Convert High Definition to Standard Definition Video

Posted on by Larry

One of the questions I’m getting asked more and more is how to convert HD video into SD video. SD versions are necessary for creating DVDs, to send to a cable outlet that has not yet upgraded to HD transmission, or for any of a number of perfectly valid reasons. Making this even more complex is converting between 16:9 and 4:3, or, even converting frame rates.

Keep in mind that when you convert HD to SD, your image quality will degrade. Always. SD is 1/7th the image quality of HD. SD images will NEVER look as good as HD. That’s why they invented HD.

Also, DVD Studio Pro can not create DVDs containing high-def video. Instead, the format it creates – HD-DVD – died many years ago. Nor can you use DVD Studio Pro to create Blu-ray Discs.

In this article, I’ll show you how to export a master movie, and how to convert it to SD. At which point, you can compress it for DVD, or deliver it for broadcast, or… whatever.

DEFINITION: Transcode means to convert from one file format to another. In my mind when I am transcoding, I am converting from one editable format to another. When I am compressing, I am creating the final compressed version to post to the web. In my mind, transcoding always yields higher quality, but larger file sizes, than compressing. This definition is not totally accurate. Purists would argue that the two terms are essentially synonyms. That is probably true, however, they have different shades of meaning to me.

TOOLS

In this article, I’ll use Apple Compressor, because it is optimized to create QuickTime files and is inexpensive.

However, you can also use Sorenson Squeeze or Telestream Episode, if you have them installed on your system. The benefits to this software is support for far more video formats, faster performance, and a different way to automate file handling: watch folders.

One application that I prefer not to use for transcoding is Adobe Media Encoder (AME). While I truly enjoy working with other Adobe applications, AME is designed for compressing files for final delivery, not creating high-quality intermediate files. I find using it is an exercise in frustration, which is a shame because it is so nicely integrated with Premiere.

SOME BACKGROUND

Whenever you are handling a file multiple times, you want to work at the highest-possible quality so that repeated manipulations do as little damage to the file as possible. Files that are created after you export a master file and you compress the final version for the web are called “intermediate” files.

In our case, we will create an intermediate SD file using Apple ProRes 422. ProRes offers a great balance between file size, image quality, and minimal compression. I prefer it for almost all my work.

CREATE THE MASTER FILE

If you need to create a master file from your software, follow the instructions in this section. If you are given a master file, jump down to the next section.

Whether you are using Final Cut Pro 7 (or earlier), Final Cut Pro X, or Adobe Premiere Pro CS6, this process starts by creating a high-quality, self-contained, master file.

NOTE: All this software can transcode projects into an intermediate SD file. However, I’ve never liked the quality nor the time it takes. I prefer to create a high-quality master file, then convert it using a dedicated compression program, rather than rely on the editing software for the conversion.

In Final Cut Pro 7, select the sequence you want to export in the Browser, then choose File > Export > QuickTime Movie (or type Command+E).

In the resulting dialog box:

When you click Save, FCP 7 exports a file that matches the sequence settings of your project and creates a self-contained QuickTime movie. This file may, or may not, be a ProRes file. At this point, we don’t care. Matching your sequence settings is both the fastest and best way to get a file out of Final Cut Pro 7.

NOTE: In the past, we could create two types of movies: reference and self-contained. Reference files were smaller and faster to export, but they simply pointed to your source and render files. If even one of these referenced files was lost or moved, the entire movie would break. Self-contained files are bigger and take longer to export. However, they are complete in themselves and can be played anywhere on anything.

In Premiere Pro CS6, select the sequence to export in the Project tab. Then, choose File > Export > Media (or type Command+M).

In the Export Settings window:

This creates a stand-alone file that matches your sequence settings. In most cases, this won’t be a ProRes file. Again, don’t worry about that.

In Final Cut Pro X, display the Project Browser and select the Project you want to output.

Choose File > Share > Master File, or type Command+E (this keyboard shortcut may not work for all versions of FCP X).

In the Master File screen, click the Settings tab and verify:

Click Next.

Give the file a name and location, then click Save.

Regardless of the software you used, you’ve now created a high-quality master file, ready to compress.

CONVERTING HD TO SD

Here’s the first thing you need to know about compression: Never, ever worry about the file size or format of your source master file. You only need to define what you want the file to become. The compression software will handle all necessary conversion.

In Compressor, click the Add File icon at the top and add your master file. (in this example, I’m using a 1920 x 1080 file, complements of Pond5.)

In the Search box at the top of the Settings window, type “Prores” — you don’t need to press Tab. As soon as you type the word, five options appear in the Settings window below.

Drag the top choice – ProRes 422 – on top of the master file you imported into the top left window of Compressor. This tells Compressor what format you want the transcoded file to have.

Right-click the middle column in the Task window, to set a destination. By default, Compressor stores the compressed file in the same location as the source file. On my system, I’ve created a new folder specifically to store all my compressed files. (Here’s an article that describes that process.)

You can also select Custom to set a custom destination for the transcoded intermediate file. In this example, I’ll leave the destination set to Compressed Files, which is the custom destination that I created.

A NOTE ON INTERLACING

Interlacing is the bane of video posted to the web, but required for all SD formats and some HD formats.

