September 2013 - ffmpeg-user - lists.ffmpeg.org

Syncing clips based on audio waveform?
by Arthur Wait 05 Oct '17

05 Oct '17

Hi all, This is coming from out of left field I imagine, but I'm wondering if anyone knows of a filter (or chain of filters) which would allow me to align/sync two video clips based on matches in their audio waveforms. I'm shooting events with multiple cameras and would like to either trim the clips to a precise, matching starting frame or generate a metadata "offset" marker indicating how far off one clip is from the other in time. Then I can trim the clips to match. Is this possible in ffmpeg (or anywhere else for that matter!)? Thanks very much! Art

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Compiling FFMPEG with ffplay support
by Stas Oskin 14 Jun '17

14 Jun '17

Hi. Did the compilation parameters changed in recent FFMPEG version? Configuring the FFMPEG like this: ./configure --prefix=/usr --enable-pthreads Does not produce ffplay anymore. I tried to add --enable-ffplay, without any result. Any idea what I'm missing? Thanks.

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How do I encode DVB Subtitles?
by Wagner Patriota 02 May '17

02 May '17

*QUESTION 1:* How do I add a STR file to a MPEG-TS file with the "DVB subtitle codec"? If so, could you give me a sample command line? Thank. I am trying: ffmpeg -i video.ts *-i subtitle.srt* -vcodec copy -acodec copy *-scodec dvbsub* output.ts The stream is created because I can see it with MediaInfo, but the subtitles don't appear! *QUESTION 2:* How do I use the command *slang*? I try to use it, but ffmpeg says the command doesn't exist. Thank you.

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How to use global_header, fflags, rtpflags parameter.
by Ly Tran Cong 06 Dec '16

06 Dec '16

Hello, Can anyone tell me how to use flags +global_header, fflags +latm, rtpflags +latm Which parameter using with video encode and which parameter using with audio encode. Thanks -- Regards, Tran Ly Vega Corporation 98 Hoang Quoc Viet Str, Hanoi, Vietnam Tel: 84 4 755 4190 Fax: 84 4 755 4190 Mobile: 84 91 487 1115 www.vega.com.vn; www.clip.vn; www.chacha.vn; www.ringring.vn

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Flip in sws_scale
by romulo.fernandes＠gmail.com 11 Mar '16

11 Mar '16

Hello, I'm using libswscale to scale and convert pixel format from frames that I capture from the screen. In my windows build the frames that I capture are in DIB format. I'm using FFMPEG SVN rev 16437. Calling sws_scale normally I get the image correctly, except that it's vertically flipped. If I change the srcSliceY from 0 to srcHeight and srcSliceH from srcHeight to 0, I get a grey image (with correct dimensions). If I keep the srcSliceY in 0 and change srcSliceH from srcHeight to -srcHeight, I also get that grey image. Is there a way to make sws_scale flip the image for me ?

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Howto compile ffplay.c in seperate directory with my own svn-version of ffmpeg
by tps＠netmaster.dk 24 Feb '16

24 Feb '16

Dear All I have compiled svn-version of ffmpeg. I only do configure and make. I do not do make install because I don't want this svn-version of ffmpeg to overwrite the 'official' Ubuntu version of ffpeg that is also on the host. Now I want to compile my own version of ffplay.c so I create a directory ffplay at the same level as the svn ffmpeg-directory. I copy ffplay.c from ffmpeg to ffplay. Now what gcc options should I use to compile ffplay.c? I tried with this but got tons of errors: gcc -o ffplay ffplay.c -I../ffmpeg -L../ffmpeg/libavcodec -L../ffmpeg/libavformt -L../ffmpeg/libswscale -L../ffmpeg/libavutil -lavcodec -lavformat -lswscale -lavutil -lmp3lame -lx264 `sdl-config --cflags --libs` I note that when I do the make in the svn ffmpeg-directory there are a lot of options on the gcc command. I hardly know any of the options. Thanks in advance

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timestamp calculation
by Chau Pham 25 Jun '15

25 Jun '15

Hi Everybody, Suppose that I know AVPacket element: pts, dts, duration How could I calculate the timestamp (hh:mm:ss:MMM)? Thank You,Chau Pham.

