December 2009 - ffmpeg-user - lists.ffmpeg.org

.m4a to .flv - image/video fails
by nreddig＠ptd.net 31 Mar '12

31 Mar '12

Hi all, I have greatly appreciated the information I have already gleaned from reading this forum. However I still can not solve my current problem. I am trying to convert from .m4a to .flv. These are podcast files (.m4a) built in garage band. Pictures were added as well and we would like to use this format to create weekly announcements because Garage Band is so easy for our non-technically oriented staff. Using ffmpeg the audio converts just fine but the "video" is not right. I guess it's because these files include chapter data not actual video. However when I convert it to any format the images fly through at different rates, then it seems to get stuck on a picture in the middle. The format I would like to convert to is flash so that I can easy display multiple announcement files using a flash player. I can convert .mov to .flv no problem. Converting .m4a to .mov and then .flv doesn't produce any better results. Here are the before and after files: http://www.warwicksd.org/warwick.m4a http://www.warwicksd.org/output.flv I used the following to get my conversion: ffmpeg -i warwick.m4a -b 300k -r 12 -s 300x300 -ar 22050 -y -ab 96k output.flv FFmpeg version SVN-rUNKNOWN, Copyright (c) 2000-2007 Fabrice Bellard, et al. configuration: --enable-gpl --enable-libfaac --enable-libfaad --enable- libmp3lame --disable-vhook --enable-shared libavutil version: 49.5.0 libavcodec version: 51.44.0 libavformat version: 51.14.0 built on Oct 22 2007 15:31:25, gcc: 3.3 20030304 (Apple Computer, Inc. build 1640) Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'warwick.m4a': Duration: 00:00:55.9, start: 0.000000, bitrate: 100 kb/s Stream #0.0(eng): Audio: mpeg4aac, 44100 Hz, stereo Stream #0.1(eng): Video: mjpeg, yuvj420p, 300x300, 44100.00 fps(r) Stream #0.2(eng): Data: tx3g / 0x67337874 Stream #0.3(eng): Data: text / 0x74786574 Output #0, flv, to 'output.flv': Stream #0.0(eng): Video: flv, yuv420p, 300x300, q=2-31, 300 kb/s, 12.00 fps (c) Stream #0.1(eng): Audio: libmp3lame, 22050 Hz, stereo, 96 kb/s Stream mapping: Stream #0.1 -> #0.0 Stream #0.0 -> #0.1 Press [q] to stop encoding frame= 83 fps= 21 q=2.0 Lsize= 1099kB time=6.9 bitrate=1301.6kbits/s video:70kB audio:657kB global headers:0kB muxing overhead 51.296550% .mov files convert nicely to .flv but these .m4as are just not working. Our current staff is very eager to use these Garage Band files to communicate announcements. I have been so desperate to get this particular file type to convert that I have been experimenting with grabbing the frames every 5 secs. and then rebuilding the images into video. This produces strange results and seems to be more programming then should be necessary. Thanks in advanced for any solutions you can provide. Nancy Reddig Web Programmer Warwick SD

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Scene detection
by foripepe＠yahoo.com 01 Mar '12

01 Mar '12

Hi, I would like to generate images from videos at every scene changes. My present solution is: - ffmpeg -i source_video -r 25 -an -vcodec mjpeg destination_video.avi - lav2yuv -S list.el destination_video.avi It generates a scene list text file with time codes that I use later to creating images. I was wondering maybe there is an easier solution. I have browsed the net to get a better solution (ffmpeg, sc_threshold etc.), but I couldn't find any other just my present lav2yus solution. Is it possible to use ffmpeg to create images on scene changes? Or is it possible to use ffmpeg to create a text file with the time codes of scene changes? If you have any idea, I would be very happy. Thanks in advance.

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Can ffmpeg extract clips from ogg video files?
by vfclists＠googlemail.com 23 Jan '12

23 Jan '12

I am trying to extract clips from an ogg video generated from vlc 1.0 and ffmpeg always crashes when trying to do so. Is ffmpeg capable of doing that? -- Frank Church ======================= <a href="http://devblog.brahmancreations.com">devblog.brahmancreations.com</a>

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Frame/gop accurate video splitting (fps, gop, length known)
by abodera＠gmail.com 22 Dec '11