The good news is that if you shot 1080i, the process of creating an SD version automatically removes all interlacing. Always. All the time. So you never have to deinterlace as part of editing your project. And all 720p formats are interlace-free.

Basically, when converting HD to SD, you never worry about deinterlacing. Your final file will always look good, and it won’t contain interlace lines..

CHANGING THE IMAGE SIZE

SD is not the same  frame size as HD. To change the frame size, select the Apple ProRes 422 codec this is applied to the movie. (Don’t select the movie, you need to select the codec applied to the movie.)

Then, in the Inspector, click the Geometry tab, this allows us to change the size of the compressed image. (Remember, we never worry about the source file, only what we want it to become.)

Now things get complex, depending upon where you need to deliver your video.

Convert a 16:9 master file to PAL 4:3

Convert a 16:9 master file to PAL 16:9

Convert a 16:9 master file to NTSC 4:3 – this works for DVD, cable, or broadcast.

Convert a 16:9 master file to NTSC 16:9

NOTE Broadcast 4:3 image sizes are actually 720 x 486. However, when those six lines are missing, broadcast gear centers the image vertically and inserts black lines at the top and bottom. Since these black lines are far outside Action Safe they won’t be seen on home TV sets.

CHANGING FRAME RATE

This is, potentially, the most tricky, because some frame rates convert perfectly and others don’t. In general, if you need to create a PAL master, shoot 25 or 50 fps. If you need to create an NTSC master, shoot 29.97, 30, 59.94, or 60 fps.

Other combinations can be converted, but will often cause image stuttering. this is one of those examples where you need to keep your final master in mind when you shoot.

NOTE: If you shot the wrong frame rate, but need to create the absolutely smoothest playback, check into renting time on an Amberfin system. This software, which is not cheap, will do the best job of retiming video. Most high-end past facilities will have access to this software.

To change frame rates, click the Encoder icon in the Inspector. Then, click the Settings button next to Video.

NOTE: The Audio setting should be grayed out and set to Pass-Through. This means that your audio is simply copied without any changes from the master file to the transcoded file. In almost all cases, this is the best choice.

In the Standard Compression Settings window, set the frame rate to:

The rest of the settings are fine. Click OK.

MAKE IT SO

Click Submit to send your file to the last stage.

Then, click Submit a second time to send it off to compress. (The Name field allows you to enter a batch name. This has nothing to do with the name of the compressed file.)

Now that you’ve configured this setting, you can either save it as a preset if you want to use it again, or, even, convert it into a Droplet. (This article describes how to create a droplet.)

Whew. That was a lot of steps, but, it gets easier each time you do it.

 


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50 Responses to Convert High Definition to Standard Definition Video

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  1. John Cole says:

    OK, I just made an attempt
    HD 1920×1080, 23.98 NTSC to Pal SD 25 4:3
    Didn’t try playback because the image was squished long and tall – what did I do wrong?

    thank you!

    • Larry says:

      John:

      First, convert 23.976 fps to 25 is less of a problem than converting 25 to 23.976. My guess is that you should be OK.

      In order to avoid squishing your video, you need to use the Cropping & Padding dialog. Re-read the article again and check your settings.

      Larry

  2. It would be nice if you updated this tutorial, Larry. Menus and layout change all the time in Apple’s software.

    • Helge:

      True, the interfaces evolve, but the settings they use don’t.

      I’d love to update all my articles, but with more than 2,000 on file there just isn’t time. I’ll see if I can create a new article about this in the near future.

      Larry

  3. Hi Larry,

    I’m writing with 2 items. The first is an observation, the second an enquiry.

    1. Today I used my normal settings to create a PAL 169 SD submaster from a 1920 x 1080p master created as per your excellent article. In the distant past I think it worked fine but today the generated file was 1490 x 576 instead of the 1024 x 576 I was expecting. Several attempts and re-readings later I was none the wiser. However, I worked out that if I used 720 x 576 and left the pixel ratio as Square instead of CCIR 601, the resulting anamorphic file is perfectly usable as a 1024 x 760 file.

    2. Chapter markers in Compressor. The above files will eventually end up in DVDSP and I thought to save time by applying Chapter markers in FCPX. However when I got them converted to SD and imported them into FCP 7 (which is how I create my DVDSP files because its more reliable for me) the files were the correct length but only 16 frames appeared right at beginning (the rest of the file is just black) and each frame matches the frame I selected for the placing of the chapter markers i.e. I have 16 chapters.

    Long shot, I fear, but any ideas?

    • Larry says:

      Ian:

      1. You are correct, 1024×576 is the square pixel version of 720×576. PAL pixels are short and fat, not squares.

      2. I suspect you are using a codec that isn’t supported by FCP 7. Try exporting as ProRes 422 with Chapter Markers and see if that works better.

      Larry

      • Ian Colquhoun says:

        Thank you so much for the prompt reply.

        It was a Prores 422 codec that I was using. As I suspected, by deleting the chapter markers from the original FCPX timeline ad re-exporting, firstly as an HD Master then converting that to an SD submaster I was able to ingest into FCP 7 with no problems.

        Now, if I could just work out what is going on… 🙂

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