Now you have found several sources to use for your project, but don't know which one could be the best to use... you must learn how to rate these; experience will help a lot, but if you have not much, here you could find some hints...
Audio/video sources
UHD-BD: the best source up to date: video resolution up to 3840x2160, bitrate up to 128mbps, 10bit color depth, HDR; audio tracks are usually lossless compressed, 7.1 channels - Dolby Atmos, DTS:X, plus all the others available on normal BDs.
BD: still one of the best source; video resolution is up to 1920x1080, bitrate up to 40Mbps; audio tracks could be uncompressed - PCM - or better compressed with a lossless codec to spare a lot of space without losing quality - Dolby Atmos, DTS:X, DTS-HD MA, Dolby TrueHD - or lossy encoded - Dolby Digital, Dolby Digital Plus, Dolby Digital EX up to 640kbps, DTS, DTS-HR, DTS-96, DTS-ES up to 1536kbps - all of them up to 8 channels.
HD-DVD: even if today is a dead format, and almost all titles are available on BD, sometimes there are few titles better than their BD counterparts; video quality is very high, with bitrate up to 30Mbps; audio is similar to BD, with DTS-HD MA at a lower max bitrate, but Dolby Digital Plus at almost double in comparison to BD.
D-Theater: another dead format, this time on tape; few titles released, almost all (if not everyone) on BD, but sometimes there are some little jems to discover; good video quality, bitrate around 20/22Mbps but only MPEG2; audio could be AC-3 or DTS 1.5Mbps.
HDTV: a lot of titles still not present on BD or other HD discs, and many times if they are available, the TV version is different or has different grading or cropping; quality could be really high - ATSC is 1080i MPEG2 at 19.2Mbps, while audio has usually lower quality than other HD sources.
DVD: the most successful digital disc format, present everywhere; very often the same title has different features depending on editions and/or country; quality is good, but not HD; video could be up to 720x480 for NTSC and 720x576 for PAL, anamorphic or not; audio is almost everytime Dolby Digital, but sometimes DTS, usually at half rate, 768Kbps.
VCD: widespread in Asia but not so common in the western countries; some titles could still be available only on this format; video quality is low, MPEG1 352x240 for NTSC and 352x288 for PAL at 1.15mbps fixed bitrate; audio is MPEG stereo 224Kbps at 44.1KHz.
SVCD: rarer than VCD, its predecessor, but with higher quality: video is MPEG2 480x480 for NTSC, 480x576 for PAL, up to 2.6Mbps, audio is usually stereo, but could be up to 6 channels, MPEG up to 384Kbps
Digital streaming: quality varies, from bad SD to very good HD - that could be 720p or 1080p - to great UHD; video bitrates are quite low in comparison to BD and HDTV, but often high enough to obtain good quality; audio could be multichannel, but again usually not on par with BD.
LD: very important format in the past, and with so many titles is quite easy to find out some title never released on DVD or BD; when captured using good players and capture device, quality could be quite good; video resolution could be up to 564x480 for NTSC and 564x576 for PAL; audio could be stereo, analog or PCM 1.44Kbps, or multichannel AC-3 384Kbps or DTS 1.44Kbps.
VHS: once the king of home video, discontinued since few years; sometimes it could be the only way to obtain some particular title; video captured with good VHS, or better S-VHS player or recorder, could be up to 352x480 for NTSC and 352x576 for PAL; audio mono is the norm, but many movies has a stereo Hi-Fi audio track of good quality.
CED, VHD: super-niche formats, video quality is somehow better than VHS but worse than LD; audio could be comparable with VHS Hi-Fi stereo.
Of course, a SD source could be hardly better than an HD one, but how to choose between sources with similar quality? There are some things to take in account: eventual problems like noise reduction, edge enhancement, grain (or the loss of), color grading... if every aspect is similar between the two, bitrate could be a good quality indicator; at the end, you could always use the following formula to know if the bitrate of your source is good enough...
A good digital video should have a bitrate equal or better than
width x height x FPS x motion rank x constant = final bitrate in bps
where the constant should be equal or higher* than
and the motion rank is equal to
Source 1 is 1920x1080, 23.976fps, motion rank 2, encoded in AVC; to have a good quality the bitrate should be:
1920 x 1080 x 23.976 x 2 x 0.07 = 6960328bps = ~6.9Mbps
Source 2 is 1920x1080, 29.96fps, motion rank 2, encoded in MPEG2; to have a good quality the bitrate should be:
1920 x 1080 x 29.96 x 2 x 0.116 =14413012bps = ~14.4Mbps
we discover that source 1 has an average bitrate of 7.4Mbps, while source 2 has a constant bitrate of 19.2Mbps; to compare the real bitrate with the value of a good quality video, we could do the following:
source 1: 7.4 / 6.9 = 1.07
source 2: 19.2 / 14.4 = 1.33
so we now know that source 1 is 7% better than the good quality required by the formula - just a little bit better, while source 2 is 33% better, a whopping one third... I'd go with the latter, and you?
