[FFmpeg-user] How to dynamically drop frames as required to keep transcoding real time?
Hi, I have a question that I thought should have an ‘easy’ answer – I have spent a lot of time searching and I cannot find it, so thought I would ask here. My application sounds simple. I have an input RTSP stream, which I need to transcode and output as an RTP stream. Command line is very simple, something like: ./ffmpeg -i rtsp://… -vf scale=1024:-1 -c:v libx264 -f rtp rtp://… Now, ffmpeg is running on a CPU-constrained platform, and it may be that, in order for the transcoding to ‘keep up’ with the input, the output framerate needs to be less than the input framerate, which is totally fine. The problem/question is: how do I get ffmpeg to drop frames as required to keep the pipeline running real time? I can’t simply ‘guess’ a sustainable output framerate and set using -r XXX or -vf fps=fps=XXX, because the properties of the input can change at any time, so any XXX won’t be constant. Besides, if the ‘guess’ is too high for the CPU power I have available, the encoder won’t keep up with the input frames and so will ‘run away’ (i.e. the time difference between each input frame and its corresponding output frame will get bigger and bigger), which is the problem I am trying to solve. On the other hand, if the ‘guess’ is too low, I will end up with real-time output but I will also be potentially transcoding to a lower output frame rate than I have the CPU power to do, which I don’t want either. What I need is some kind of dynamic framerate filter that doesn’t take a number at all (or maybe takes simply a maximum), and drops frames if and only if the encoder can’t keep up … so the pipeline produces as high a frame rate output as possible, while still being real time. I cannot figure out how to do this. Surely this wish can’t be super uncommon as you would imagine it would be quite important in all sorts of streaming applications where unlimited transcoding power is not guaranteed to be available. Can anyone help? -Adrian ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-user] Cut part of a video, crop it and blackout parts of it
Michael Koch writes: > If you want to cover the whole frame size, you could also use this (for > 50% gray): > eq=enable='bitor(between(t, 0, 2),between(t, 339, 342))':contrast=0 > or add :brightness=-0.5 if you want black. > It might be faster than drawbox. It is not faster. It also keeps a 'shadow' of the video. I will play a little more with it, but the change is high that I go back to drawbox. -- Cecil Westerhof Senior Software Engineer LinkedIn: http://www.linkedin.com/in/cecilwesterhof ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-user] Using Homebrew to install FFmpeg, But having wired problems.
On 4/4/21, 9:39 PM, "ffmpeg-user on behalf of Kosei Seki" wrote: (base) XXX-MacBook-Air ~ % brew install ffmpeg --HEAD Updating Homebrew... ==> Installing ffmpeg from homebrew-ffmpeg/ffmpeg ==> Searching for similarly named formulae... Error: No similarly named formulae found. Error: No available formula with the name "nasm" (dependency of homebrew-ffmpeg/ffmpeg/ffmpeg). ==> Searching for a previously deleted formula (in the last month)... Error: No previously deleted formula found. ==> Searching taps on GitHub... Error: No formulae found in taps. How can I solve this problem? Thx This looks promising: https://github.com/Homebrew/discussions/discussions L. Lee ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
[FFmpeg-user] Timestamps are unset in a packet for stream 1. UDP Streaming
