Hello guys I want to create movie trailers with ffmpeg. I have different size videos from 2 mins to 1 hour. What is the correct way to create trailer ? I want them below given size for example 10-15Mb. What if I capture every one of ten frames.Will it do the job ? Or i have to capture {__} seconds for every 5 mins for example? Please give suggestions Thanks -- Venci Vatashki
On man, 2005-05-30 at 13:45 +0000, Venci Vatashki wrote:
I want to create movie trailers with ffmpeg. [...] What if I capture every one of ten frames.Will it do the job ? Or i have to capture {__} seconds for every 5 mins for example?
I'm not sure exactly what you want, but I guess you want to create a super-fast (like 10x) version some videoclips. My example input has 25 fps. My idea is to claim it is 250, and convert it to 25: ffmpeg -r 250 -i in.mpg -r 25 out.mpg But that doesn't work. Ffmpeg can see it's 25 fps, and ignores my framerate. So I need to convert it to something that has no framerate first: ffmpeg -i mpg %08d.png ffmpeg -r 250 -i %08d.png -r 25 out.mpg To reduce disk usage, you can do something like this: ffmpeg -i mpg %08d.png ffmpeg -r 25 -i %07d0.png -r 25 out.mpg And run this at the same time: while true; do rm ???????{1,2,3,4,5,6,7,8,9}.png; sleep 1; done (Be careful that it doesn't delete anything it shouldn't.) Finally, for a more smooth result, which uses info from all frames: (Needs image magick) ffmpeg -i mpg %08d.png for i in `seq -w 0 100` do echo $i convert 0000$i?.png -average -depth 8 a0000$i.png done ffmpeg -r 25 -i a%07d.png out.mpg This example uses the first 1010 png-images, creating 101 frames of output. -- Kind regards, Niels Andersen
Hi I was wandering is it possible to capture TV shows with ffmpeg under Windows and if not what is the problem ? I did some google but I didn't find anything. Thanks
Hello all, Does ffmpeg have direct stream copy ? I want to crop a video and I dont want to recompress Thanks -- Venci Vatashki
Venci Vatashki wrote:
Hello all, Does ffmpeg have direct stream copy ? I want to crop a video and I dont want to recompress
Yes, it does (-vcodec copy), but I believe you're out of luck anyway - because "direct stream copy" means that the stream will not be altered in any way, which in turn means that you cannot crop it in the process. If you want to crop the video without recompressing, your only option AFAIK is to store the uncompressed video. -- The Wanderer Warning: Simply because I argue an issue does not mean I agree with any side of it. A government exists to serve its citizens, not to control them.
Yes, it does (-vcodec copy), but I believe you're out of luck anyway - because "direct stream copy" means that the stream will not be altered in any way, which in turn means that you cannot crop it in the process. If you want to crop the video without recompressing, your only option AFAIK is to store the uncompressed video.
Hmm are you sure? I tried -vcodec copy but I got only audio.I dont think "copy" is recognized option for ffmpeg.And "direct stream copy" means at least for VirtualDub not the whole stream but no compression/decompression for that stream -- Venci Vatashki
Venci Vatashki wrote:
Yes, it does (-vcodec copy), but I believe you're out of luck anyway - because "direct stream copy" means that the stream will not be altered in any way, which in turn means that you cannot crop it in the process. If you want to crop the video without recompressing, your only option AFAIK is to store the uncompressed video.
Hmm are you sure? I tried -vcodec copy but I got only audio.I dont think "copy" is recognized option for ffmpeg.
It certainly should be - and it is equally certainly there in the man page, at least on my end. What version are you using?
And "direct stream copy" means at least for VirtualDub not the whole stream but no compression/decompression for that stream
I don't know how it would be even possible to modify a compressed stream to produce a known net effect without decompressing that stream - and if you decompress and want to wind up with compressed data, you obviously need to recompress it. "Direct stream copy", in MPlayer and I believe in FFmpeg, appears to mean "byte-for-byte duplication of the input stream". It is inherently impossible to both duplicate a stream byte-for-byte and simultaneously modify that stream in some way. I don't see offhand how any process which incorporates any modification could reasonably be called a direct copy; if you can shed light on that, feel free. -- The Wanderer Warning: Simply because I argue an issue does not mean I agree with any side of it. A government exists to serve its citizens, not to control them.
participants (3)
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inverseparadox＠comcast.net -
niels＠myplace.dk -
vvatashki＠gmail.com