Video is refusing to play - Keyframe issue?

[jairovital]

Hi, folks.

Now, the problem is how to cut properly a mpeg2 stream. I have this video:
http://www.4shared.com/video/SDe-1lgS/Keyframe.html
from a TV capture. Sorry for the bad quality.

I use to cut it with Womble Mpeg Video Wizard. The most of videos, I can convert to RMVB using EasyRealMediaProducer (ERMP). But few of them refuses to play after conversion. Like this one:
http://www.4shared.com/file/c7JINtVO/Keyframe.html
from the previous source above.

I tried navigate on keyframes (I-frames) with Womble, but I didn't find how to. I suspect that the problem with few videos refusing to play is because of lack of care with I-frames. I don't understand why the first frame of a video is not a keyframe. I think it is, but what's the problem, then? Or, why the resulting video doesn't play.

If I use Avidemux to create an AVI video with the same source, the resulting video plays fine.

Some questions:
1 - Why ERMP creates a file that won't play?
2 - Why ERMP creates some files that play fine? (with the exactly same parameters - default)
3 - Is the problem with keyframes? Or with ERMP?
4 - How to navigate by keyframes using Womble?
5 - How to navigate by keyframes using Mpeg StreamClip? (CTRL-K) goes to it, but stops on it, and << >> buttons forwards 10 secs, not keyframes.

[aedipuss]

why do you convert to rmvb? it's about the worst format ever invented.

[jairovital]

why do you convert to rmvb? it's about the worst format ever invented.

Because I don't care with quality for some videos and it can reduce the file size to half or more. But other stuffs I use x264 and quantization matrix.

BTW, do you have some answers for the questions?

[poisondeathray]

It plays fine here in every player

Probably something wrong with your playback setup

You will get better quality and smaller filesize with the optimal x264 settings and if you prefilter

[jairovital]

It plays fine here in every player

???

Probably something wrong with your playback setup

Or it'll be driving me to another codec nightmare...

[jairovital]

Thank you, poisondeathray, for your kind and prompt response. May you explain questions 4 and 5?

[poisondeathray]

mpc, mpchc, vlc , kmplayer, smplayer all play it fine

vlc and smplayer do not rely on system installed codecs, test with those

May you explain questions 4 and 5?

Womble smart renders, so it doesn't matter where you cut
Not sure about mpegstreamclip

[jairovital]

vlc and smplayer do not rely on system installed codecs, test with those

Yes, you're right! VLC plays fine. I was trying with GomPlayer, codec based.

Womble smart renders, so it doesn't matter where you cut.

Good to know. But sometimes I try to open a file with Avidemux (not from Womble source) and it says it needs to rebuild index. After that, the first frame is not I-frame, but P-frame. How is it possible to have a video file which first frame is not a keyframe? And how to deal with that? Cutting more?

ERMP has an editing tool and the solution I found is to cut some ms ahead and try again, until it plays fine. Because of that, I was guessing that the problem was related with keyframes.

Not sure about mpegstreamclip

Never mind.

[poisondeathray]

But sometimes I try to open a file with Avidemux (not from Womble source) and it says it needs to rebuild index. After that, the first frame is not I-frame, but P-frame. How is it possible to have a video file which first frame is not a keyframe? And how to deal with that? Cutting more?

Display order is not always the same as encoding order (frames can be stored in different order than which they are displayed) . It shouldn't matter with most software. If you need an I-frame (display or encoded order), then cut on I-frames on the original source (e.g use mpg2cut2 or avidemux to cut)


For the directshow playback issue , you can try enabling rmvb in ffdshow, or maybe install real alternative

[jairovital]

If you need an I-frame (display or encoded order), then cut on I-frames on the original source (e.g use mpg2cut2 or avidemux to cut)

Sometime with videos from vimeo I get those "rebuild index needed" warning when openning with avidemix. If I try to cut in the next I-frame I would lost too many frames before. Nothing to do with this? Is not possible to force avidemux to process (creates) a video before that next I-frame?

avidemux says "first frame must to be an I-frame".

[poisondeathray]

Sometime with videos from vimeo I get those "rebuild index needed" warning when openning with avidemix. If I try to cut in the next I-frame I would lost too many frames before. Nothing to do with this? Is not possible to force avidemux to process (creates) a video before that next I-frame?

1) Vimeo doesn't use mpeg2, it uses h.264
2) avidemux cannot smart render h.264 (cannot make frame accurate cuts) , use something else like videoredo beta , or solveigmm (these 2 are not free)

or , if you are re-encoding anyway, then specify your cuts in something like avisynth


In general, if you use closed GOP's , then every frame within that GOP will only be referenced within that GOP (i.e. there will be no references to frames outside of that GOP) - so if you "cut on keyframes" (technically it's right before the keyframe), every cutsite will begin with an I-frame

[jairovital]

Great! Answered all my doubts!

[jairovital]

2) avidemux cannot smart render h.264 (cannot make frame accurate cuts) , use something else like videoredo beta , or solveigmm (these 2 are not free)

I thought the thread was closed, but following your advice, I got videoredo 3 beta (trial) and it says:
"H.263/AVC video streams are not supported in this version"

Going to test solveigmm...

[poisondeathray]

2) avidemux cannot smart render h.264 (cannot make frame accurate cuts) , use something else like videoredo beta , or solveigmm (these 2 are not free)

I thought the thread was closed, but following your advice, I got videoredo 3 beta (trial) and it says:
"H.263/AVC video streams are not supported in this version"

Going to test solveigmm...

for videoredo you need version 4.x, not 3

videoredo tv suite h.264 4.x
http://www.videoredo.com/en/index.htm

[jairovital]

for videoredo you need version 4.x, not 3

Videoredo 4 beta says:
"MPEG audio Layer 1 is not supported"

Also: it crashes when I try to close application.

SolveigMM is OK. Opened it without question. Thinking to buy it. But if Avidemux plans to make frame accurate cuts in a close future...