Audio-only sources
Cinema DTS: sometimes the home video audio track has a different mix in comparison to the theatrical one; using Cinema DTS CD-ROMs, you'll be sure the audio will be THE SAME of the one heard in the theaters! It has a fixed 4:1 compression, 16bit 882Kbps, and when decompressed has about the same quality of home DTS tracks at 1.5Mbps.
DVD-Audio: exceptional quality, uncompressed PCM or lossless MLP; up to 24bit, stereo up to 192KHz, while multichannel 5.1 up to 96KHz.
SACD: on par with DVD-Audio, lossless DLD - uncompressed 5.6Mbps, up to 24bit, multichannel, frequency up to 176.4KHz.
CDDA: good quality, linear PCM 16bit 1.4Mbps stereo 44.1KHz.
HDCD: linear PCM 1.4Mbps stereo 44.1KHz; compared to CDDA, resolution is increased to 20bit.
DTS-CD: multichannel up to 5.1, compressed at 3:1, 44.1KHz, up to 20bit.
Vynil record: depending on the quality of hardware used, it could be captured at 24bit up to 192KHz to retain even the most minute details.
Compact Cassette: quality is quite low; I think that a 16bit 32KHz at around 1Mbps capture will be more than adequate.
MiniDisc: usually recorded at 44.1Khz 16bit, like CDDA, but compressed with ATRAC-3, around 4:1.
Same considerations written about video quality should be taken in account for audio; eventual noise, dynamic range etc. could make the difference; would you prefer a 24bit 192KHz track with some noise, or a perfect 16bit 44.1KHz with no noise floor?
Audio/video sources
UHD-BD: the best source up to date: video resolution up to 3840x2160, bitrate up to 128mbps, 10bit color depth, HDR; audio tracks are usually lossless compressed, 7.1 channels - Dolby Atmos, DTS:X, plus all the others available on normal BDs.
BD: still one of the best source; video resolution is up to 1920x1080, bitrate up to 40Mbps; audio tracks could be uncompressed - PCM - or better compressed with a lossless codec to spare a lot of space without losing quality - Dolby Atmos, DTS:X, DTS-HD MA, Dolby TrueHD - or lossy encoded - Dolby Digital, Dolby Digital Plus, Dolby Digital EX up to 640kbps, DTS, DTS-HR, DTS-96, DTS-ES up to 1536kbps - all of them up to 8 channels.
HD-DVD: even if today is a dead format, and almost all titles are available on BD, sometimes there are few titles better than their BD counterparts; video quality is very high, with bitrate up to 30Mbps; audio is similar to BD, with DTS-HD MA at a lower max bitrate, but Dolby Digital Plus at almost double in comparison to BD.
D-Theater: another dead format, this time on tape; few titles released, almost all (if not everyone) on BD, but sometimes there are some little jems to discover; good video quality, bitrate around 20/22Mbps but only MPEG2; audio could be AC-3 or DTS 1.5Mbps.
HDTV: a lot of titles still not present on BD or other HD discs, and many times if they are available, the TV version is different or has different grading or cropping; quality could be really high - ATSC is 1080i MPEG2 at 19.2Mbps, while audio has usually lower quality than other HD sources.
DVD: the most successful digital disc format, present everywhere; very often the same title has different features depending on editions and/or country; quality is good, but not HD; video could be up to 720x480 for NTSC and 720x576 for PAL, anamorphic or not; audio is almost everytime Dolby Digital, but sometimes DTS, usually at half rate, 768Kbps.
VCD: widespread in Asia but not so common in the western countries; some titles could still be available only on this format; video quality is low, MPEG1 352x240 for NTSC and 352x288 for PAL at 1.15mbps fixed bitrate; audio is MPEG stereo 224Kbps at 44.1KHz.
