I address your points below. When I refer to "Tailor", I mean FutureTel's frame-accurate MPEG editing engine, which is integrated into both the VideOh! and the Video Sphinx Pro products. Tailor is a cut-and-paste non-real-time editor. Tailor includes support for special effects, two of which (Fades and Titling or both) are integrated into ClipView 2.0. The current implementation of Effects is a complete re-encode (but a careful one, in the VBV sense) over the effect duration.
You might also like to read my reply to Halstead York on this topic.
At 12:02 AM 10/3/98 PDT, Chris O'Leary wrote:
>My concern is that you have to accept one of several limitations when
>you talk about editing MPEG. The first limitation is that editing a
>standard MPEG stream will likely cause a video buffer overflow - which
>will mean that the stream will be rendered illegal and cannot be played
>back from that point on.
Correct, but Tailor takes pains about this.
>You can get around in several ways. You can lower your bit rate or inject blank frames, but this will impact quality.
Correct, but Tailor does not do either of these things.
>You could also re-encode the clip from the point of the edit,
>but that can be a hassle, especially when you are dealing with longer
>clips.
Correct, but Tailor does not do this either.
>The third option is to do what is called an I-frame only encode.
>This is to encode the sequence using only MPEG I-frames and not P-frames
>and B-frames. The problem is that an I-frame only encode is basically
>the same as a motion-JPEG encode. The point of MPEG is that is looks
>for opportunities to compress both within (intraframe) and between
>(interframe) frames. With an I-frame only encode you aren't using any
>interframe compression, so your file won't be as small as a standard
>MPEG file. A fully-encoded stream with I, P, and B frames could be 5 to
>10 percent of the size of a comparable I-frame only or motion-JPEG
>encode. The point of MPEG is that its files are smaller than
>motion-JPEG files but are of comparable quality.
Correct, but Tailor is a full IBP editor, so the above does not apply.
>The bottom line is that MPEG editing is possible, but is very hard to
>ensure that the file will be small, high-quality, legal, and not have to
>be re-encoded.
Then I guess we did the very hard thing.
Cheers,
Andrew