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| Does transcoding also compress? Does burndvd transcode? http://forum.linhes.org/viewtopic.php?f=17&t=12080 |
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| Author: | borgednow [ Mon Oct 09, 2006 8:57 pm ] |
| Post subject: | Does transcoding also compress? Does burndvd transcode? |
I've started preparing to burn dvds of some shows, just to make room. In preparation, I've gone in and corrected some cut points of these shows, and then I selected Transcode off the menu, as it says here: http://www.knoppmythwiki.org/index.php? ... oEditHowTo I noticed that after clipping commercials out of a half hour show, a 1.1 gig recording is shrunk to about 600 meg. I KNOW I didn't clip that much out of these shows. Obviously it's running it into mpeg-4 compression, but am I losing quality? Is there a way to cut commercials without compressing it? I did have some problems with getting transcoding to work. I was getting errors, and found I had the same problem as dwallace did, so I replicated his changes and transcoding works for me now. (here's the link to his thread.) "R5C7 Transcoding not working - HOW I FIXED IT" http://mysettopbox.tv/phpBB2/viewtopic. ... dec++94210 I'm wondering if I MPEG-4 is too low of a resoluton. I'd like to keep as near as possible video quality as I can on these things. My last questions is if I even need to run transcode or not. If I run the Burn DVD function to create an iso, will it also run transcode? If I've already run transcode and clipped the commercials, obviously I don't need to check the Use Cutlist box. |
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| Author: | tjc [ Mon Oct 09, 2006 9:28 pm ] |
| Post subject: | Re: Does transcoding also compress? Does burndvd transcode? |
[quote="borgednow"]Obviously it's running it into mpeg-4 compression, but am I losing quality? Is there a way to cut commercials without compressing it?[/quote] Yes and yes. On the first search for "generational loss", basically every time to reencode something in a lossy format you lose more quality, and it's a cummulative process. On the second, search for MPEG2->MPEG2 lossless transcoding. Here is one thread - [url]http://mysettopbox.tv/phpBB2/viewtopic.php?t=8719&highlight=lossless+mpeg2+transcode[/url] [quote="borgednow"]My last questions is if I even need to run transcode or not. If I run the Burn DVD function to create an iso, will it also run transcode?[/quote] No you don't. As a matter of fact if you're making MPEG2 recordings that you're going to burn to DVD anyway I'd avoid it entirely. |
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| Author: | borgednow [ Mon Oct 09, 2006 9:39 pm ] |
| Post subject: | Re: Does transcoding also compress? Does burndvd transcode? |
[quote="tjc"][quote="borgednow"]Obviously it's running it into mpeg-4 compression, but am I losing quality? Is there a way to cut commercials without compressing it?[/quote] Yes and yes. On the first search for "generational loss", basically every time to reencode something in a lossy format you lose more quality, and it's a cummulative process. On the second, search for MPEG2->MPEG2 lossless transcoding. Here is one thread - [url]http://mysettopbox.tv/phpBB2/viewtopic.php?t=8719&highlight=lossless+mpeg2+transcode[/url] Sweet, thanks. [quote="borgednow"]My last questions is if I even need to run transcode or not. If I run the Burn DVD function to create an iso, will it also run transcode?[/quote] No you don't. As a matter of fact if you're making MPEG2 recordings that you're going to burn to DVD anyway I'd avoid it entirely.[/quote] Thanks. I thought I had to run transcode because the instructions seemed to state it was required, but after thinking about it, it must mean only if I'm keeping it on the mythtv system. That will work for me. The shows I am burning to dvd that I want to keep highest quality will not be transcoded, but cutlisted. The ones I'm not as concerned about for quality I'll still transcode though. |
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| Author: | tjc [ Mon Oct 09, 2006 9:51 pm ] |
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Use the lossless as a first choice. It'll usually knock stuff down by about 20-35% without a loss of quality. Since I record a couple minutes over before and after on most stuff, a HQ recording half hour show goes from 34 minutes and 1.6Gb to 22 minutes and 1Gb, which is at the high end of that range. |
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| Author: | borgednow [ Tue Oct 10, 2006 2:05 pm ] |
| Post subject: | |
[quote="tjc"]Use the lossless as a first choice. It'll usually knock stuff down by about 20-35% without a loss of quality. Since I record a couple minutes over before and after on most stuff, a HQ recording half hour show goes from 34 minutes and 1.6Gb to 22 minutes and 1Gb, which is at the high end of that range.[/quote] Good idea. I've been noticing my recordings have sometimes been cutting off too soon. I haven't been extending my recordings because I only have 1 tuner as yet, but I don't record two consecutive shows that often. It's much worse when the broadcast is delayed and I lose the last 15 minutes or so. At least it's not as bad as in England. I understand show scheduling there is just a half-hearted target. But since most stuff I will keep I want to be as high a quality as I can get, the lossless is going to be my choice. |
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