SVCD: rarer than VCD, its predecessor, but with higher quality: video is MPEG2 480x480 for NTSC, 480x576 for PAL, up to 2.6Mbps, audio is usually stereo, but could be up to 6 channels, MPEG up to 384Kbps
Digital streaming: quality varies, from bad SD to very good HD - that could be 720p or 1080p - to great UHD; video bitrates are quite low in comparison to BD and HDTV, but often high enough to obtain good quality; audio could be multichannel, but again usually not on par with BD.
LD: very important format in the past, and with so many titles is quite easy to find out some title never released on DVD or BD; when captured using good players and capture device, quality could be quite good; video resolution could be up to 564x480 for NTSC and 564x576 for PAL; audio could be stereo, analog or PCM 1.44Kbps, or multichannel AC-3 384Kbps or DTS 1.44Kbps.
VHS: once the king of home video, discontinued since few years; sometimes it could be the only way to obtain some particular title; video captured with good VHS, or better S-VHS player or recorder, could be up to 352x480 for NTSC and 352x576 for PAL; audio mono is the norm, but many movies has a stereo Hi-Fi audio track of good quality.
CED, VHD: super-niche formats, video quality is somehow better than VHS but worse than LD; audio could be comparable with VHS Hi-Fi stereo.
Of course, a SD source could be hardly better than an HD one, but how to choose between sources with similar quality? There are some things to take in account: eventual problems like noise reduction, edge enhancement, grain (or the loss of), color grading... if every aspect is similar between the two, bitrate could be a good quality indicator; at the end, you could always use the following formula to know if the bitrate of your source is good enough...
A good digital video should have a bitrate equal or better than
width x height x FPS x motion rank x constant = final bitrate in bps
where the constant should be equal or higher* than
- 0.045 for HEVC
- 0.070 for AVC
- 0.075 for VC-1
- 0.116 for MPEG-2 (hardware encoders)
- 0.136 for MPEG-2 (software encoders)
and the motion rank is equal to
- 1 for low motion (e.g. news)
- 2 for medium motion (e.g. movie)
- 3 for quite high motion (e.g. action movie)
- 4 for high motion (e.g. sport)
Source 1 is 1920x1080, 23.976fps, motion rank 2, encoded in AVC; to have a good quality the bitrate should be:
1920 x 1080 x 23.976 x 2 x 0.07 = 6960328bps = ~6.9Mbps
Source 2 is 1920x1080, 29.96fps, motion rank 2, encoded in MPEG2; to have a good quality the bitrate should be:
1920 x 1080 x 29.96 x 2 x 0.116 =14413012bps = ~14.4Mbps
we discover that source 1 has an average bitrate of 7.4Mbps, while source 2 has a constant bitrate of 19.2Mbps; to compare the real bitrate with the value of a good quality video, we could do the following:
source 1: 7.4 / 6.9 = 1.07
source 2: 19.2 / 14.4 = 1.33
so we now know that source 1 is 7% better than the good quality required by the formula - just a little bit better, while source 2 is 33% better, a whopping one third... I'd go with the latter, and you?
Audio-only sources
Cinema DTS: sometimes the home video audio track has a different mix in comparison to the theatrical one; using Cinema DTS CD-ROMs, you'll be sure the audio will be THE SAME of the one heard in the theaters! It has a fixed 4:1 compression, 16bit 882Kbps, and when decompressed has about the same quality of home DTS tracks at 1.5Mbps.
DVD-Audio: exceptional quality, uncompressed PCM or lossless MLP; up to 24bit, stereo up to 192KHz, while multichannel 5.1 up to 96KHz.
SACD: on par with DVD-Audio, lossless DLD - uncompressed 5.6Mbps, up to 24bit, multichannel, frequency up to 176.4KHz.
CDDA: good quality, linear PCM 16bit 1.4Mbps stereo 44.1KHz.
HDCD: linear PCM 1.4Mbps stereo 44.1KHz; compared to CDDA, resolution is increased to 20bit.
DTS-CD: multichannel up to 5.1, compressed at 3:1, 44.1KHz, up to 20bit.
Vynil record: depending on the quality of hardware used, it could be captured at 24bit up to 192KHz to retain even the most minute details.
Compact Cassette: quality is quite low; I think that a 16bit 32KHz at around 1Mbps capture will be more than adequate.
MiniDisc: usually recorded at 44.1Khz 16bit, like CDDA, but compressed with ATRAC-3, around 4:1.
Same considerations written about video quality should be taken in account for audio; eventual noise, dynamic range etc. could make the difference; would you prefer a 24bit 192KHz track with some noise, or a perfect 16bit 44.1KHz with no noise floor?