Dear all, My video which has KLV metadata on stream 1, is not timestamped properly, when streaming udp. ¿Is there anyway to recreate the timestamps? I am doing something wrong when streaming by udp. The command employed is the following: >>ffmpeg -re -i klv.mpeg -map 0 -codec copy -f mpegts >>udp://127.0.0.1:9000?pkt_size=1316 ffmpeg version N-101612-gda12d600ea Copyright (c) 2000-2021 the FFmpeg developers built with gcc 9.3-win32 (GCC) 20200320 configuration: --prefix=/ffbuild/prefix --pkg-config-flags=--static --pkg-config=pkg-config --cross-prefix=x86_64-w64-mingw32- --arch=x86_64 --target-os=mingw32 --enable-gpl --enable-version3 --disable-debug --enable-shared --disable-static --disable-w32threads --enable-pthreads --enable-iconv --enable-zlib --enable-libxml2 --enable-libfreetype --enable-libfribidi --enable-gmp --enable-lzma --enable-fontconfig --enable-opencl --enable-libvmaf --enable-vulkan --enable-libvorbis --enable-amf --enable-libaom --enable-avisynth --enable-libdav1d --enable-libdavs2 --enable-ffnvcodec --enable-cuda-llvm --enable-libglslang --enable-libgme --enable-libass --enable-libbluray --enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvpx --enable-libwebp --enable-lv2 --enable-libmfx --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librav1e --enable-librubberband --enable-schannel --enable-sdl2 --enable-libsoxr --enable-libsrt --enable-libsvtav1 --enable-libtwolame --enable-libuavs3d --enable-libvidstab --enable-libx264 --enable-libx265 --enable-libxavs2 --enable-libxvid --enable-libzimg --extra-cflags=-DLIBTWOLAME_STATIC --extra-cxxflags= --extra-ldflags=-pthread --extra-libs=-lgomp libavutil 56. 68.100 / 56. 68.100 libavcodec 58.133.100 / 58.133.100 libavformat58. 74.100 / 58. 74.100 libavdevice58. 12.100 / 58. 12.100 libavfilter 7.109.100 / 7.109.100 libswscale 5. 8.100 / 5. 8.100 libswresample 3. 8.100 / 3. 8.100 libpostproc55. 8.100 / 55. 8.100 [mpegts @ 02c852e57000] start time for stream 1 is not set in estimate_timings_from_pts Input #0, mpegts, from 'klv.mpeg': Duration: 00:01:30.80, start: 0.50, bitrate: 1347 kb/s Program 1 Stream #0:0[0x3e8]: Video: mpeg2video (Main) ([2][0][0][0] / 0x0002), yuv420p(tv, bt470bg, progressive), 640x480 [SAR 1:1 DAR 4:3], 30 fps, 30 tbr, 90k tbn, 60 tbc Side data: cpb: bitrate max/min/avg: 100/0/0 buffer size: 1835008 vbv_delay: N/A Stream #0:1[0x90]: Data: klv (KLVA / 0x41564C4B) Output #0, mpegts, to 'udp://127.0.0.1:9000?pkt_size=1316': Metadata: encoder : Lavf58.74.100 Stream #0:0: Video: mpeg2video (Main) ([2][0][0][0] / 0x0002), yuv420p(tv, bt470bg, progressive), 640x480 [SAR 1:1 DAR 4:3], q=2-31, 30 fps, 30 tbr, 90k tbn, 90k tbc Side data: cpb: bitrate max/min/avg: 100/0/0 buffer size: 1835008 vbv_delay: N/A Stream #0:1: Data: klv (KLVA / 0x41564C4B) Stream mapping: Stream #0:0 -> #0:0 (copy) Stream #0:1 -> #0:1 (copy) Press [q] to stop, [?] for help [mpegts @ 02c854add100] Timestamps are unset in a packet for stream 1. This is deprecated and will stop working in the future. Fix your code to set the timestamps properly frame= 31 fps= 30 q=-1.0 size= 66kB time=00:00:01.03 bitrate= 524.0kbits/s speed= 1x P Please consider the environment before printing this e-mail. ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-user] Cut part of a video, crop it and blackout parts of it
Michael Koch writes: > Am 05.04.2021 um 11:58 schrieb Cecil Westerhof via ffmpeg-user: >> Michael Koch writes: >> >>> Am 05.04.2021 um 01:48 schrieb Cecil Westerhof via ffmpeg-user: I have to cut out a part of a video, crop it and blackout two parts. I do this with: ffmpeg -y \ -ss 00:19:49\ -i 2021-03-25ToastmastersClubAvond.mp4 \ -to 442 \ -vf " crop = 1440:1080:240:0 , drawbox=enable='between(t, 0, 2)' : color = black : w = in_w : h = in_h : thickness = fill , drawbox=enable='between(t, 339, 342)' : color = black : w = in_w : h = in_h : thickness = fill " \ -acodec copy\ -vcodec libx264 \ -crf23 \ speechClean2.mp4 The reason I do -to in the output is that in this way the metadata concerning the video length is less out of whack. I was wondering if this is a good way, or that it could be done better? Also, beside the timestamps the parameters for drawbox are the same. Is there a way that I do not have to repeat them? >>> drawbox=enable='bitor(between(t, 0, 2),between(t, 339, 342))' >> Works like a charm. >> >> Strange