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Issues with MPEG Streamclip

cannot trim clips

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#1 Patrick Cooper

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Posted 18 January 2013 - 03:17 AM

Recently, Ive been using MPEG Streamclip to compress some time lapse sequences and I'm quite happy with the results. However, today, I have tried to use the trimming feature of this software but I'm having issues with the playback. Firstly, the playback is very jerky which makes it hard to determine which points in the video to select for the 'in' and 'out' points.

Secondly, the online instructions tell you to drag the playhead to these points but there is no playhead in the playback window. When playing the video, I was assuming that there would be something moving along the window near the bottom to indicate the progression of the video but there is nothing like that. Another thing that I find puzzling, and frustrating as well, is that while playing the video, there doesn't seem to be any way of stopping it. I do note that there is a 'pause' icon but it doesn't work. I click 'pause' at least five times and nothing happens. Could there possibly be another window which is used specifically for trimming / editing? Ive gone through the menu options but can't seem to find it - if it does exist
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#2 Phil Rhodes

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Posted 18 January 2013 - 05:40 AM

Playing back timelapse sequences from a stack of frames without having rendered it down to a file first quite frequently causes performance problems. There is no particular technical reason why this should be so, but it often is; it's simply a failure in the amount of care that's put into making the file reader fast enough.

I'm not familiar enough with Streamclip to comment on your other issue, but you can do still sequence assembly in almost any piece of edit software you like; have you tried using something else?
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#3 Patrick Cooper

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Posted 18 January 2013 - 10:37 PM


Phil Rhodes: "Playing back timelapse sequences from a stack of frames without having rendered it down to a file first quite frequently causes performance problems."

Ah but this particular clip is not a time lapse sequence. It's footage from my GoPro Hero 3. I have figured out a way to edit it though. I still can't access most of the trimming facilities in MPEG Streamclip but there is an option for entering in the timecode for the 'in' and 'out' points and it creates the selection from that. The plan is to upload the trimmed clip to youtube, and for rendering, I thought I would use the same settings that I use for the time lapse sequences. In other words, save the file as a MOV, use the h.264 codec with a bit rate of 5000 kbps. However, the quality was pretty crappy. There are blocked shaped artifacts which are most noticeable in the blue sky. What actually causes these blocky artifacts? Is it the codec, the bit rate or a combination of both? I don't want to increae the bit rate too much higher because 5000 kbps is what's recommended for youtube and vimeo upload.

The GoPro website recommends use of the Apple ProRes codec when using MPEG Streamclip but I can't find that particular codec on this software. I gave Apple MPEG4 Compressor a go, using the same bit rate. The finished video was better quality compared to when I used the h.264 codec. At first, I couldn't see any artifacts in the blue sky in the video. Though after a while, and looking very carefully, I could make out some slight banding in the sky. So it looks like there is still some room for improvement.

Phil Rhodes: "I'm not familiar enough with Streamclip to comment on your other issue, but you can do still sequence assembly in almost any piece of edit software you like; have you tried using something else?"

The only other video editing software that I have is VideoRedo though that can't open GoPro footage.


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#4 Phil Rhodes

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Posted 19 January 2013 - 09:04 AM

I still can't access most of the trimming facilities in MPEG Streamclip



Can't help you, sorry. If I wanted to edit something, I'd use editing software! Streamclip is more a conversion tool; I think you may simply be hitting the limits of its capabilities.

I thought I would use the same settings that I use for the time lapse sequences. In other words, save the file as a MOV, use the h.264 codec with a bit rate of 5000 kbps. However, the quality was pretty crappy.



Is this HD or SD stuff? 5Kbps is reasonably generous for SD, but high def material typically wants two or three times that to look reasonable. The h.264 compressor in Quicktime is not the best in the world but it should be able to do a workmanlike job given sufficient bitrate. Quality of the input material also matters; GoPro stuff is already quite heavily compressed.

The GoPro website recommends use of the Apple ProRes codec when using MPEG Streamclip but I can't find that particular codec on this software.



Are you using Windows? ProRes encoding is only available in Quicktime if you're on a Mac. If you must create ProRes, you can do so on any platform using the free tool ffmpeg, with a command such as:

ffmpeg -i infile.mov -vcodec prores -profile std outfile.mov

...where "std" is one of proxy, lt, std or hq.

However, if all you need is an intermediate format, there are other codecs you could use, or simply keep it uncompressed if you have the disk space (also, almost anything can read uncompressed files). However, this won't help you upload it to the internet; any intermediate codec will create impractically large files.

I gave Apple MPEG4 Compressor a go



h.264 is MPEG-4 part 10, so "Apple MPEG-4 Compressor" and Quicktime's h.264 compressor may be synonymous. I'm not sure - there may be differences, but I'd be surprised if the performance was wildly different for the same settings.

The finished video was better quality compared to when I used the h.264 codec. At first, I couldn't see any artifacts in the blue sky in the video. Though after a while, and looking very carefully, I could make out some slight banding in the sky. So it looks like there is still some room for improvement.



It's never going to be completely lossless. At the sort of bitrates suitable for use on the internet, some visible degradation is inevitable, especially if the material has already been compressed.

The only other video editing software that I have is VideoRedo though that can't open GoPro footage.



Never heard of it. I'd do this in Premiere, in which situation you would simply import the material directly, edit to taste, and export the h.264.

P
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