dwallersv
8th June 2008, 05:13
Okay... so I have an x264 stream that I'd like to edit without having to recode, saving lots of time. I do this on MPEG2 streams using VideoRedo (an excellent tool!), but unfortunately it doesn't support ASP or AVC yet.
Can-do with Avidemux (another excellent tool!). However, avidemux doesn't handle B-frames in ASP/AVC streams gracefully. In theory, I should be able to perform frame-accurate edits so long as I keep the cuts on I-frames, and then save the edited stream using the copy mode, creating an edited stream without recoding (and getting it done in literally a minute or so for an hour of video).
All good so far. Here's the problem: avidemux doesn't seek in a clean, predictable way due to the packed GOPs in these formats. So even when I advance I-frame by I-frame, I don't get consistent results -- I don't always land on an I-frame! Then, backing up or going forward a frame to get to the I-frame is goofy -- clearly the packed GOPs and B-frames are being handled weirdly.
So, here's the question: Anyone have advice/techniques for how to set markers in avidemux to make a clean cut between two I-frames (not necessarily consecutive)? I can do it, but it takes a lot of seeking back and forth with the I-frame fwd/back, and single frame fwd/back, until I get a clean display of the individual frames in the right order, can stop on the starting keyframe, mark it, go to the ending keyframe (then seek back and forth over and over like before), back up to the P/B frame right before the ending keyframe, mark it, then cut.
This works, but it's a lot of awkward effort. Worth it to preserve quality and save time avoiding recoding, but I'd love a simpler, more straightforward way to do this.
I've got one of those new Hauppauge HD PVR thingies on the way due tuesday, so I'll be doing a lot more h264 editing soon. Right now, it's a bit of a pain with the partially supported packed bitstream support in avidemux.
Thanks!
(please forgive me in advance if I've munged any of the terminology... I'm learning)
Can-do with Avidemux (another excellent tool!). However, avidemux doesn't handle B-frames in ASP/AVC streams gracefully. In theory, I should be able to perform frame-accurate edits so long as I keep the cuts on I-frames, and then save the edited stream using the copy mode, creating an edited stream without recoding (and getting it done in literally a minute or so for an hour of video).
All good so far. Here's the problem: avidemux doesn't seek in a clean, predictable way due to the packed GOPs in these formats. So even when I advance I-frame by I-frame, I don't get consistent results -- I don't always land on an I-frame! Then, backing up or going forward a frame to get to the I-frame is goofy -- clearly the packed GOPs and B-frames are being handled weirdly.
So, here's the question: Anyone have advice/techniques for how to set markers in avidemux to make a clean cut between two I-frames (not necessarily consecutive)? I can do it, but it takes a lot of seeking back and forth with the I-frame fwd/back, and single frame fwd/back, until I get a clean display of the individual frames in the right order, can stop on the starting keyframe, mark it, go to the ending keyframe (then seek back and forth over and over like before), back up to the P/B frame right before the ending keyframe, mark it, then cut.
This works, but it's a lot of awkward effort. Worth it to preserve quality and save time avoiding recoding, but I'd love a simpler, more straightforward way to do this.
I've got one of those new Hauppauge HD PVR thingies on the way due tuesday, so I'll be doing a lot more h264 editing soon. Right now, it's a bit of a pain with the partially supported packed bitstream support in avidemux.
Thanks!
(please forgive me in advance if I've munged any of the terminology... I'm learning)