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Author Topic: Compression HELP  (Read 2966 times)

Offline Peter17

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Compression HELP
« on: July 30, 2013, 11:02:49 AM »
HI everyone,

Could anyone tell me which program is the best for windows PC to compress videos? I have the Canon Eos Rebel T3i, started my photography 6 months back and have been shooting in Manual Mode RAW. However I want to try video recording but I find the files are too huge. Anytime I try to compress the video or convert to another format the video turns to garbage. I understand the in camera compression has already stripped away as much as it can to fit the quality but the files are too huge to even upload online. I tried the max settings and the low settings on the camera. 2 minutes is over 1GB worth of data.

Offline dougdirt

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Re: Compression HELP
« Reply #1 on: July 30, 2013, 11:19:14 AM »
You are going to get plenty of big files if you want to produce HD videos.

My first suggestion would be, if you aren't already doing so, compress it to 720p. Very few people can tell the difference between 720p and 1080p on the screens they have available to them.

My next question would be, what program are you using currently to compress your videos?

Offline AndyCivil

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Re: Compression HELP
« Reply #2 on: July 30, 2013, 11:31:11 AM »
I think they chose the data rate for video to be 'just less' than Class 6, to make a wide range of available memory cards compatible (they didn't figure with the huge number of fake Sandisk cards there would be with poor write speeds). I would say that the data rate is "plenty" rather than optimum, and you can compress somewhat, without visible loss of quality. I make this observation, since it seems that all video modes appear to create videos with the same data rate (at least on my T2i)!

It does of course depend on your material. I've been impressed with the data rates of online streaming news shows and stuff, but when you look at it, they're 'talking head' things with little movement. One of the reasons you may be able to compress your T3i stuff is that the camera doesn't seem to reduce the data rate when it should be possible to do so. If you have 'talking head' material or similar, your scope for compression should be promising.

What tool you use to compress your videos depends a bit on what kind of hacker you are. I use FFmpeg because I'm a fan of open-source software, and I like to write scripts/batch files because it makes up for my poor memory... LOL But it's not for the faint of heart, because it's also hard to work out how to do things without GUI menus to offer you choices.

I have to say, though, it's hard to accept a compressed video where you've squeezed it to the point where quality loss is just discernable, when you have the original available ;-)

If you want to share a clip using dropbox or something, I can run FFmpeg on it to see if it impresses you or not...

Offline DaveDad

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Re: Compression HELP
« Reply #3 on: September 20, 2014, 01:46:06 PM »
Hi AndyCivil,

I have had a T2i camera for 3 years now. I have tried several programs to batch process convert the video to a file that I can work with in Sony Vegas Movie Studio HD Platinum 10. The reason being is that I can't edit more than like a gig of the H.264 video in there before Vegas crashes. I have spent countless hours trying to find the best compression settings that are not pixelated and haven't found what I need.  My end result is to burn the video onto DVD or Blu-Ray.  I just bought a Blu-Ray burner, but I haven't dished out the cash for the Sony BluRay Architect software ($40)http://www.sonycreativesoftware.com/dvdastudio yet to start learning how to make a BluRay disc.

I just signed up for this t2iforum, so I don't know if this is the best avenue to ask my questions.

The questions that I have always had were:

1) Should I invest in getting a graphics card that can enable me to edit the H.264 in Vegas in real-time? Is there a card out there that can do that? My costco HP computer's DVI output failed on me recently and I have been using the VGA output!

2) Should I buy the Sony architect software so that I can start burning BluRay discs associated with my Sony Vegas?
   2b) Do you know of a freeware bluray software that I could use?  I'm not sure, but I think Vegas won't allow me to save my edited videos as a bluray version unless I have their architect software.

3) If I need to go down the route of using Vegas without a graphics card upgrade, what program do you suggest that I use to convert the H.264 to something else? I saw your post in which you recommended FFMpeg. Is that the best free converter out there? I just downloaded WinFF...do you like that program?

4) I have been shooting in 1080 30 fps with the T2i.  My hard drive is filling up and I'm afraid that it may crap out on me one day. I am not desiring perfection in the conversion, but what are the best conversion settings, codec to use for me to edit in a NLE system?

5) I have started to archive my photos and videos onto bluray single discs, but it is a painfully slow process. Do you think I should convert my RAW and .jpg images to lower resolution and convert my videos before archiving?