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Problem in FFMPEG 1.1
by Simone Cercignani 14 Apr '15

14 Apr '15

Hi, I am trying to compile ffmpeg 1.1 with: ./configure --toolchain=msvc I have followed the instruction at: https://ffmpeg.org/platform.html#Microsoft-Visual-C_002b_002b but after that command: Simone@Simone-PC /c/Jobs/ffmpeg-1.1 $ ./configure toolchain=msvc c99wrap cl is unable to create an executable file. If c99wrap cl is a cross-compiler, use the --enable-cross-compile option. Only do this if you know what cross compiling means. C compiler test failed. If you think configure made a mistake, make sure you are using the latest version from Git. If the latest version fails, report the problem to the ffmpeg-user(a)ffmpeg.org mailing list or IRC #ffmpeg on irc.freenode.net. Include the log file "config.log" produced by configure as this will help solving the problem. Simone@Simone-PC /c/Jobs/ffmpeg-1.1 $ in attachment the "config.log" file.... Thanks in advance Simone

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Converting MPEG-TS to MKV with hard coded subtitles produces error message
by Stuart 09 Apr '15

09 Apr '15

Hello, I want to convert an MPEG-TS from a Humax PVR to a MKV with H.264 encoded video with hard coded DVB subtitles. Unfortunately, having downloaded a build from ffmpeg.zeranoe.com, instead of hard coded subtitles I am getting "sub2video: rectangle overflowing" messages. I've tweaked ffmpeg.c to display the parameters causing the message and built a cut down ffmpeg. (I have built a toolchain using Zeranoe's build script and built libogg, libvorbis, libx264 and pthreads-win32 from source). The message is output because the video stream is 704x576 but the subtitle rectangles are 720 wide. If I tweak function sub2video_prepare in ffmpeg_filter.c to hard code the canvas width and height to be 720 and 576 respectively then I can produce an MKV with hard coded DVB subtitles with the command: ffmpeg -i in.TS -filter_complex "[0:v]pad=720:576[main];[main][0:s]overlay" -sn out.MKV I've tried cropping the subtitle stream before overlaying but still get the "sub2video: rectangle overflowing" messages with the Zeranoe build. I've also tried scaling the video stream and padding the video stream. I think the canvas size is assigned equal to the video stream size before applying the filters. Hence, scaling or padding the video stream doesn't increase the canvas size to match the subtitle rectangle dimensions. Is there a filter sequence that would accommodate the subtitle rectangle dimensions being larger than the video stream dimensions? Or does the sub2video "hack" not cater for this situation? Many thanks, Stu

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Decode to BGR24 avi
by Timo Stjernberg 02 Apr '15