22 Dec '11

Hey there! A simple use case: 1) a sample mp4 file of 23.98 tbr, 264 + aac, 1:51.27 in length 2) the file (lotr trailer) encoded with: ./ffmpeg -i ./lordoftherings_h640_ml.mov -vcodec libx264 -g 50 ./lord.mp4 3) we want to split it in 3 parts: 30s, 10s and the rest of the stream Chunks we want to have: 1) ~30s (00:00:00 - 00:00:30) 2) ~10s (00:00:30 - 00:00:40) 3) ~71s (00:00:40 - 00:01:51) File info: Duration: 00:01:51.27, start: 0.000000, bitrate: 256 kb/s Stream #0.0(eng): Video: h264, yuv420p, 640x272, 192 kb/s, 47.90 fps, 23.98 tbr, 24k tbn, 47.95 tbc Stream #0.1(eng): Audio: aac, 48000 Hz, stereo, s16, 58 kb/s The only tools right now are -vframes, -ss and -t. Frame-accurate seeking is missing/broken (?). Below is my approach. a) chunk 1 is 30s, so with 23.98 fps that gives 719.5 frames. b) Because it's gop 50 we round down to 700 frames = 29.1909925 seconds from start c) Chunk 1 extraction: "-vframes 699" d) Chunk 2 starts from frames 700 and ends in 10s = 239.8 frames ~ 250 frames (gop 50) e) Chunk 2 extraction: "-ss 29.1909925 -vframes 250" f) Chunk 3 starts at 40s = 959.2th frames (23.98 fps). Rounding down to 50 gives us 950th frame g) 950th frame is at aproximately 39.61635 sec. g) Chunk 3 extraction: "-ss 39.61635" Of course I wouldn't be bothering the community if it worked properly :-) The chunks are off by many seconds, lengths are off. Please assist - what am I doing wrong? Is there any more elegant way to do that? Also: a simpler case that I thought would "just work" - split the stream in two: ./ffmpeg -y -ss -t 30 -i ./lord.mp4 -vcodec copy -acodec copy lord-chunk1.mp4 ./ffmpeg -y -ss 00:00:30 -i ./lord.mp4 -vcodec copy -acodec copy lord-chunk2.mp4 It doesn't work! This will also end badly with two arbitrary length chunks with seek times that make little sense. How is it done properly? Thanks! Arthur. ps: FFmpeg version SVN-r20880 -- __ /.)\ +48 695 600 936 \(./ abodera at gmail.com

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milliseconds to mpeg-ts pts/dts
by steuer＠unixsystems.de 07 Sep '11

07 Sep '11

guys, i try to create an mpegts file from H.264 and ACC raw frames that i receive from a network connection. I create AVPacket structures, set data, size, pts and dts etc. manually. For the stream that I receive, PTS and DTS seem to be equal, so I just calculate the packet pts and dts with incoming pts / 1000.0 * 90000.0 I do that for audio and video. Unfortunately that seems to be wrong as ffmpeg states "dts < pcr, TS is invalid" after a couple of seconds. I seems that the timestamps run out of sync with the internal pcr reference clock. What would be the correct way to calculate the pts and dts of the mpegts stream? Thanks alot for your help! Cheers, Heri

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Hint tracks support for MP4
by stas.oskin＠gmail.com 16 Aug '11

16 Aug '11

Hi. Any idea if FFMPEG supports / will be supporting adding hint tracks to MP4 files for RTSP streaming? Regards.

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Reading RTSP from Axis cameras via FFMPEG
by stas.oskin＠gmail.com 10 Jun '11

10 Jun '11

Hi. I'm trying to read video from Axis camera via ffmpeg and ffplay. The use link goes like this: rtsp://192.168.253.201:554/mpeg4/media.amp The video starts fine, but then immediately breaks to parts. ffmpeg/ffplay start to throw the following errors: [mpeg4 @ 0x1a350400]concealing 661 DC, 661 AC, 661 MV errors [mpeg4 @ 0x1a350400]slice end not reached but screenspace end (44419 left 6CC8BD, score= -262) [mpeg4 @ 0x1a350400]concealing 690 DC, 690 AC, 690 MV errors [mpeg4 @ 0x1a350400]slice end not reached but screenspace end (12453 left 7E1653, score= -263) [mpeg4 @ 0x1a350400]concealing 690 DC, 690 AC, 690 MV errors [mpeg4 @ 0x1a350400]1. marker bit missing in 3. esc [mpeg4 @ 0x1a350400]Error at MB: 206 [mpeg4 @ 0x1a350400]concealing 539 DC, 539 AC, 539 MV errors [mpeg4 @ 0x1a350400]slice end not reached but screenspace end (11108 left 7091E5, score= -268) [mpeg4 @ 0x1a350400]concealing 690 DC, 690 AC, 690 MV errors [mpeg4 @ 0x1a350400]I cbpy damaged at 18 9 [mpeg4 @ 0x1a350400]Error at MB: 297 [mpeg4 @ 0x1a350400]concealing 451 DC, 451 AC, 451 MV errors [mpeg4 @ 0x1a350400]slice end not reached but screenspace end (11107 left 6CF4B6, score= -275) [mpeg4 @ 0x1a350400]concealing 690 DC, 690 AC, 690 MV errors [mpeg4 @ 0x1a350400]slice end not reached but screenspace end (11110 left 7C5C0C, score= -279) [mpeg4 @ 0x1a350400]concealing 690 DC, 690 AC, 690 MV errors VLC, when connecting to same link, works just fine. Any idea what happens? Thanks!

