Re: [vdr] Compressing VDR recordings without losing quality.
Like I said, you aren't going to get smaller files without making a sacrifice. If less filsize is most important to you then you should focus on a target bitrate at the expensive of quality. One option is to requantize original MPEG2 stream. http://code.flexion.org/M2VRequantiser.html It makes your file smaller with minimal quality loss on video 'focus' area. But it is fairly fast and easy to use via pipes. Demux - requant - Remux. ___ vdr mailing list vdr@linuxtv.org http://www.linuxtv.org/cgi-bin/mailman/listinfo/vdr
Re: [vdr] Compressing VDR recordings without losing quality.
On 29.10.2010 00:47, Carsten Koch wrote: Hi, I have been using VDR for over 10 years now, so I currently have ~4TB of VDR recordings. Some of them are SDTV/MPEG2, many of the newer recordings are HDTV/H.264. ... my first suggestion is to upgrade storage if you compare the time you will have to invest and the power consumption of the system that recodes all the stuff then new 2TB disks look much more effective you also will have lots of problems with async sound, lost audio streams (ac3) and picture or just with broken recordings, what will consume additional time you can read about a conversion script here: http://www.vdr-portal.de/board/thread.php?threadid=82167 ___ vdr mailing list vdr@linuxtv.org http://www.linuxtv.org/cgi-bin/mailman/listinfo/vdr
Re: [vdr] Compressing VDR recordings without losing quality.
On 29/10/10 00:28, VDR User wrote: I wonder if there is an easy way to recompress all recordings that are not already H.264 into H.264 files, making them a lot smaller without losing any quality. The only way to not lose quality is to keep the bitrate high, especially for recordings with a lot of motion. You should encode with constant quality (CRF) set to whatever the minimum quality you want to preserve. You can also reduce the resolution a bit, just make sure to maintain the aspect ratio. And don't try to scale interlaced material without using a good deinterlacing filter first. Bottom line is that you will not get smaller filesizes without making sacrifices. Data is lost with every encoding pass. The point of H264 is that it can achieve better quality for a better bit rate. Although some quality will be lost by transcoding, you could probably halve the file size without making a noticeable difference. ___ vdr mailing list vdr@linuxtv.org http://www.linuxtv.org/cgi-bin/mailman/listinfo/vdr
Re: [vdr] Compressing VDR recordings without losing quality.
On Fri, Oct 29, 2010 at 10:59 AM, Tony Houghton h...@realh.co.uk wrote: The only way to not lose quality is to keep the bitrate high, especially for recordings with a lot of motion. You should encode with constant quality (CRF) set to whatever the minimum quality you want to preserve. You can also reduce the resolution a bit, just make sure to maintain the aspect ratio. And don't try to scale interlaced material without using a good deinterlacing filter first. That's a great point, I should have mentioned it but since I didn't, it's good you did. Bottom line is that you will not get smaller filesizes without making sacrifices. Data is lost with every encoding pass. The point of H264 is that it can achieve better quality for a better bit rate. Although some quality will be lost by transcoding, you could probably halve the file size without making a noticeable difference. That sounds good when you read the datasheets but real world results are a bit different. Also, what you're referring to is encoding comparisons all from a raw source - not mpeg2 vs. the same mpeg2 reencoded in h264. I can't stress enough that there is no magic to be had here for the reasons in my previous post. ___ vdr mailing list vdr@linuxtv.org http://www.linuxtv.org/cgi-bin/mailman/listinfo/vdr
