4 Replies Latest reply: Feb 24, 2013 6:47 PM by Bob221b1
Bob221b1 Level 1 Level 1 (5 points)

I film with a 6-yr old Sony HD vid cam. As such, it shoots native 1440x1080.  The 1440 of course is measured in .75 pixels, so it comes out as 1920x1080.   Edited in original format (FCP 7) with HDV codec and stored as MPEG-2 very large files.  Chapters included.

 

Those files, under Get Info, measure 1920x1080 and include my chaptering.  Now then:

 

Am archiving those MPEG-2 videos, updating with H264 to save space.  Two ways of doing this are producing two results. 

 

>> Using Compressor/Settings/H264, I get an exported file that appears to play just fine, but (Get info) size is 1440x1080.  It seems apparent that through this method, Compressor keeps the original film format. Am I losing quality over '1920', sq pixels?

 

>> Using QT/ file/export as 1080P, I get the result I'm looking for.. But wonder if the file size is larger.  This same file, perhaps erroneously, measures 1920x1080.

 

It's the same bloody source file, but exported two different ways.

Please explain/offer your opinion on what (IF) is going on, and if there is ANY operational advantage to one over the other:

 

Respectfully,

Bob


Final Cut Pro 7, OS X Mountain Lion (10.8.2)
  • Russ H Level 6 Level 6 (17,040 points)

    In Compressor (3.5?) there are many ways to get an  h,264 transcode and I'm not sure from your description what presets you started with. It is quite possible to produce h.264 files that are quite a bit larger than your MPEG files. (BTW, HDV uses a type of MPEG2 compression scheme, with is why it is reported that way.)

     

    Just speaking to the question of frame size: If your quality settings are comparable, the 1080 frame size (with square pixels) will take up moderately more space on your archive drive than the 1440 frame size (with non-square pixels). I doubt very much that any quality difference will be perceptible.

     

    The broader question is what you hope to achieve in this archiving process. If you simply want a copy that you may want to revisit some day to display on a computer, you can test various settings on short segments to see what quality-size tradeoff is acceptable.

     

    However, if you think there is a possibility that there is a possibility that you would want to re-purpose any of the movie for say, DVD, Blu Ray, the Web, etc, I would consider using the HDV files as your archive.

     

     

    Bob221b1 wrote:

    .   Edited in original format (FCP 7) with HDV codec and stored as MPEG-2 very large files.  Chapters included.

     

     

    HDV is a highly compressed format. It was developed to provide a cost-efficient way of shooting HD and, comparatively speaking it actually produces small files. The HDV files you have now are as high a quality as they can ever be; recompressing – to a different size – to a different data rate – to a different codec – will produce some degree of a quality hit.

     

    H.264 is also a highly compressed format (codec) and produces high quality images at small file sizes. But if you rely on its efficiency to reduce the file size of the MPEG files, you discard digital information that you may need if you ever need to re-purpose them.

     

    BTW, just for kicks I took an excerpt of an HDV 1080i60 (1440X1080) movie and recompressed it to a Quick Time  H.264 100% of source and let the bit rate setting stay at Automatic. The good news is that I was unable to see any degradation in quality; the bad news is my h.264 file was triple the size of my MPEG.

     

    So. again, I suggest you experiment with settings and evaluate the output to see whether it's satisfactory for your present and future needs.


    Good luck.

     

    Russ

  • Bob221b1 Level 1 Level 1 (5 points)

    Hi Russ,

     

    Thanks.. Another question please..

     

    Those same films, with embedded FCP-7 produced Chapters.. Having an issue with Compressor:

     

    When I import a movie, say, HDV.. and use Compressor to export using the H264 preset, the result is a file 1/3 the size, but the chapters are gone!  Compressor is eliminating them when encoding/exporting.. Etc.

     

    However:  if I use QT to export as 1080P, those files are still H264/AAC/Text (under get info), but ALSO KEEP THE CHAPTERS. 

     

    Compressor has so many export choices (Presets), including H264... an several in a batch makes keystrokes easier, but ****!, why are the chapters not retained as with QT//Export/H264????

     

    >> How can Compressor be made to export a .mov with H264 AND not drop the chapters.  The files WERE IMPORTED with perfectly good chapters!

     

    Will also submit under a new topic.

     

    Thanks in advance..Bob

  • Russ H Level 6 Level 6 (17,040 points)

    Again, I'm not sure what kind of H.264 preset you're starting with in Compressor…please post a screen shot of the Encoder panein the Inspector. Some formats recognoze chapter markers and some don't. SO if we could better see how you're working, we may be able to give you some ideas.

     

    Russ

  • Bob221b1 Level 1 Level 1 (5 points)

    Hi Russ,

     

    I don't know how I did it.. But I fooled around with Compressor and got the chapters to work.

    Just wanted to give you feedback since you took out time to try to help.

     

    If you want to tackle another issue.. Lol, I just posted under FCP7 with respect to my new Sony HD camera I purchased.

     

    Respectfully,

    Bob