Reducing file size of a recording

brisguy79 · Post by **brisguy79** » Wed Jul 15, 2009 18:09

Apologies if this has been covered, but I can't find the answer from searching.

I've got a P1 and love it, but would be great if I could save/alter the recorded files that I want to keep long term, but with a smaller file size than the SD quality of about 2.5GB/hr.

I want to be able to keep the files on an ext HDD (already doing this), but for various recordings I really don't need the large file size. I'm happy watching things I've downloaded from the internet that are about 700mb or less per hour, as far as pic and audio quality go, but I'm not sure how to go about doing the conversion for this to take place. Obviously it would reduce my storage needs to about 1/4 of what they are now if I get get some guidance. I'm still wanting to store on ext HDD, and not DVD though... the stuff I have downloaded is .avi and works well on the P1. I don't have my P1 networked though, I just move my ext HDD from computer to BW as needed.

prl · Post by **prl** » Wed Jul 15, 2009 19:03

Re-encode in a form that gives a better picture quality/compression tradeoff than MPEG2, for example MPEG4/H.264.

brisguy79 · Post by **brisguy79** » Wed Jul 15, 2009 19:37

prl wrote:Re-encode in a form that gives a better picture quality/compression tradeoff than MPEG2, for example MPEG4/H.264.

Awesome, thanks for the reply. Any suggestions for freeware that I should use to do this? from the BW files? It looks like it produces a unique file type?

IanSav · Post by **IanSav** » Wed Jul 15, 2009 19:55

Hi Brisguy79,

brisguy79 wrote:Awesome, thanks for the reply. Any suggestions for freeware that I should use to do this? from the BW files? It looks like it produces a unique file type?

The Beyonwiz generates a bog standard MPEG2 Transport Stream formatted file. (The recordings are broken up into 32MB file size chunks to make file management easier. WizFX or the other user contributed utilities can join this segments back into a single .TS file that can be fed into and .TS editing program. There are a number of threads describing tools that can be used for various conversions.)

Regards,
Ian.

brisguy79 · Post by **brisguy79** » Fri Aug 28, 2009 18:22

Rehash of this thread. I haven't been looking at this lately until the past couple of nights.

I'm not happy with the results I'm getting, so am hoping someone has some info that will help. I'm using WizFX and freeware called "Super" to do a conversion. I'm trying to get recordings I want to keep to a smaller file size. I've been happy with the quality of downloaded content (eg. Topgear), which is about 800mb/hr, and even the lower file size is okay. SD from the Beyonwize is about 2.5GB/hr.

My process/settings are:
1. Copy the recording to ext HDD via USB from the BW
2. Copy folder from ext HDD to computer HDD
3. Run folder through WizFX to join the 32mb files to make once big TS file.
4. Use "Super" to convert the TS file to an MP4 file with the following settings:
Video codec: H.264/AVC
Scale size: 640:368
Aspect: 16:9
Frame rate: 25fps
Bitrate: 912kbps

Audio: AAC LC
Samping freq: 44100, channels 2, 96kbps

Its mainly for sport, but the picture is a bit grainy, and smaller faster moving objects are blurry/pixelated a fair bit of the time.

Has anyone got any suggestions for settings, or alternative software? Hopefully someone has done this kind of compression/file downsizing succesfully.

netmask · Post by **netmask** » Fri Aug 28, 2009 18:28

AutoGK, but you will first have to run the TS file through MPEGStreamclip and convert to MPEG2 - that's very quick. With AutoGK you can preselect the file size you want and I would suggest a fixed width of 720

brisguy79 · Post by **brisguy79** » Fri Aug 28, 2009 19:57

netmask wrote:AutoGK, but you will first have to run the TS file through MPEGStreamclip and convert to MPEG2 - that's very quick.

Thanks. I have used AutoGK, but will give it another go with the settings you've suggested. Any reason why I have to use MPEG Streamclip? I can use the TS file directly in AutoGK, or is this not a good idea? I do all my editing of content (trimming adds etc) on the BW before I copy the file to the ext HDD for use at my computer.

grl · Post by **grl** » Fri Aug 28, 2009 20:46

I find editing on the BW too course grained. I either end up chopping off something I wanted or leave some part of an advert I don't want. I top and tail on the BW only and then transfer to PC (via network) and use ProjectX to remove ads and fix any TS file problems. I recombine with mplex and then convert/shrink with autogk.

brisguy79 · Post by **brisguy79** » Fri Aug 28, 2009 20:51

Yes, I agree with the cutting of adds with the BW being a bit hit and miss. will investigate ProjectX based on the recommendation.
What sort of compression and other settings to you use in AutoGK?

is the process and results the same for recordings taken from HD channels as SD channels?

grl · Post by **grl** » Fri Aug 28, 2009 21:18

Same process for SD and HD. The bigger files for HD make everything work harder on the PC - projectX and autogk of course. I tend to record in SD when I have the option and makes the internal disk in the P2 go further. Mostly I watch stuff on an old CRT set so when it gets upgraded that will probably change and more stuff will be recorded in HD.

