Honey, I can't shrink this FLV!

August 4, 2009 10:36 AM

Looking for advice on flash video compression. I can't seem to produce the small, high quality files that others are.

I'm using Sorenson Squeeze 5 to compress/encode my flash videos. I use their VP6 codec.

Here's where my frustration begins. Most of the videos that I've encoded end up being around 8 MB/minute and compared to other flash videos samples I've seen (that are usually around 2/3 the filesize) they look like crap.

I wouldn't mind it if my files were just a little bit larger - but the fact that mine are larger and STILL look worse just boggles my mind.

Certainly I must be missing something. This is my workflow:

Edit in Final Cut Pro. Export self contained MOV in highest quality (typically Apple's native HD codec). Import that into Sorenson Squeeze and compress/encode to FLV.

Don't hesitate to ask if you need more details. I appreciate any assistance you can provide.

Thanks!

posted by siclik to Media & Arts (16 answers total)

Are you using the On2 VP6 plugin? That's the one that the Flash Video Encoder (that comes with Flash) uses by default, and it seems to produce the tightest results in my experience.
posted by le morte de bea arthur at 10:55 AM on August 4, 2009

The type of encoder doesn't really matter, but what matters is the settings you use to encode.

How many frames do you want to show per second? Somewhat statical video images, like interviews, can be shown at 14/15 frames per second, whereas sports will always need the 30 f/s.

This is a rule of thumb for me, and often it cannot be said what settings will do before a test video is made.

The same goes for the amount of bits you give to the video per second.

Also, the sound quality can often be a lot less than in your source file, meaning less bits again, before serious a quality loss will be heard.
posted by ijsbrand at 10:57 AM on August 4, 2009

Response by poster: Yes, I'm using the On2 VP6 Plugin. My videos are widescreen format.

I'm trying the Adobe Media Encoder as well, but I've read that Sorenson Squeeze usually produces higher quality files.

My videos usually have motion throughout, so cutting the frame rate would be noticeable past 24 fps. I will take a look at the audio, but as I recall, I reduced that down to less than 100kbps already.

For a widescreen video (480x270), what bitrate would you suggest? At this point, anything close to the sample I provided above would be fantastic.
posted by siclik at 11:03 AM on August 4, 2009

The quality of the source makes a lot of difference for any diluted end product.

End I think it is hard to surpass the image quality of what the film studios produce; in lighting alone.

When I make FLVs, I typically use home recorded clips from TV programs, so the source is already not that good, and I can end up with something that doesn't need more than 1 MB for a a minute of video and audio.

The examples you gave, are in another league.
posted by ijsbrand at 11:51 AM on August 4, 2009

Response by poster: I understand what you're saying about the source quality, but I thought most of what I filmed was well lit. In addition, it was in HD. I could understand if there were a few more artifacts in a few scenes, but in my opinion, the videos in the sample I provided can't even be compared to what I did (and my files are larger!).

Is there some encoding program that I'm unaware of that can achieve that sort of quality?

Here's a video that I encoded. It averages about 7.8 MB/sec.

The other examples above average around 5-6 MB/sec.
posted by siclik at 12:49 PM on August 4, 2009

My experience has been that the On2 VP6 encoder is superior to Sorenson Spark, so I'd recommend you continue to use that.

Ensuring that both the width and height of your encoded movie are evenly divisible by 16 will improve quality and playback. 512 x 288, for example.

In the samples you reference, the dimensions of your movie are quite a bit bigger than those of the videos with higher quality and smaller file size. Yours appears to be about 180% bigger, in fact (in terms of number of pixels). That extra size is going to make a lot of difference in your final file size. For a more accurate comparison, output your video to a size similar to those other samples, and see if quality/file size is more what you are hoping for.
posted by thinman at 1:58 PM on August 4, 2009

7.8MB/s? I think your figures are a little off. The Funny People clip on the page you linked is 640x360 at 23.976 fps and 800 kbit/s video bitrate, for an overall Q_f of 0.145. Your clip is 480x270 at 29 fps and 917 kbit/s video, for an overall Q_f of 0.244. So your video bitrate is only 117 kbit/s higher, which is about 15%. In addition, the Funny People clip has mp3 audio at 48 kbit/sec whereas you have 128 kbit/sec audio, so that's another 80 kbit/s difference.
posted by Rhomboid at 2:02 PM on August 4, 2009

You should show us the lossless file straight from final cut, so we can see what the source is really like before compressing.

Even though you're shooting with an HD camcorder, you're never going to compare with a hundred thousand dollar movie camera.
posted by derbs at 2:17 PM on August 4, 2009

Response by poster: Ok, I'm having trouble figuring out how my video is 180% bigger (dimension-wise).

