June 2005 - ffmpeg-user - lists.ffmpeg.org

ffetc
by runlevel_4＠passagen.se 08 Jun '05

08 Jun '05

my kernel 2.4.2-8, crashed due to ffserver (funny raid resync for 6 fucking hours) patent-thingy-problems for ffmpeg/ffserver video aint smooth, it's choppy why not keep ffmpeg/ffserver simple with a few cross-platform codecs or kill the son of a bitch

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Re: direct stream copy with ffmpeg
by vvatashki＠gmail.com 08 Jun '05

08 Jun '05

>It certainly should be - and it is equally certainly there in the man >page, at least on my end. What version are you using? I'm using ffmpeg from cvs two days old :) > 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. Let we have a divx avi video.Direct stream copy is divx frame is taken from the source video and put in the output file. Recompression means to take that divx frame decompress it with divx to get the raw bitmap and then use again codec to compress it.This is very CPU intensive compared to the first way.And there is loss of quality I didnt find stream copy in FFmpeg,but in mencoder. The syntax is mencoder movie.avi -oac copy -ovc copy -endpos 00:01:00 -o preview.avi That way I capture only one minute from the movie with the same quality. >"Direct stream copy", in MPlayer and I believe in FFmpeg, appears to >mean "byte-for-byte duplication of the input stream". I think that copying is done frame by frame.That way you can crop video, but for example resize and etc. you have to do full processing to the video -- Venci Vatashki

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Does ffmpeg support piping avi?
by xiebopublic＠gmail.com 07 Jun '05

07 Jun '05

Hi, "cat x.mpg | ffmpeg -i - ..." works well, but "cat x.avi | ffmpeg -i - ..." fails. Does ffmpeg support piping avi? Thank you! Best Regards, Xie Bo

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3gp encoding
by kram.me＠gmail.com 07 Jun '05

07 Jun '05

Hi I am trying to encode 3gp video using ffmpeg. I have problem encoding the audio stream. Does anyone information on 3gp video encoding? thank you mark

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Create movie trailer with ffmpeg
by vvatashki＠gmail.com 07 Jun '05

07 Jun '05

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

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banding artefacts when encoding very subtle gradients
by notnot＠xs4all.nl 07 Jun '05

07 Jun '05

Hello all, I'm encoding a computer animation which has very subtle moving gradients, the color is nearly grey. I generate mpeg-2 files with low compression from piped .ppm images. During quiet moments in the animation, you see ugly banding artefacts. When there is more motion, I cannot see the banding any more. Are there any low-level settings I can change to increase quality? Right now, this is my command : PleinMuseum final.script | ffmpeg -f imagepipe -img pnm \ -i - -i bounce_0506.wav \ -target "pal-dvd" -aspect 4:3 -acodec mp2 -ab 128 \ -hq -b 8000 -maxrate 8000 -minrate 8000 -dc 10 PM-DV-p1.mpg I'm very interested in any tips to improve quality, but sadly I'm running out of time for the deadline... Thanks, Erwin Driessens www.xs4all.nl/~notnot

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AVPacket memory management
by will＠misconception.org.uk 07 Jun '05

07 Jun '05

I'm having problems with my applications management of AVPacket structures. I have a player that works seemingly perfectly with and MPEG2 stream, including being valgrind clean. However, when I try to play an MPEG4 stream I get a lot of errors from avcodec telling me the stream is broken in various ways. Removing all calls to av_free_packet corrects the problem, but leaks memory. I have one thread that does: while (1) { av_read_frame(pkt) queue_packet(pkt) av_free_packet(pkt) } The queue_packet() call looks like: queue_packet(pkt) { new_pkt = av_malloc(sizeof(AVPacket)) memcpy(new_pkt, pkt, sizeof(AVPacket)) av_dup_packet(new_pkt) } Is this logic correct? How can freeing this packet cause problems, surely the combination of memcpy and av_dup_packet will completely isolate the data? Why does my code work with MPEG2 and not MPEG4? I have looked at the ffplay.c source code but in this regard it doesn't seem to do more than what I am doing.

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Large file support
by mbardiaux＠peaktime.be 06 Jun '05

06 Jun '05

Is ffmpeg able in theory to convert a 6GB wmv file to MPEG1? More precosely, I have to write an app that would sequentially read the WMV, and make an MPEG-1 for every 15 minutes. Would the huge file size of the wmv be a problem? -- Michel Bardiaux Peaktime Belgium S.A. Bd. du Souverain, 191 B-1160 Bruxelles Tel : +32 2 790.29.41

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Chapter description in case of DVD using FFMpeg
by sunil_j＠conceptemsys.com 06 Jun '05

06 Jun '05

Hi, Can anyone let me know, if I can read Chapter description in case of DVD, using FFMpeg. In case if it is possible then which API's I have to use. Do let me know. Thanks, Sunil

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Large (>2gb) mp4/mov output files are not written correctly by ffmpeg
by chalserogers＠gmail.com 04 Jun '05

04 Jun '05

I'm trying to transcode a dvd into an mp4/mov (something readable by Quicktime), and fit it onto a DVD-RW (so <= 4gb ish). Whenever the final output file is larger than a certain size, which I think is 2gb (1.9gb files work, 2.5gb files don't) the result is unplayable (in mplayer, totem, and quicktime) and ffmpeg returns obviously wrong statistics. This doesn't depend upon the detailed options (bitrate/audio bitrate, -hq, multiple passes), and happens on files from at least two dvds. Identical options, except with a bitrate small enough to keep the output file < 2gb produces working files. Command line: ffmpeg -i Windows\ Documents/DVD\ Rips/Spirited\ Away/VTS_01_1.VOB -b 4000 -ab 160 -hq -pass 1 "Spirited Away.mp4" and output: ffmpeg version 0.4.9-pre1, build 4756, Copyright (c) 2000-2004 Fabrice Bellard configuration: --enable-gpl --enable-mp3lame --enable-libogg --enable-vorbis --enable-theora --enable faad --enable-faac --enable-xvid --enable-a52 built on Jun 4 2005 17:10:26, gcc: 3.3.5 (Debian 1:3.3.5-8ubuntu2) Input #0, mpeg, from 'Windows Documents/DVD Rips/Spirited Away/VTS_01_1.VOB': Duration: 00:03:43.0, start: 0.223733, bitrate: 237252 kb/s Stream #0.0[0x1e0]: Video: mpeg2video, yuv420p, 720x480, 29.97 fps, 9801 kb/s Stream #0.1[0x80]: Audio: ac3, 48000 Hz, 5:1, 448 kb/s Stream #0.2[0x81]: Audio: ac3, 48000 Hz, 5:1, 384 kb/s Stream #0.3[0x82]: Audio: ac3, 48000 Hz, stereo, 192 kb/s Stream #0.4[0x20]: Subtitle: dvdsub Stream #0.5[0x21]: Subtitle: dvdsub Output #0, mp4, to 'Spirited Away.mp4': Stream #0.0: Video: mpeg4 (hq), yuv420p, 720x480, 29.97 fps, q=2-31, pass 1, 4000 kb/s Stream #0.1: Audio: aac, 48000 Hz, stereo, 160 kb/s Stream mapping: Stream #0.0 -> #0.0 Stream #0.1 -> #0.1 Press [q] to stop encoding frame=224073 q=0.0 Lsize=-1930880kB time=7476.4 bitrate=-2115.7kbits/s video:1680272kB audio:168862kB global headers:0kB muxing overhead -204.420806%

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