--- On Mon, 4/2/12, Ichthyostega <p...@ichthyostega.de> wrote: From: Ichthyostega <p...@ichthyostega.de> Subject: Re: [CinCV] Confused about ffmpeg -vf crop=h:w:x:y To: cinelerra@skolelinux.no Received: Monday, April 2, 2012, 4:41 PM
Am 02.04.2012 06:56, schrieb Murray Strome: > I have a video which is .mpg 720X480, 16:9 with the active video centred and > smaller than the full frame. I tried two things: > 1. ffmpeg -i <In.mpg> -s hd720 -b 8500k <out.mpg> > 2. ffmpeg -i <in.mpg> -vf crop=540:304 -vf scale=1280:720 -s hd720 -b 8500k > <out.mpg> > I don't see any difference in the resulting two videos when I play them back > in any of the LINUX video players on my LINUX distribution, nor any of the > video players I see in Windows. The second command specifies explicitly what to do, while the first command just states "I want hd720 video output". Thus, some default behaviour of ffmpeg kicks in here. My guess ist that this default behaviour does the same as the explicitly specified processing instructions in the second command. But wait -- doesn't ffmpeg print detailed diagnostics on what it actually does while transforming the video. Maybe we could figure out from this output what is actually done to the video stream? Hermann V Hi Herman, Here is an example of the first part of the message. Here the video is 352X480 aspect 4:3 and I want to get a result which cuts off the black bands at the top and bottom. I am assuming that the crop is supposed to work on the input video, so I set the crop to keep the original width but remove the top and bottom, then rescale. From this output, (and similar output from others with the 720X480 size input) it would appear to me that the -vf crop is being completely ignored. The question is, "Why?" Murray $ ffmpeg -i VTS_01_1.VOB -vf crop=352:270:0:0 -vf scale=1280:720 -s hd720 -b 8500k WC-VOB-1B.mpg ffmpeg version 0.7.3-4:0.7.3-0ubuntu0.11.10.1, Copyright (c) 2000-2011 the Libav developers built on Jan 4 2012 16:08:51 with gcc 4.6.1 configuration: --extra-version='4:0.7.3-0ubuntu0.11.10.1' --arch=amd64 --prefix=/usr --enable-vdpau --enable-bzlib --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --enable-zlib --enable-libvpx --enable-runtime-cpudetect --enable-vaapi --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --enable-libdc1394 --enable-shared --disable-static WARNING: library configuration mismatch avutil configuration: --extra-version='4:0.7.3ubuntu0.11.10.1+medibuntu1' --arch=amd64 --prefix=/usr --enable-vdpau --enable-bzlib --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --enable-zlib --enable-libvpx --enable-runtime-cpudetect --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-version3 --enable-vaapi --enable-libopenjpeg --enable-libfaac --enable-nonfree --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --enable-libdirac --enable-libmp3lame --enable-librtmp --enable-libx264 --enable-libxvid --enable-libopencore-amrnb --enable-version3 --enable-libopencore-amrwb --enable-version3 --enable-libvo-aacenc --enable-version3 --enable-libvo-amrwbenc --enable-version3 --enable-libdc1394 --enable-shared --disable-static avcodec configuration: --extra-version='4:0.7.3ubuntu0.11.10.1+medibuntu1' --arch=amd64 --prefix=/usr --enable-vdpau --enable-bzlib --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --enable-zlib --enable-libvpx --enable-runtime-cpudetect --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-version3 --enable-vaapi --enable-libopenjpeg --enable-libfaac --enable-nonfree --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --enable-libdirac --enable-libmp3lame --enable-librtmp --enable-libx264 --enable-libxvid --enable-libopencore-amrnb --enable-version3 --enable-libopencore-amrwb --enable-version3 --enable-libvo-aacenc --enable-version3 --enable-libvo-amrwbenc --enable-version3 --enable-libdc1394 --enable-shared --disable-static libavutil 51. 7. 0 / 51. 7. 0 libavcodec 53. 6. 0 / 53. 6. 0 libavformat 53. 3. 0 / 53. 3. 0 libavdevice 53. 0. 0 / 53. 0. 0 libavfilter 2. 4. 0 / 2. 4. 0 libswscale 2. 0. 0 / 2. 0. 0 libpostproc 52. 0. 0 / 52. 0. 0 [mpeg @ 0x2109560] max_analyze_duration reached Input #0, mpeg, from 'VTS_01_1.VOB': Duration: 01:00:10.37, start: 0.521789, bitrate: 2379 kb/s Stream #0.0[0x1e0]: Video: mpeg2video (Main), yuv420p, 352x480 [PAR 20:11 DAR 4:3], 3758 kb/s, 29.97 fps, 29.97 tbr, 90k tbn, 59.94 tbc Stream #0.1[0x80]: Audio: ac3, 48000 Hz, stereo, s16, 256 kb/s [buffer @ 0x210b520] w:352 h:480 pixfmt:yuv420p [scale @ 0x210b1e0] w:352 h:480 fmt:yuv420p -> w:1280 h:720 fmt:yuv420p flags:0x4 [scale @ 0x210fec0] w:1280 h:720 fmt:yuv420p -> w:1280 h:720 fmt:yuv420p flags:0x4 [mpeg @ 0x2107940] VBV buffer size not set, muxing may fail Output #0, mpeg, to 'WC-VOB-1B.mpg': Metadata: encoder : Lavf53.3.0 Stream #0.0: Video: mpeg1video, yuv420p, 1280x720 [PAR 20:11 DAR 320:99], q=2-31, 8500 kb/s, 90k tbn, 29.97 tbc Stream #0.1: Audio: mp2, 48000 Hz, stereo, s16, 64 kb/s Stream mapping: Stream #0.0 -> #0.0 Stream #0.1 -> #0.1 Press ctrl-c to stop encoding I guess the main issue is that the video is not cropped. As I said in an earlier post, under the old ffmpeg, to achieve the result I want, I would have done: -cropleft 90 -cropright 90 ... etc and the video would be cropped then the result scaled to fit the frame. I can see that no cropping was done at all.