Using the Funny People video as a reference, I think my video's dimensions are actually smaller.

I made a big mistake in noting the differences in filesizes/bitrates. I meant to say 7.8 MB/min. (my video) and 5-6 MB/min. (other videos).

I got the 7.8 figure by taking the total size of my video (89 MB) and divided it by the number of minutes long the video is (11.4).

The Funny People video is 23.8 MB and 3.5 minutes long, which means every minute of that video you download is only 6.7 MB.

This could very well be because of my audio - we'll see. To determine this, I'm compressing a new flash video that exactly fits the "Funny People" specs. I'll upload a one minute sample in about 10 minutes.

Thanks for all your input so far everyone.
posted by siclik at 2:24 PM on August 4, 2009

Response by poster: Hmm . . webserver is down at the moment. Thought The Planet would be able to handle this traffic.

If you're trying to evaluate my video, please be patient as I'm having them reboot the server.

I'll upload a new sample as soon as the server is back online.
posted by siclik at 2:51 PM on August 4, 2009

Sorry if I've missed this in thread, but is there a reason that you need to compress to FLV? H.264 offers much better quality and has been supported since Flash Player 9, I believe. That would certainly be worth experimenting with IMO.
posted by Magnakai at 4:01 PM on August 4, 2009

Ok, I'm having trouble figuring out how my video is 180% bigger (dimension-wise).

Using the Funny People video as a reference, I think my video's dimensions are actually smaller.

You are correct. I was basing my numbers on the assumption that the videos were embedded at 100% of their actual dimensions. I see now that Funny People is actually 640 x 360, and not 425 x 344. Although I can't access your FLV at the moment, I'm guessing from other comments that it is smaller than the 672 x 398 you embedded it at.

Sorry about that.
posted by thinman at 4:46 PM on August 4, 2009

Response by poster: Well, server's still down. I did compress a one minute sample to match the dimensions/bitrate/etc. of the Funny People clip and, although the filesize was smaller, the quality still was not anywhere close. I understand that, yes, they may have some better lit scenes. But there were plenty of dimly lit scenes (comedy clubs) that still looked better than any one of the frames in my video.

Regarding H264, I am aware that it is a good alternative. Flash Player 9 nearly has the penetration rate of 8 (and previous versions), however, it's still not high enough for me to rely on it solely. I know we're talking the difference between 0.01% penetration rate, but, from my experience, a majority of our target market falls within that margin (think farmers and late adopters of technology). That is the main reason I'm spending so much time worrying about this filesize and quality issue - a lot of our target market is STILL on dialup and I have to plan accordingly.

I'm mainly concerned with the fact that I just can't get anywhere near the quality of those other videos when I copy their settings line-by-line.

Is there something else I'm missing?

Although our server is still down (due to power issues at The Planet), I've uploaded a higher quality "source file" to my dropbox. Although it's been compressed again out of Final Cut Pro, perhaps it will give you some idea of the source I'm dealing with. It's half the resolution of the source file I'm importing into Sorenson, if that helps.

Since I can't upload this to our web server, I'll upload it to my dropbox:

Here is a one minute FLV sample that I've re-compressed to match the Funny People settings mentioned several times above (you'll need a FLV player to watch it). You be the judge - is it anywhere close? Is there anything else I can do to keep filesize down yet improve quality?
posted by siclik at 4:56 PM on August 4, 2009

I've used Vimeo's compression guide as a starting point with great results.

I've got a video that is 11 minutes long, compressed to 40MB. The source was a 3GB 1920x1080 quicktime movie shot with a Canon 5D MII. Using the Vimeo guide above and quicktime pro (which you should have since you have Final Cut Pro) I exported the movie to MP4 at 480x270 using h264 encoding at a data rate of 1350kb/s and frame rate of 30fps. The MP4 file was about 69MB. I then took that file and dropped it into Flash Video encoder and set it to encode video (but not audio since it wasn't needed) at the same data rate of 1350kb/s. The resulting file is what you see here.
posted by inviolable at 4:56 PM on August 4, 2009

Mayor Curley dropped some science on video compression on a previous question.

With Flash 9, you could use MPEG-4 or H.264, & those have better quality per bitrate than VP6, so it's worth getting an upgrade, even on dialup.
posted by Pronoiac at 6:26 PM on August 4, 2009

Why aren't you using h.264? Flash now wraps around that and it's trés better as a codec?
posted by filmgeek at 4:07 AM on August 6, 2009