02 Apr '15

Hello. I am returning this issue back via the actual mailing list, since posting via nabble.com doesn't seem to work right. Refer to http://ffmpeg-users.933282.n4.nabble.com/Decode-to-BGR24-raw-AVI-td4653855.… the original thread. There seems to be a disagreement between FFmpeg and VirtualDub of what uncompressed bgr24 raw avi really is. I can tell this already by looking at file sizes that they produce from the same video but PSNR & other metrics tell me they're definitely not the same video. I have done extensive testing on different videos with ffmpeg and so I decided to set this test up for you guys to figure out what is going south on bgr24 raw avi's. All example video files are accessible at http://videotimo.fi/ffmpeg/ TEST PHASE 1: We start with a raw original avi that has been built from PNG frames with VirtualDub (sintel_raw_original.avi). We make a rawvideo -pix_fmt bgr24 copy of it with ffmpeg to find out that even when there should be no difference between input and output, the files are not the same in size. (sintel_ffmpeg_raw2raw.avi) Console output: ffmpeg -i G:\Testivideot\sintel_raw_original.avi -vcodec rawvideo -pix_fmt bgr24 sintel_ffmpeg_raw2raw.avi: ffmpeg version N-47062-g26c531c Copyright (c) 2000-2012 the FFmpeg developers built on Nov 25 2012 12:21:26 with gcc 4.7.2 (GCC) configuration: --enable-gpl --enable-version3 --disable-pthreads --enable-runt ime-cpudetect --enable-avisynth --enable-bzlib --enable-frei0r --enable-libass - -enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libfreetype --enab le-libgsm --enable-libmp3lame --enable-libnut --enable-libopenjpeg --enable-libo pus --enable-librtmp --enable-libschroedinger --enable-libspeex --enable-libtheo ra --enable-libutvideo --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-li bvorbis --enable-libvpx --enable-libx264 --enable-libxavs --enable-libxvid --ena ble-zlib libavutil 52. 9.100 / 52. 9.100 libavcodec 54. 77.100 / 54. 77.100 libavformat 54. 37.100 / 54. 37.100 libavdevice 54. 3.100 / 54. 3.100 libavfilter 3. 23.102 / 3. 23.102 libswscale 2. 1.102 / 2. 1.102 libswresample 0. 17.101 / 0. 17.101 libpostproc 52. 2.100 / 52. 2.100 Input #0, avi, from 'G:\Testivideot\sintel_raw_original.avi': Duration: 00:00:01.21, start: 0.000000, bitrate: 234514 kb/s Stream #0:0: Video: rawvideo, bgr24, 848x480, 24 tbr, 24 tbn, 24 tbc Output #0, avi, to 'd:\sintel_ffmpeg_raw2raw.avi': Metadata: ISFT : Lavf54.37.100 Stream #0:0: Video: rawvideo, bgr24, 848x480, q=2-31, 200 kb/s, 24 tbn, 24 t bc Stream mapping: Stream #0:0 -> #0:0 (rawvideo -> rawvideo) Press [q] to stop, [?] for help frame= 21 fps=0.0 q=0.0 size= 25048kB time=00:00:00.87 bitrate=234508.5kbits frame= 29 fps=0.0 q=0.0 Lsize= 34589kB time=00:00:01.20 bitrate=234497.3kbit s/s video:34582kB audio:0kB subtitle:0 global headers:0kB muxing overhead 0.018011% ---------------------------------------------------------------------------------- TEST PHASE 2: We encode the raw original to mpeg2 (sintel_ffmpeg_raw2mpeg2.avi). The encode goes smoothly. Console output: ffmpeg -i sintel_raw_original.avi -vcodec mpeg2video -b:v 2000k sintel_ffmpeg_raw2mpeg2.avi: ffmpeg version N-47062-g26c531c Copyright (c) 2000-2012 the FFmpeg developers built on Nov 25 2012 12:21:26 with gcc 4.7.2 (GCC) configuration: --enable-gpl --enable-version3 --disable-pthreads --enable-runt ime-cpudetect --enable-avisynth --enable-bzlib --enable-frei0r --enable-libass - -enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libfreetype --enab le-libgsm --enable-libmp3lame --enable-libnut --enable-libopenjpeg --enable-libo pus --enable-librtmp --enable-libschroedinger --enable-libspeex --enable-libtheo ra --enable-libutvideo --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-li bvorbis --enable-libvpx --enable-libx264 --enable-libxavs --enable-libxvid --ena ble-zlib libavutil 52. 9.100 / 52. 