thing is that it seems to be much faster. About 20%. To much >> to be because of different load I think. >> But I am not complaining. ;-) > > If you want to cover the whole frame size, you could also use this (for > 50% gray): > eq=enable='bitor(between(t, 0, 2),between(t, 339, 342))':contrast=0 > or add :brightness=-0.5 if you want black. > It might be faster than drawbox. I will try that out later. At the moment I am working with the different preset values. It seems that veryfast is still the best. And that you really should not use ultrafast. -- Cecil Westerhof Senior Software Engineer LinkedIn: http://www.linkedin.com/in/cecilwesterhof ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-user] Cut part of a video, crop it and blackout parts of it
Cecil Westerhof via ffmpeg-user writes: > I have to cut out a part of a video, crop it and blackout two parts. > I do this with: > ffmpeg -y \ >-ss 00:19:49\ >-i 2021-03-25ToastmastersClubAvond.mp4 \ >-to 442 \ >-vf " > crop = 1440:1080:240:0 > , > drawbox=enable='between(t, 0, 2)' : >color = black : >w = in_w : >h = in_h : >thickness = fill > , > drawbox=enable='between(t, 339, 342)' : >color = black : >w = in_w : >h = in_h : >thickness = fill >" \ >-acodec copy\ >-vcodec libx264 \ >-crf23 \ >speechClean2.mp4 With the help of this mailing list I changed it to: ffmpeg -y \ -ss 00:19:49\ -i 2021-03-25ToastmastersClubAvond.mp4 \ -to 442 \ -vf " crop = 1440:1080:240:0 , drawbox=enable='bitor(between(t, 0, 2),between(t, 339, 342))' : color = black : w = in_w : h = in_h : thickness = fill " \ -acodec copy\ -vcodec libx264 \ -preset veryfast\ -crf28 \ speechClean3.mp4 The input quality is probably poor, that is why I switched to crf 28. I do not see a difference in quality. I use veryfast because that probably gives (counter-intuitively) the smallest size. > The reason I do -to in the output is that in this way the metadata > concerning the video length is less out of whack. > > I was wondering if this is a good way, or that it could be done > better? > Also, beside the timestamps the parameters for drawbox are the same. > Is there a way that I do not have to repeat them? > > I started the crf with 16, then 20 and lastly 23. > > The input file has: > Stream #0:1(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, > 1920x1080, 2070 kb/s, 25 fps, 25 tbr, 30k tbn, 60k tbc (default) > > With crf 16 I get: > Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, > 1440x1080, 5541 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default) > > With crf 20 I get: > Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, > 1440x1080, 3538 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default) > > And with crf 23 I get: > Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, > 1440x1080, 2444 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default) With crf 28 and preset veryfast I get: Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1440x1080, 1056 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default) When I have better quality video I should maybe change crf back to 23. -- Cecil Westerhof Senior Software Engineer LinkedIn: http://www.linkedin.com/in/cecilwesterhof ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-user] Cut part of a video, crop it and blackout parts of it
Am 05.04.2021 um 11:58 schrieb Cecil Westerhof via ffmpeg-user: Michael Koch writes: Am 05.04.2021 um 01:48 schrieb Cecil Westerhof via ffmpeg-user: I have to cut out a part of a video, crop it and blackout two parts. I do this with: ffmpeg -y \ -ss 00:19:49\ -i 2021-03-25ToastmastersClubAvond.mp4 \ -to 442 \ -vf " crop = 1440:1080:240:0 , drawbox=enable='between(t, 0, 2)' : color = black : w = in_w : h = in_h : thickness = fill , drawbox=enable='between(t, 339, 342)' : color = black : w = in_w : h = in_h : thickness = fill " \ -acodec copy\ -vcodec libx264 \ -crf23 \ speechClean2.mp4 The reason I do -to in the output is that in this way the metadata