  <p>Maybe I am using the wrong tools or the wrong flags / cli arguments? </p>
  
  <p>Many tnx!</p>
  
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2015-08-08T17:20:38.560Z
Comments.Text: It would be very unusual for the horizontal and vertical blanking to be included in an encoded digital file. Why do you believe that these files have that information?
Comments.UserDisplayName: Jim Mack
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2015-08-08T17:45:45.243Z
Comments.Text: Because fx Carbon detects the  file as 720x608 - and will output these lines unless I crop of 32 lines on the top. ( Carbon has an automatic detection / crop also - because other workflow Considerations I can't use that)
Comments.UserDisplayName: Johan Skaneby
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2015-08-09T12:51:44.763Z
Comments.Text: Sorry to be dense, but are you talking about a digital file on disk? If so, what type is it (container and codec)?
Comments.UserDisplayName: Jim Mack
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2015-08-09T13:03:56.793Z
Comments.Text: Yes - we are talking about a digital file, correct. So far LXF and Mxf. long gop Mpeg 2 inside
Comments.UserDisplayName: Johan Skaneby
Tags: <video><ffmpeg>
Title: Detecting VBI or true video height?
UserDisplayName: Johan Skaneby
ThreadText: # Detecting VBI or true video height?
  
  (Asked by: username_0 on 2015-08-08)
  
  Is there a way to detect if a file has or has not Vbi data this way!
  I.e if a Pal videofile with the reported 720x576 has Vbi data the actual height is an additional 32 lines = 608.
  
  SD pal file VBI = 720x608
  
  I am not interested in the info in those 32 lines - I just want to know if they are present or not ( to be able to make an decicion)
  
  So far from what I can see ffmpeg and Medialinfo reports my VBI samples as 720X576 - but I know they are 608.
  
  Maybe I am using the wrong tools or the wrong flags / cli arguments?
  
  Many tnx!
  
  **Tags:** video, ffmpeg
  
  > **Comments:**
  > **username_1**: It would be very unusual for the horizontal and vertical blanking to be included in an encoded digital file. Why do you believe that these files have that information?  
  > **username_0**: Because fx Carbon detects the  file as 720x608 - and will output these lines unless I crop of 32 lines on the top. ( Carbon has an automatic detection / crop also - because other workflow Considerations I can't use that)  
  > **username_1**: Sorry to be dense, but are you talking about a digital file on disk? If so, what type is it (container and codec)?  
  > **username_0**: Yes - we are talking about a digital file, correct. So far LXF and Mxf. long gop Mpeg 2 inside  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_1 on 2015-08-09. Score: 1
  
  Containers like LXF/GXF/MXF allow EIA-708 (VBI) streams but as far as I know they do not encode the video data -- the blanking interval -- that originally contained those streams. That would run counter to the idea that codecs embody, that of squeezing out redundant information. I could be wrong, but I've never seen or heard of a codec that encodes invisible lines.
  
  You could scan the file for the packet headers that identify caption / VBI streams, and if you find them you could impute a frame size that would have contained them, but you could do that anyway: any encoded video, if it were output as a TV signal, would have associated blanking, whether it contained captions or not.
  
  > **Comments:**
  > **username_0**: These are SD files. I.e Eia 608.  You can read more here https://en.m.wikipedia.org/wiki/EIA-608  
  > **username_0**: You can read about EIA 608 here https://en.m.wikipedia.org/wiki/EIA-608  
  > **username_0**: So back to the original question - how to detect the presence of these lines?  which tool?  
  > **username_1**: @username_0 Your question is about **lines** and **frame size** which are the wrong questions. These lines do not exist as video and do not affect the frame size. Only the data carried in those lines is stored in the container, alongside the video. Google "LXF VBI data" and you'll find pointers to tools that can find and read this data. It's a question of opening the file and scanning for headers.  
  > **username_0**: What about line 21 and line 22?  
  > **username_0**: Ok - anyway tnx for your time. We do not agree on basic technical background to my question. And Google for the answer is of course one of the ways to find the answer ;-)  
  > **username_1**: @username_0 Lines 21 & 22 are not considered part of active video and are not usually digitized. If they contain data it can be extracted and encoded as a separate stream. I had no difficulty locating tools via Google to examine LXF VBI streams, so yes, Google is your friend.  
  
  ---
  
  