9.100 libavcodec 54. 77.100 / 54. 77.100 libavformat 54. 37.100 / 54. 37.100 libavdevice 54. 3.100 / 54. 3.100 libavfilter 3. 23.102 / 3. 23.102 libswscale 2. 1.102 / 2. 1.102 libswresample 0. 17.101 / 0. 17.101 libpostproc 52. 2.100 / 52. 2.100 Input #0, avi, from 'G:\Testivideot\sintel_raw_original.avi': Duration: 00:00:01.21, start: 0.000000, bitrate: 234514 kb/s Stream #0:0: Video: rawvideo, bgr24, 848x480, 24 tbr, 24 tbn, 24 tbc Output #0, avi, to 'd:\sintel_ffmpeg_raw2mpeg2.avi': Metadata: ISFT : Lavf54.37.100 Stream #0:0: Video: mpeg2video (mpg2 / 0x3267706D), yuv420p, 848x480, q=2-31 , 2000 kb/s, 24 tbn, 24 tbc Stream mapping: Stream #0:0 -> #0:0 (rawvideo -> mpeg2video) Press [q] to stop, [?] for help frame= 19 fps=0.0 q=4.0 size= 302kB time=00:00:00.70 bitrate=3494.3kbits/s frame= 29 fps=0.0 q=3.5 Lsize= 408kB time=00:00:01.16 bitrate=2865.0kbits/ s video:402kB audio:0kB subtitle:0 global headers:0kB muxing overhead 1.554130% ------------------------------------------------------------------------------ TEST PHASE 3: We decode the mpeg2 video back to bgr24 raw avi (sintel_ffmpeg_mpeg2toRAW.avi). The result is not at all what I would expect. The decoded video has one frame more than the original. Therefore if I compare the original and the decoded video for PSNR or MAE, the calculations don't match at all. Only if I strip the first frame from the decoded avi, the calculations seem valid. Console output: ffmpeg -i D:\sintel_ffmpeg_raw2mpeg2.avi -vcodec rawvideo -pix_fmt bgr24 d:\sintel_ffmpeg_mpeg2toRAW.avi ffmpeg version N-47062-g26c531c Copyright (c) 2000-2012 the FFmpeg developers built on Nov 25 2012 12:21:26 with gcc 4.7.2 (GCC) configuration: --enable-gpl --enable-version3 --disable-pthreads --enable-runt ime-cpudetect --enable-avisynth --enable-bzlib --enable-frei0r --enable-libass - -enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libfreetype --enab le-libgsm --enable-libmp3lame --enable-libnut --enable-libopenjpeg --enable-libo pus --enable-librtmp --enable-libschroedinger --enable-libspeex --enable-libtheo ra --enable-libutvideo --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-li bvorbis --enable-libvpx --enable-libx264 --enable-libxavs --enable-libxvid --ena ble-zlib libavutil 52. 9.100 / 52. 9.100 libavcodec 54. 77.100 / 54. 77.100 libavformat 54. 37.100 / 54. 37.100 libavdevice 54. 3.100 / 54. 3.100 libavfilter 3. 23.102 / 3. 23.102 libswscale 2. 1.102 / 2. 1.102 libswresample 0. 17.101 / 0. 17.101 libpostproc 52. 2.100 / 52. 2.100 Input #0, avi, from 'D:\sintel_ffmpeg_raw2mpeg2.avi': Metadata: encoder : Lavf54.37.100 Duration: 00:00:01.21, start: 0.000000, bitrate: 2766 kb/s Stream #0:0: Video: mpeg2video (Main) (mpg2 / 0x3267706D), yuv420p, 848x480 [SAR 1:1 DAR 53:30], 24 fps, 24 tbr, 24 tbn, 48 tbc Output #0, avi, to 'd:\sintel_ffmpeg_mpeg2toRAW.avi': Metadata: ISFT : Lavf54.37.100 Stream #0:0: Video: rawvideo, bgr24, 848x480 [SAR 1:1 DAR 53:30], q=2-31, 20 0 kb/s, 24 tbn, 24 tbc Stream mapping: Stream #0:0 -> #0:0 (mpeg2video -> rawvideo) Press [q] to stop, [?] for help frame= 29 fps=0.0 q=0.0 Lsize= 34589kB time=00:00:01.25 bitrate=226681.3kbit s/s video:34582kB audio:0kB subtitle:0 global headers:0kB muxing overhead 0.018293% --------------------------------------------------------------------------------- This extraneous frame does seem to appear at least with VC-1 and mpeg2 encode/decode process. Still, something is done very differently on all bgr24 raw avi decodes because I still have to run all the raw avi decodes through VirtualDub after ffmpeg before feeding the test videos to the PSNR calculator. Additionally, Microsoft Expression Encoder 4 doesn't seem to understand the raw avi produced by ffmpeg at all. Anybody had any similar incidents? Anybody that can clarify any of this? What am I doing wrong?

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