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m2ts to DNxHD convert
by luismanolo＠gmail.com 24 Apr '11

24 Apr '11

Hello. Sorry about my english. I`m a new user of ffmpeg, and I have a sony hd camera. And I want to convert the MTS files of my camera to the codec of Apple Pro Res called dnxhd. I know that this codecs are supported for ffmpeg but I don`t know command to convert the video. I`m a ubuntu linux user. And I use cinelerra to edit the files. Many Thanks. -- http://vimeo.com/luismanolo http://delasonsierra.blogspot.com http://www.logrobomberos.com

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Assertion and crash in MKV
by dennis.volodomanov＠conceiva.com 25 Oct '10

25 Oct '10

Hello, I've got the following error - FFmpeg version git-6a1265c, Copyright (c) 2000-2009 Fabrice Bellard, et al. configuration: --enable-gpl --enable-shared --disable-static --enable-memalign-hack --enable-libmp3lame --extra-cflags=-I/c/msys/local/include --extra-ldflags=-L/c/msys/local/lib --enable-swscale --extra-cflags=-fno-common libavutil 49.12. 0 / 49.12. 0 libavcodec 52.10. 0 / 52.10. 0 libavformat 52.23. 1 / 52.23. 1 libavdevice 52. 1. 0 / 52. 1. 0 libswscale 0. 6. 1 / 0. 6. 1 built on Jan 8 2009 11:01:43, gcc: 4.2.1-sjlj (mingw32-2) Assertion failed: s->chapters[i]->start <= s->chapters[i+1]->start, file libavformat/utils.c, line 1968 This application has requested the Runtime to terminate it in an unusual way. Please contact the application's support team for more information. Should I submit a bug report or is this a known issue? It's an MKV file. Thanks, Dennis

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Dark_Shikari
by phil_rhodes＠rocketmail.com 17 Jun '10

17 Jun '10

Hi all. I'm posting this, not without some regret, at the behest of a few other people who felt the same way. What follows is an open letter regarding a situation we feel there's no other way to address. Begin quote This is an open letter from a group of ffmpeg users (not devs) who wish to complain about the behaviour of the user Dark_Shikari in the #ffmpeg IRC channel on freenode. We're complaining in this way for two reasons: 1) We have been unable to identify an individual in overall charge of the #ffmpeg channel or indeed the ffmpeg project in general. Nickserv reports that user md, founder of #ffmpeg, was last seen more than a year ago, so we're throwing this out in public in the hope that those who need to hear this will hear it. 2) The #ffmpeg channel is a prime contact point for ffmpeg users, particularly those seeking technical support. Channel operators there are, de facto, representatives of the project. Their behaviour reflects on the entire project and on Free and Open Source Software in general. We feel that Dark_Shikari's behaviour is too often that of the arrogant pedant, giving trivial, obvious or deliberately unhelpful responses to questions. For instance: <@Dark_Shikari> mik3: read the error! <@Dark_Shikari> [mpeg1video @ 0x84b5010]MPEG1/2 does not support 5/1 fps <mik3> i don't know what that means <@Dark_Shikari> I'm not sure what there is to understand Also: <Hfuy> Can I have AAC audio instead? it's what I sort of wanted anyway. <@Dark_Shikari> Hfuy: then tell it to encode aac. While we wish to give Dark_Shikari the benefit of the doubt, he takes this attitude so commonly that it is almost impossible to avoid the assumption that he is being deliberately petulant and pedantic. He is certainly being redundant and patronising. While we hesitate to attempt to psychoanalyse Dark_Shikari's attitude, it has to date been typified by sophistry connected to his status as a respected software engineer, and his presumed and wholly inaccurate assumption of our status somehow infinitely lower than that. To our knowledge this has been the situation for at least several years. We are aware of Dark_Shikari's contributions to the x264 project and its impact on high-quality FOSS encoding tools. We wish to take nothing away from him as a software engineer. However, we ask that: - Dark_Shikari realises that while he has expertise in at least one area, we have expertise, perhaps exceeding his, in others. We expect the same level of professionalism from him as we would any of our other colleagues in the field of digital media. - The controlling entities of #ffmpeg acknowledge that Dark_Shikari continues to be an extremely disruptive presence, regardless of his expertise, is unsuitable to be a representative of the ffmpeg project, and as such should not hold channel operator status. Yours: - Phil "Hfuy" Rhodes (phil at philrhodes.com ) - Michael "mahoney" Revelle (mrevelle at e-vergent.com) - Jan "Jan`" Hogevold (kerynasta at yahoo.com) - Two more users who do not wish to be named.

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