My system: HP p7-1298cb  that I bought at Costco 2 years ago.
Processor:    AMD A10-5700 APU with Radeon HD Graphics 3.40 Ghz
Installed memory: 12 GB
64-bit OS - Windows 7 Home Premium  Service Pack 1

The bottom line is:  I am stuck with my purchase of the t2i... I take lots of videos & photos of my kids and our adventures.  I want to be able to find a streamline process of archiving my media and then be able to streamline the process of making movies so that we can watch them!  The t2i has been a pain in some ways because I have limited time with my real job and family!
Thanks for your time looking at this.  If you think I should start a new topic and include this in there, let me know.


Offline DaveDad

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Re: Compression HELP
« Reply #4 on: September 20, 2014, 02:25:11 PM »
Hey Andy,

so I tried WinFF and I am actually surprised by the results.

The t2i video I shot was 1920 x 1088  29 fps  ( I assume windows  7 rounds the 29.97 ? )
with a data rate of 45991 kbps,  total bitrate of 47536 kbps
  Audio bit rate was 1545 kbps
  Channels  2
   Audio sample rate 48 kHz
  It was 238 megs big!

The WinFF settings were:
Convert to:  MPEG-4
Preset:  MPEG-4 1080p
  Video settings:
       8000   bitrate
      29.97  Frame rate  (does it matter if its 29.97 or 29 fps?)
      1920 x 1088  video size
      16:9  aspect ratio (I assumed this was the correct input)
   I clicked on the 2 pass.

 Audio settings:
    120   audio bitrate
   48000   sample rate
   2  audio channels
    256  volume
    I left the "Sync" box blank.

Then clicked on Convert.   It took a while...maybe 5 minutes?   for 41 seconds of video.

The video looked very similar to the original. I haven't seen that happen in a long time. I am really excited especially since I have a lot of videos that I want to convert!

Do you have any suggestions on how to improve the settings? Looks like this is an easier way to use FFmpeg.

Offline AndyCivil

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Re: Compression HELP
« Reply #5 on: September 20, 2014, 06:33:08 PM »
Very interesting post, Dave; I'm working on an answer, I need to try out WinFF just to see if a certain feature is available (I want to try the program anyway because it looks like a good way to get less 'techie' people to use FFmpeg). Please check back tomorrow!

Offline AndyCivil

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Re: Compression HELP
« Reply #6 on: September 21, 2014, 05:54:47 PM »
I tried out WinFF and it seems very good.

Frame size. I think the encoding is done in 16x16 blocks, so the container pixel size has to be a multiple of 16. Now, 1920 is indeed 120 blocks wide, so that's fine, but the vertical resolution is 1080 which is not. For that reason, sometimes you'll see the vertical resolution quoted as 1088 because that's the size of the container, but nevertheless the actual picture is still 1080. I think the .mov file out of the camera reports itself as being 1088 for this reason. Just so you know!

The frame rate is 30 fps. Sometimes, you'll see it quoted as 29.97 because of the broadcast NTSC standard which drops 1 frame every 1000 frames. You're right that Windows 7 truncates the 29.97 to 29 which is WRONG. If you need to use an integer, use 30. If you try to change it to 29 then there will be a frame skip every second. I seriously suggest not putting anything in the frame rate box in the program; then it will just take the frame rate of the input, which is what you want.

Bit rate. There's an option to set a bit rate, for those applications where it matters. And the 'two pass' option will allow it to optimise the process to squeeze the best quality into whatever constraint you have. However you, Dave, are just trying to save 'some' space, without any particular constraint, and so it's much better for you to set a quality level, and let the encoder use whatever rate it needs to achieve that quality. I was going to suggest a value for the "crf" option, but it seems that if you set nothing, it defaults to -crf 18 in any case, which is great quality. I therefore suggest putting nothing in the 'bit rate' box for video. You might like to check in the FFmpeg command, that the "-crf 18" is there, it certainly was for me. You can read up about the crf option here: http://slhck.info/articles/crf And if you want better quality you can go for 17 or for a smaller file, go for 19, but in this case you'll have to edit the option in the "FFmpeg" tab.

Note that if you ask for a certain quality, you'll get smaller sizes on videos that contain little movement, and perhaps higher if you pan across vegetation! But I think the quality level matters to you more than a specific file size. Also, if you're not trying to optimise an exact bit rate, you don't need the two pass option! It won't exactly halve the encode time, because it knows to cut corners on the first pass, but it will save some time. The two pass option does nothing for you!

Hope this helps.