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Discovered a way to get better (smoother) 1080p MP4s from 1080i footage in Avid MC
I’ve read from Creative Cow for years, but have never had reason to post until today. I’m a bit nervous that this is a fairly well known work around, and I’m just that slow in the head, but here goes. My apologies for what is a long, and likely hard-to-follow, post about creating smoother looking 1080p MP4 files from a 1080i source in Avid Media Composer. There’s a short version at the very end for those with little patience or for those that can’t follow my writing style.
Preface: I work for a small community college and have only upgraded our production equipment and to HD within the last year. Since then, we’ve shot everything in 1080i-59.94 to prepare for our cable station head-end upgrade, which will happen in August.
Problem: As many of you have experienced, creating 1080p MP4 files for use on YouTube (and other web sources) from a 1080i source has produced disappointing results. We typically would create a Quicktime Reference file from the Avid and then render MP4 content using Sorenson Squeeze 9. (We’d render MP2 files for DVD at the same time, which was a whole different set of problems.) What we were getting was either the interlace lines showing up in the footage (naturally) and also footage that seemed shuttered. Even when using the deinterlace tools inside of SS9, we never were able to lose the shuttered look. The movement wasn’t as smooth as it appeared when watching the confidence monitors while editing. See an example of this below.
As we get closer to the install of our head-end, we decided to do some tests with 720p footage to see if we were happier with the results. Again as many of you have experienced, the 720p footage produced much more satisfying results. The result had the smoothness we expected when compared to what we saw in the confidence monitors and without the interlace lines.
That left us with the problem of what to do with the entire catalog of b-roll footage we’ve shot over the last year. As part of the testing, we brought the AMA linked 1080i footage into a 720p-60 project and went through the export and render process, and the result was the same smoothness as the confidence monitor and surprisingly, no interlace lines.
Since using the 1080i footage in the 720p-60 project worked so well, we decided to see what would happen inside of a 1080p-60 project. We took the same 1080i footage and threw a few clips together on a timeline and went to export it. Though the process of the export needed to change (more on that below), the resulting MP4 didn’t show the interlace lines, nor did it have the same shuttered look. We had the same experience opening 1080i sequences that have been mixed-down.
Our solution and process for existing 1080i-59.94 projects:
1) Project shot and edited in 1080i-59.94.
2) Mixdown the sequence in the 1080i-59.94 project. I typically have a separate bin for mixed files/sequences.
3) Open a new project at 1080p-60, and open the bin containing the mixed-down files & sequence.
Avid will need to modify the sequence to reflect the new framerate and scanning.
This is where we found our first “hitch.” Avid (or Quicktime) can’t create a Quicktime Reference file of a “larger than HD” sequence. We had to create a new export setting.
4) Export the new 1080p-60 sequence using the Avid DNxHD 1080p-30 setting. (They don’t offer an export using 60p, and for whatever reason 30p works and looks “right.”)
5) Take the resulting sequence.mov file into Sorenson Squeeze and import it into Sorenson Squeeze 9. We just used the YouTube_1080p preset, but you can use an increased bitrate or whatever MP4 settings you require.
The crazy thing is that trying to use the same export setting in the 1080i project leaves the interlace lines. So, there’s something that happens when Avid resamples? / upconverts? the 1080i footage into a progressive scan project that doesn’t happen in Sorenson Squeeze, or in any other program that would import the Quicktime Reference file. Sony Vegas was the closest to creating what we wanted to see, but even that left a bit to be desired.
The downside is that the process takes more hard drive space, and adds quite a bit of render time. We only came across this process this week, so we haven’t really run many tests, but the render to the 1080p-30 file seems to run about 3x real time. It’s not a great solution for long-form projects. We’re hoping that in future versions of Media Composer (or Quicktime?) will have Quicktime Reference support for 1080p-60 files which would drastically speed up the process.
