I want to use megui or maybe ripbot to re-encode my blu-ray m2ts hard drive backups to 720p, for better playback on my pc & also to reduce the filesize. I plan to play the films on a 720p projector at about 150" diagonal so I don't want any loss of quality (as little compression as possible to match the blu-ray original quality). All I want to do is reduce it down to 720p resolution. I'm not an expert with the Megui settings, so I'm just wondering if the SA Blu-ray profile is designed to compress, or to be identical to the original blu-ray quality. If it is for compression, could someone please edit or create a profile for keeping the original blu-ray quality please? Or is there a different program that just resizes the resolution down to 720p without reducing quality? Thanks.
In order to resize down to 720p you will need to install avisynth and make an avisynth script with a resize function. eg. crop( 0, 130, 0, -132)# crops black bars LanczosResize(1280,544)# resizes A decent encoder can reduce the file size to DVD4 size at 720p without considerable loss in quality.
Thanks for your reply, but I already know how to encode it, I just want a profile that is designed for 720p while keeping original blu-ray quality (preferably no compression or quality loss). The main reason for this is that compressed films look terrible in my opinion when projected at 150", there were blocks & "steps" of differences in the picture, especially in dark scenes, it was like there were black squares & wierd shapes in the darkest scenes instead of different shades/tones. I'm storing them on a 500gb hdd, so although reduced filesize would be good, it's not as important to me as keeping the quality. I guess it should be reduced filesize anyway, being 720p instead of 1080p.
Here is what I used for Casino Royale which is compressed to a DVD9: program --pass 2 --bitrate ~7400 --stats ".stats" --deadzone-inter 17 --deadzone-intra 6 --ref 7 --mixed-refs --no-fast-pskip --bframes 7 --b-adapt 2 --b-pyramid --weightb --direct temporal --deblock -1:-1 --subme 9 --partitions all --8x8dct --me esa --merange 32 --threads 6 --thread-input --cqmfile "C:\Users\Downloads\Prestige Matrix\prestige.cqm" --progress --no-psnr --no-ssim --output "output" "input" --sar 1:1 Of course x264 profile is not everything and is different for every movie, you also have to configure avisynth, but that's for you to figure out.
Here is an explanation in ordet to help properly define the technical components... Blu-Ray uses AVC (and VC-1) for video which stands for Advanced Video Compression. It is H.264 (MPEG4 part 10) lossy video compression, just like MPEG2 is. It also supports many different types of audio streams, both compressed (AAC, AC3 Dolby Digital 5.1) as well as uncompresed (PCM / LPCM). The idea to down-scale from 1080p to 720p is quite typical when considering 80% (i'm guessing) of people with an HD display are still at a native resolution of 720p, so the higher storage of a 1080p M2TS file is wasted considering your immediate needs. The concept behind Blu-Ray is that with a disc of a high storage capacity, the video (MPEG4 part 10) and audio can be stored at a very high bitrate, thus giving you a near original uncompressed experience. But it is still a compressed video image. Bottom line is that the 1080p video is already compressed. When you down-res, you will most likely use a lower bit rate on the destination for encoding so will not notice the loss. An easy way to see this in action on your original Bu-Ray disk is on a PS3. Hit the 'Display' button on the remote and you will see in the title bar the format and bit rate of video and audio as it is playing. This is also true for DVD playback (MPEG2). The reason for moving from MPEG2 to MPEG 4 part 10 is that the compression is better with the later, thus a lower bitrate can store more. This next part you may already know. When it comes to audio, unless you have an HDMI link to your amplifier I highly reccommend always choosing the AC3 Dolby Digital 5.1 audio source as a direct pass-through/untouched. Re-encoding to AAC will not work on a TOSLINK optical connection as a blu-ray (PS3) player will convert to PCM which uses more bandwidth than the TOSLINK can handle and sounds really bad. Also, and just to add a bit of additional context, you may remember H.263 which is MPEG4 part 2. The popular DivX and XviD encoders used this, but it never made it big in terms of commercial impact. THe reason sthat everyone jumped on converting MPEG2 to MPEG4 part 2 (DivX) are the same as they are today, but just with a different set of variables. I hope this helps.