I vary the parameters in autogk. There aren't that many I fiddle with. I set the file size I want and often set fixed width in advanced to 720. I tend to pick 1400MB for 1.5-2 hour shows and 700 for 1 hour shows. I recently recorded an old McGyver episode that was not wide screen so didn't set 720 fixed width. I also picked 1/2 CD size for it. It looks OK given the quality wasn't that great to start with. It is a personal taste thing, mostly.

netmask · Post by **netmask** » Fri Aug 28, 2009 21:34

brisguy79 wrote:
netmask wrote:AutoGK, but you will first have to run the TS file through MPEGStreamclip and convert to MPEG2 - that's very quick.
Thanks. I have used AutoGK, but will give it another go with the settings you've suggested. Any reason why I have to use MPEG Streamclip? I can use the TS file directly in AutoGK, or is this not a good idea? I do all my editing of content (trimming adds etc) on the BW before I copy the file to the ext HDD for use at my computer.

AutoGk doesn't like the TS file that the BW produces and can have variable results like not having sound etc. Running it through MPEGStreamclip cleans out the subtitles and second audio track if there is one and produces a nice clean MPEG2 file that AutoGK handles smoothly. You could also use ProjectX etc.

tonymy01 · Post by **tonymy01** » Fri Aug 28, 2009 23:03

Yep, projectX toM2P creates an MPEG2 program stream file (but doesn't tidy up stream errors like a full demux will).

grl · Post by **grl** » Sat Aug 29, 2009 07:15

If you want to try projectX look at netmasks signature for a url with how to use it. It takes a bit of effort to set it up.

brisguy79 · Post by **brisguy79** » Wed Oct 21, 2009 20:28

I'm still struggling with achieving what I want to do.
I must admit I haven't had a chance to look into cleaning up TS files as was mentioned in a previous post. So basically AutoGK has been dealing with these. From what I can tell the TS files I have tested with don'thave errors in them though.

I've been trying on and off for the past month to figure out some consistent settings that will work on AutoGK for me to convert my BW .ts files to .avi format.

The FAQ section of the forum refers to being able to get a 1hour recording down to 350mb, which I initially thought would be possible. I've been basing my experiments off torrent avi's for shows such as Top Gear, which are about 700mb/hr, and older versions were still okay at around 400mb/hr.

I currently use the following settings in AutoGK:

Target quality: 24% (comes out at 25 and a bit, but close enough to 800mb/hr). The files I convert are all various lengths due to top/tail and ad removal.
Fixed width: 720px
Audio: auto
Codec: DivX

I've tried at smaller file sizes and the picture goes very blotchy. I'm also basing this from SD recordings, not HD, if that makes a difference.

Should a 720px file still display okay on a larger TV (eg. 50in). I have a 76cm/32in TV, but will eventually get something bigger in a few years, and would like to avoid my AVI's not displaying well.

Hope this is clear enough to understand what I'm trying to do and how I'm going about it. Very much a newbie to digital recording so am on a bit of a steep learning curb!

netmask · Post by **netmask** » Wed Oct 21, 2009 20:59

My set up for AutoGK is fairly standard now.

For 1 hour episodes of well lit shot for TV, like for example NCIS etc I use a fixed width of 720 and a fixed size of 350MB and use Xvid as the codec as you have more options available than DivX. In the secret menu I use the sharp matrix.

For 1.5 hour movies - the same but 700MB as the size.

I do not use the % option as this is a single pass method and IMO doesn't give optimum results as selecting a fixed size and consequently a 2 pass encode.

I think you will find many of the downloads you refer to use this method - some of them use the full Gordian Knot suite but believe me you don't want to go there unless you want to devote your days and nights mulling over options

If you want to squeeze a bit more quality check where the closing titles start and you can lower the quality from that point on - see the secret menu (cnt F9)

Reducing file size of a recording

Reducing file size of a recording

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