concerning the video length is less out of whack. I was wondering if this is a good way, or that it could be done better? Also, beside the timestamps the parameters for drawbox are the same. Is there a way that I do not have to repeat them? drawbox=enable='bitor(between(t, 0, 2),between(t, 339, 342))' Works like a charm. Strange thing is that it seems to be much faster. About 20%. To much to be because of different load I think. But I am not complaining. ;-) If you want to cover the whole frame size, you could also use this (for 50% gray): eq=enable='bitor(between(t, 0, 2),between(t, 339, 342))':contrast=0 or add :brightness=-0.5 if you want black. It might be faster than drawbox. Michael ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-user] Cut part of a video, crop it and blackout parts of it
Cecil Westerhof via ffmpeg-user writes: > Nicolas George writes: > >> Carl Eugen Hoyos (12021-04-05): >>> There is a fundamental misunderstanding: >>> You decide how much quality you want to preserve, x264 decides how >>> much bitrate is needed to reach that quality. >> >> You also decide how much computing power you want to spend on it, which >> Cecil neglected to do. More computing power usually means lower bitrate >> for same quality. The keyword is "preset". > > Yes, that was not smart. > > The funny thing about that is that years ago I have played with that. > My very strange finding was that I could best use veryfast. It was > faster and created smaller files. But that is many years ago, so maybe > that is not true anymore. Until two years ago it was still the case: https://write.corbpie.com/ffmpeg-preset-comparison-x264-2019-encode-speed-and-file-size/ I ran it with veryfast. It took about half the time and kb/s was 2164 instead of 2444. Better, but still about 40% higher as I would expect. -- Cecil Westerhof Senior Software Engineer LinkedIn: http://www.linkedin.com/in/cecilwesterhof ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-user] Cut part of a video, crop it and blackout parts of it
Michael Koch writes: > Am 05.04.2021 um 01:48 schrieb Cecil Westerhof via ffmpeg-user: >> I have to cut out a part of a video, crop it and blackout two parts. >> I do this with: >> ffmpeg -y \ >> -ss 00:19:49\ >> -i 2021-03-25ToastmastersClubAvond.mp4 \ >> -to 442 \ >> -vf " >> crop = 1440:1080:240:0 >> , >> drawbox=enable='between(t, 0, 2)' : >> color = black : >> w = in_w : >> h = in_h : >> thickness = fill >> , >> drawbox=enable='between(t, 339, 342)' : >> color = black : >> w = in_w : >> h = in_h : >> thickness = fill >> " \ >> -acodec copy\ >> -vcodec libx264 \ >> -crf23 \ >> speechClean2.mp4 >> >> The reason I do -to in the output is that in this way the metadata >> concerning the video length is less out of whack. >> >> I was wondering if this is a good way, or that it could be done >> better? >> Also, beside the timestamps the parameters for drawbox are the same. >> Is there a way that I do not have to repeat them? > > drawbox=enable='bitor(between(t, 0, 2),between(t, 339, 342))' Works like a charm. Strange thing is that it seems to be much faster. About 20%. To much to be because of different load I think. But I am not complaining. ;-) -- Cecil Westerhof Senior Software Engineer LinkedIn: http://www.linkedin.com/in/cecilwesterhof ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-user] Cut part of a video, crop it and blackout parts of it
Nicolas George writes: > Carl Eugen Hoyos (12021-04-05): >> There is a fundamental misunderstanding: >> You decide how much quality you want to preserve, x264 decides how >> much bitrate is needed to reach that quality. > > You also decide how much computing power you want to spend on it, which > Cecil neglected to do. More computing power usually means lower bitrate > for same quality. The keyword is "preset". Yes, that was not smart. The funny thing about that is that years ago I have played with that. My very strange finding was that I could best use veryfast. It was faster and created smaller files. But that is many years ago, so maybe that is not true anymore. Time to play with preset again. -- Cecil Westerhof Senior Software Engineer LinkedIn: http://www.linkedin.com/in/cecilwesterhof ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-user] Cut part of a video, crop it and blackout parts of it
