symonjfox
5th March 2003, 14:39
Hi. Last night I had an idea but I'm sure it is not possible.
Now I explain:
I was reading/posting in a topic where we're talking about VBR audio in SVCD. As everybody knows, SVCD has some limits in the total bitrate (2720 kbs to be sure of compilance), so we must use VBR stuff with care.
For example,
let's suppose I create a MPV track VBR with MAX BITRATE 2560 kbs.
in theory the max allowed bitrate for audio is 160 kbs.
Using these settings, the SVCD will be compilant and everything is ok
Now let's suppose I want to create a VBR audio track for this disc. To be compilant, the MAX bitrate should be 160 kbs.
Using the last TooLame with VBR settings, the bitrate always goes from 112 to 224 kbs (sometimes up to 320, depends on settings and soruces).
If I keep this file (max brt 224) this disc will have troubles when the TOTAL bitrate jumps out of specs. This will append on action scenes (where both audio and video are more complex: let's suppose an explosion, a shot or other stuff).
Here's my idea. If I delay the audio a little bit, the video and audio peaks won't arrive at the same time, but the total bitrate could be respected (not always but this setting could be improved a lot: let's suppose about analizing all Audio file and Video file and then performing some calculations ... all before muxing).
The matter is that I don't know how to play it back in A/V synch.
I saw that some DVDs does this thing (delay audio) and so I guess why SVCD can't?
Now I explain:
I was reading/posting in a topic where we're talking about VBR audio in SVCD. As everybody knows, SVCD has some limits in the total bitrate (2720 kbs to be sure of compilance), so we must use VBR stuff with care.
For example,
let's suppose I create a MPV track VBR with MAX BITRATE 2560 kbs.
in theory the max allowed bitrate for audio is 160 kbs.
Using these settings, the SVCD will be compilant and everything is ok
Now let's suppose I want to create a VBR audio track for this disc. To be compilant, the MAX bitrate should be 160 kbs.
Using the last TooLame with VBR settings, the bitrate always goes from 112 to 224 kbs (sometimes up to 320, depends on settings and soruces).
If I keep this file (max brt 224) this disc will have troubles when the TOTAL bitrate jumps out of specs. This will append on action scenes (where both audio and video are more complex: let's suppose an explosion, a shot or other stuff).
Here's my idea. If I delay the audio a little bit, the video and audio peaks won't arrive at the same time, but the total bitrate could be respected (not always but this setting could be improved a lot: let's suppose about analizing all Audio file and Video file and then performing some calculations ... all before muxing).
The matter is that I don't know how to play it back in A/V synch.
I saw that some DVDs does this thing (delay audio) and so I guess why SVCD can't?