See examples of the different steps/results:
1080i-59.94 footage and project, exported as a Quicktime Reference:
https://vstream.lakelandcc.edu/Media/Marketing/MP4_Comparison/Project_1080i_Render_QTR.mp41080i-59.94 footage and project, exported as DNxHD 1080p-30:
https://vstream.lakelandcc.edu/Media/Marketing/MP4_Comparison/Project_1080i_Render_DNxHD_30p.mp41080i59.94 footage in a 1080p-60 project, exported as DNxHD 1080p-30:
https://vstream.lakelandcc.edu/Media/Marketing/MP4_Comparison/Project_1080p60_Render_DNxHD_30p.mp4TL/DR Short Version: Was able to export smooth, non-interlaced 1080p footage from 1080i source in Avid Media Composer by working in an 1080p-60 project and exporting DNxHD 1080p-30 file to Sorenson Squeeze 9.
Our hardware for this whole experiment:
Sony PMW-320k camcorders at 1080i-59.94Avid Media Composer v8.3. All source files AMA Linked from the system raid.
I/O with AJA Kona and viewed via HD/SDI on the confidence monitors
Sorenson Squeeze 9 as the conversion between the DNxHD to MP4.
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5 Replies
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I’ve never had an issue outputting a 1080i QTref from a MC mixdown and encoding that to an mp4 1080p using Adobe Media Encoder. Being so long ago since I used Squeeze though I can’t recall an issue using that as well.
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Oops, try this link for the 1080p60 project file:
https://vstream.lakelandcc.edu/Media/Marketing/MP4_Comparison/Project_1080p60_Render_DNxHD_30p.mp4 -
William,
I dusted off my copy of CS 5.5 and ran the Quicktime Reference file through encoder. It certainly did a better job of removing the interlacing, but it kept the shutter effect. I also ran it through Vegas and found similar results.
One other thing I discovered (and again, I could be way late to the party on this) is that none of the software I’ve tried for the rendering knows how to interpret the fielding of the Quicktime Reference file. In Adobe and Vegas you can set the properties of the source file to upper field first. I haven’t discovered a way to do that in Sorenson. But as of yet, I haven’t found anything else that shows it without the shuttering effect.
Here’s the examples with Adobe and Vegas thrown into the mix (with working links):
The best looking example – 1080i59.94 footage in a 1080p-60 project, exported as DNxHD 1080p-30:
https://vstream.lakelandcc.edu/Media/Marketing/MP4_Comparison/Project_1080p60_Render_DNxHD_30p.mp41080i-59.94 footage and project, exported as a Quicktime Reference:
https://vstream.lakelandcc.edu/Media/Marketing/MP4_Comparison/Project_1080i_Render_QTR.mp41080i-59.94 footage and project, exported as DNxHD 1080p-30:
https://vstream.lakelandcc.edu/Media/Marketing/MP4_Comparison/Project_1080i_Render_DNxHD_30p.mp41080i-59.94 Quicktime Reference in Adobe Media Encoder CS5.5:
https://vstream.lakelandcc.edu/Media/Marketing/MP4_Comparison/Project_1080i_Render_QTR_Adobe.mp41080i-59.94 Quicktime Reference in Sony Vegas 13:
https://vstream.lakelandcc.edu/Media/Marketing/MP4_Comparison/Project_1080i_Render_QTR_Vegas.mp4I’m certainly not trying to sell anyone on anything, I just wanted to share what we’ve discovered (or more appropriately, stumbled upon). I’m hoping to share it with Avid today and see if they can make the process shorter (even if the rendering isn’t necessarily shorter) within the software.
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I upgraded to MC 8.4, and it supports Quicktime reference exports in the 1080p-60 project. That saves quite a bit of time from what I was doing yesterday. Essentially it skips all of the time related to the step 4 of the original post.
I also uploaded the files to YouTube to see what (if any) difference exporting from the 1080p project made. I was surprised to find that the “Best” file from the original post shows up in YouTube as 1080p60, while the other files just show up at 1080p. The lower resolutions for each file show up at regular (30) progressive scan videos, and all feature the shuttering I’ve been droning on about.
https://www.youtube.com/watch?v=N7Nghg5vDdA
Sorenson doesn’t offer a 60fps setting in the MP4 settings, but they do have a 1:1 for the framerate, which with the 60p Quicktime leads to the smoother motion I’m seeing. At least it’s good to know where the change is coming from.
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I’m starting to think you should inspect the original source footage regarding the stuttering. The shooter may have unknowingly had the shutter set to 1/30, where it’s going to repeat the first field. Check it out in MC and step through each field (shift + left/right arrow buttons)
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