Carl Eugen Hoyos writes: >> Am 05.04.2021 um 01:48 schrieb Cecil Westerhof via ffmpeg-user >> : >> >> I have to cut out a part of a video, crop it and blackout two parts. >> I do this with: >>ffmpeg -y \ >> -ss 00:19:49\ >> -i 2021-03-25ToastmastersClubAvond.mp4 \ >> -to 442 \ >> -vf " >>crop = 1440:1080:240:0 >>, >>drawbox=enable='between(t, 0, 2)' : >> color = black : >> w = in_w : >> h = in_h : >> thickness = fill >>, >>drawbox=enable='between(t, 339, 342)' : >> color = black : >> w = in_w : >> h = in_h : >> thickness = fill >> " \ >> -acodec copy\ >> -vcodec libx264 \ >> -crf23 \ >> speechClean2.mp4 >> >> The reason I do -to in the output is that in this way the metadata >> concerning the video length is less out of whack. >> >> I was wondering if this is a good way, or that it could be done >> better? > >> Also, beside the timestamps the parameters for drawbox are the same. >> Is there a way that I do not have to repeat them? > > I suspect there is an „Or“ parameter for „enable“. > >> >> I started the crf with 16, then 20 and lastly 23. >> >> The input file has: >>Stream #0:1(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, >> 1920x1080, 2070 kb/s, 25 fps, 25 tbr, 30k tbn, 60k tbc (default) >> >> With crf 16 I get: >>Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, >> 1440x1080, 5541 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default) >> >> With crf 20 I get: >>Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, >> 1440x1080, 3538 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default) >> >> And with crf 23 I get: >>Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, >> 1440x1080, 2444 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default) >> >> So to me it seems that the crf value is still to high. > > You mean still too low? Yes, bitrate is to high, so the crf value is to low. Silly me. ;-) >> Is there a way >> to use the kb/s to calculate the crf value to use? > > There is a fundamental misunderstanding: > You decide how much quality you want to preserve, x264 decides how much > bitrate is needed to reach that quality. (This is true for the general > case where you want to control the output quality and are therefore > using the crf option.) > If you really have bitrate constraints, use two-pass encoding > instead of the crf option. I do not really have a bitrate constraint, but I would think a higher bitrate as the input bitrate would be a waste. Because the crop removes about a quarter I would think that a bitrate higher as 1500 would be a waste. > I suspect the reason for the high bitrate of the output file is the low > quality of the input file but this is not really relevant, just a > (possible) explanation. One (unlikely) alternative is that your original > h264 encoder is much better than x264. That is what I mean: if the quality of the input is low, then there is no use for going for a high(er) quality for the output. -- Cecil Westerhof Senior Software Engineer LinkedIn: http://www.linkedin.com/in/cecilwesterhof ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-user] Cut part of a video, crop it and blackout parts of it
Carl Eugen Hoyos (12021-04-05): > There is a fundamental misunderstanding: > You decide how much quality you want to preserve, x264 decides how > much bitrate is needed to reach that quality. You also decide how much computing power you want to spend on it, which Cecil neglected to do. More computing power usually means lower bitrate for same quality. The keyword is "preset". Regards, -- Nicolas George signature.asc Description: PGP signature ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-user] Cut part of a video, crop it and blackout parts of it
