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Author Topic: Advice required - ISO files.  (Read 626 times)

AlexS

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Advice required - ISO files.
« on: January 16, 2021, 01:37:58 pm »

I have lots of ripped ISO files on my hard drive. DVD's and BluRays. I'm running out of space.

My question is, can I compress them keeping the same quality (I don't want lossy compression) and still immediately play them on my Chromecast Google TV box (or whatever). I want to keep the menus etc. What file format is recommended and what utils should I use to do this?

thx.
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wer

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Re: Advice required - ISO files.
« Reply #1 on: January 16, 2021, 01:53:55 pm »

Prepare yourself for disappointment.   :)  Your media files are already encoded with a lossy compression algorithm.  If you re-encode them to make them even smaller, you will lose quality.  That said, whether the loss of quality is perceptible to you is a matter for your assessment.

There are packages out there that do the rest of what you want, with lossy compression. Google DVDshrink and DVDfab.

If you want to absolutely preserve the original quality of your rips, add hard drive space.

Storage is cheap.
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AlexS

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Re: Advice required - ISO files.
« Reply #2 on: January 16, 2021, 02:22:04 pm »

Thanks..
But I'm closing with DVD fab to ISO - it's a 1:1 copy, so no lossy compression.
Can you recommend any file formats alternatives that are better than ISO ?
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wer

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Re: Advice required - ISO files.
« Reply #3 on: January 16, 2021, 02:49:11 pm »

it's a 1:1 copy, so no lossy compression.

You seem to misunderstand. Your DVDs and BluRays are using lossy compression ON THE DISC. You cannot avoid it. They were already using lossy compression when you ripped them. (There are no movies available by disc or download that are not using lossy compression)  You've copied that data to your hard drive intact, so no further loss at this point. But any further attempt at additional compression will cause an additional loss in quality.

With any file format you choose, you will either get the same quality at the same size, or reduced quality at a reduced size. There are no other options. If you need further ability to expand your collection, you must either recompress and lose quality, or buy more storage.

Your original question was about further reducing file size without using lossy compression or loss of quality. That is not possible.

ISO/IFO are generally the best formats if you insist on preserving the menus.  If you decide you don't need the menus and just want the content, MKV is best.  Converting to MKV doesn't cause any loss in quality: all the quality you have now is perfectly preserved, but converting to MKV does not make it any smaller.

You did everything optimally at the beginning, with your goals of preserving quality and menus.

I prefer MKV myself, but I don't want the menus.

I hope this helps...
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Awesome Donkey

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Re: Advice required - ISO files.
« Reply #4 on: January 16, 2021, 02:53:10 pm »

If you want to absolutely preserve the original quality of your rips, add hard drive space.

Storage is cheap.

Pretty much this is the best advice.
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AlexS

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Re: Advice required - ISO files.
« Reply #5 on: January 16, 2021, 02:56:33 pm »

You seem to misunderstand. Your DVDs and BluRays are using lossy compression ON THE DISC. You cannot avoid it.

Oh I completely understand that, that's no shock to me whatsoever. Obviously I don't want the original supplied stuff compressed further. Thanks for you advice on the file formats :)

Adding hard drive Space will be a hassle for me, I have a synology server that is fully occupied by hard drives, hence I'm trying to reduce rather than expand. Thx
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dennismf

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Re: Advice required - ISO files.
« Reply #6 on: January 18, 2021, 02:34:09 am »

I have converted high bit rate video files (20mbps to 40mbps) to mkv (matroska) format with HEVC encoding. I have used both Handbrake and TmpGenc. I usually use a target bitrate between 10 and 15mpps (depending on the apparent "sharpness" of the source material).

I personally cannot perceive any visible degradation, although there must be some loss of detail.

Once the video is compressed, often the DTSHD audio track is as large as the video component!

I have experimented with converting the DTS audio track to FLAC. The matroska (mkv) file container can handle HEVC (H.265) video with either a DTS or FLAC audio (as well as many others).

Occasionally I find that the FLAC audio stream is significantly smaller than the DTS. On other occasions they are of similar size.

On a small number of files I found I had audio sync issues using the FLAC audio. When this happened, I just retained the DTS. Also, many devices seem unable to play DTS audio, so a conversion to FLAC can help here.

Keep in mind that the HEVC video decoder requires a fairly powerful computer. Older computers and particularly older phones and tablets can struggle with HEVC.

I had the tools to do this as I produce small videos using HEVC and so I have the tools required.

As a starting point:

Handbrake (free) for video encoding as HEVC
MediaCenter for the DTS to FLAC conversion
MKVToolNix (free) for matroska packaging and for extraction of video and audio from .m2ts

I am not making any recommendations, just reporting my experience. :)

Dennis MF
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zybex

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Re: Advice required - ISO files.
« Reply #7 on: January 18, 2021, 02:56:39 am »

Adding hard drive Space will be a hassle for me, I have a synology server that is fully occupied by hard drives, hence I'm trying to reduce rather than expand. Thx
You're just postponing the problem :)

Quote from: dennismf
Handbrake (free) for video encoding as HEVC
MediaCenter for the DTS to FLAC conversion
MKVToolNix (free) for matroska packaging and for extraction of video and audio from .m2ts

I think you can do all of it with just Handbrake. It accepts .m2ts as input, and if you chose MKV as the output format you can also set the audio conversion to FLAC 16/24bit.
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