Tweet
Boils down to...
At this point, I would say there are too many "qualifications" to make any "definitive" statements. Qualifications such as:
1) Ulead's version of MC's mpeg encoder as found in MSP 7.0 is the best tool for encoding (no other software encoders can produce better quality)
2) 18.1" TFT screens are the best for making the comparison
3) PAL vs. NTSC Colorspace (PAL being identical to mpeg-2, while NTSC is different)
4) only 1-pass VBR was used
5) Source video is the best subject matter (or most challenging to encode)?
6) this applies to DV source (or lower quality)
7) 17 seconds of video is enough to make the generalized statement
8) Other?
I would suggest that folks will use transitions rather than cuts from time to time. I'm only talking about cross fades or fade to/from black. As noted by JM, these areas often show signs of artefacts (as I too have seen them many times on broadcast digital cable, as well as my own encodes at lower bitrates). Granted, they are not true DV Source material since they are rendered into the video, but to encode with higher bitrates (even smaller GOP's at those segments) could prove beneficial in encoding the fades to/from black.
So, what would the the original assumption boil down to? I would argue that it boils down to a comparison between 6000kbps vs. 8500kbps (both CBR). Why do I say this? Because what is being suggested is that at any point where the VBR actually hit 8.5mbps, that it has no benefit over the exact same frame in the 6mbps encode.
What I would suggest is to encode a video at 8.5mbps CBR and 6mbps CBR (at least a few minutes with transitions such as fade to/from black, and a mix of slow/fast moving subject matter). Granted, the higher bitrate might cause a DVD Player to choke/jitter upon playback, but right now the comparison is the resulting video quality. Then, at any point during the videos, the assumption (which I can't accept yet) is NONE of the frames in the 8.5mbps encode are better than the 6mbps video (yes, 8.5mbps CBR can be used, because if it were VBR with 8.5mbps max., then at some point one can expect a frame to hit the max allowable bitrate in the VBR encode). That's why I suggested in my original reply to compare a frame from the VBR file that actually hit the max bitrate vs. the same frame in the CBR file -- if the scene that hit the max bitrate didn't call for it, then that could be a flaw in the encoder, or a multi-pass VBR encode might have done a better job at allocating bits.
With all this said, it turns out that I tend to use between 6-7mbps CBR encoding anyway (all my source has been DV or lower). BUT, I do see artefacts in the final encodes (especially on crossfades and fades to/from black and high-motion scenes). And I am thinking that those scenes could have been managed better with things like (multi-pass VBR, better encoder, customized encoding, spatial/temporal filtering, etc...). Certainly, if I were going to use the final encode as an archive (which I don't), I would rather have an 8.5mbps file over the 6mbps file (unless my source is VHS video, in which case 5-6mbps is probably overkill).
Regards,
George
At this point, I would say there are too many "qualifications" to make any "definitive" statements. Qualifications such as:
1) Ulead's version of MC's mpeg encoder as found in MSP 7.0 is the best tool for encoding (no other software encoders can produce better quality)
2) 18.1" TFT screens are the best for making the comparison
3) PAL vs. NTSC Colorspace (PAL being identical to mpeg-2, while NTSC is different)
4) only 1-pass VBR was used
5) Source video is the best subject matter (or most challenging to encode)?
6) this applies to DV source (or lower quality)
7) 17 seconds of video is enough to make the generalized statement
8) Other?
I would suggest that folks will use transitions rather than cuts from time to time. I'm only talking about cross fades or fade to/from black. As noted by JM, these areas often show signs of artefacts (as I too have seen them many times on broadcast digital cable, as well as my own encodes at lower bitrates). Granted, they are not true DV Source material since they are rendered into the video, but to encode with higher bitrates (even smaller GOP's at those segments) could prove beneficial in encoding the fades to/from black.
So, what would the the original assumption boil down to? I would argue that it boils down to a comparison between 6000kbps vs. 8500kbps (both CBR). Why do I say this? Because what is being suggested is that at any point where the VBR actually hit 8.5mbps, that it has no benefit over the exact same frame in the 6mbps encode.
What I would suggest is to encode a video at 8.5mbps CBR and 6mbps CBR (at least a few minutes with transitions such as fade to/from black, and a mix of slow/fast moving subject matter). Granted, the higher bitrate might cause a DVD Player to choke/jitter upon playback, but right now the comparison is the resulting video quality. Then, at any point during the videos, the assumption (which I can't accept yet) is NONE of the frames in the 8.5mbps encode are better than the 6mbps video (yes, 8.5mbps CBR can be used, because if it were VBR with 8.5mbps max., then at some point one can expect a frame to hit the max allowable bitrate in the VBR encode). That's why I suggested in my original reply to compare a frame from the VBR file that actually hit the max bitrate vs. the same frame in the CBR file -- if the scene that hit the max bitrate didn't call for it, then that could be a flaw in the encoder, or a multi-pass VBR encode might have done a better job at allocating bits.
With all this said, it turns out that I tend to use between 6-7mbps CBR encoding anyway (all my source has been DV or lower). BUT, I do see artefacts in the final encodes (especially on crossfades and fades to/from black and high-motion scenes). And I am thinking that those scenes could have been managed better with things like (multi-pass VBR, better encoder, customized encoding, spatial/temporal filtering, etc...). Certainly, if I were going to use the final encode as an archive (which I don't), I would rather have an 8.5mbps file over the 6mbps file (unless my source is VHS video, in which case 5-6mbps is probably overkill).
Regards,
George
Comment