Am 05.04.2021 um 01:48 schrieb Cecil Westerhof via ffmpeg-user: I have to cut out a part of a video, crop it and blackout two parts. I do this with: ffmpeg -y \ -ss 00:19:49\ -i 2021-03-25ToastmastersClubAvond.mp4 \ -to 442 \ -vf " crop = 1440:1080:240:0 , drawbox=enable='between(t, 0, 2)' : color = black : w = in_w : h = in_h : thickness = fill , drawbox=enable='between(t, 339, 342)' : color = black : w = in_w : h = in_h : thickness = fill " \ -acodec copy\ -vcodec libx264 \ -crf23 \ speechClean2.mp4 The reason I do -to in the output is that in this way the metadata concerning the video length is less out of whack. I was wondering if this is a good way, or that it could be done better? Also, beside the timestamps the parameters for drawbox are the same. Is there a way that I do not have to repeat them? drawbox=enable='bitor(between(t, 0, 2),between(t, 339, 342))' Michael ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-user] Cut part of a video, crop it and blackout parts of it
> Am 05.04.2021 um 01:48 schrieb Cecil Westerhof via ffmpeg-user > : > > I have to cut out a part of a video, crop it and blackout two parts. > I do this with: >ffmpeg -y \ > -ss 00:19:49\ > -i 2021-03-25ToastmastersClubAvond.mp4 \ > -to 442 \ > -vf " >crop = 1440:1080:240:0 >, >drawbox=enable='between(t, 0, 2)' : > color = black : > w = in_w : > h = in_h : > thickness = fill >, >drawbox=enable='between(t, 339, 342)' : > color = black : > w = in_w : > h = in_h : > thickness = fill > " \ > -acodec copy\ > -vcodec libx264 \ > -crf23 \ > speechClean2.mp4 > > The reason I do -to in the output is that in this way the metadata > concerning the video length is less out of whack. > > I was wondering if this is a good way, or that it could be done > better? > Also, beside the timestamps the parameters for drawbox are the same. > Is there a way that I do not have to repeat them? I suspect there is an „Or“ parameter for „enable“. > > I started the crf with 16, then 20 and lastly 23. > > The input file has: >Stream #0:1(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, > 1920x1080, 2070 kb/s, 25 fps, 25 tbr, 30k tbn, 60k tbc (default) > > With crf 16 I get: >Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, > 1440x1080, 5541 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default) > > With crf 20 I get: >Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, > 1440x1080, 3538 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default) > > And with crf 23 I get: >Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, > 1440x1080, 2444 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default) > > So to me it seems that the crf value is still to high. You mean still too low? > Is there a way > to use the kb/s to calculate the crf value to use? There is a fundamental misunderstanding: You decide how much quality you want to preserve, x264 decides how much bitrate is needed to reach that quality. (This is true for the general case where you want to control the output quality and are therefore using the crf option.) If you really have bitrate constraints, use two-pass encoding instead of the crf option. I suspect the reason for the high bitrate of the output file is the low quality of the input file but this is not really relevant, just a (possible) explanation. One (unlikely) alternative is that your original h264 encoder is much better than x264. Carl Eugen ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-user] Using Homebrew to install FFmpeg, But having wired problems.
> Am 05.04.2021 um 04:39 schrieb Kosei Seki <1446513973wh...@gmail.com>: > > (base) XXX-MacBook-Air ~ % brew install ffmpeg --HEAD You will have to ask elsewhere (we are not brew) if you don’t like the links on our download page: http://ffmpeg.org/download.html Carl Eugen ___ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
