April 2009 - MEncoder-users - lists.mplayerhq.hu

Help with MPG video encoding
by Walter Belhaven 20 Apr '13

20 Apr '13

Hi, I've got a question on how to get the best possible MPG encoding of a movie source, "at any price" so to speak -- i.e., as many bits as the encoder needs to get the highest possible video quality. It appears to me that the MPG encoding process is introducing artifacts that are present regardless of the amount of "free reign" I give to the encoder with respect to quantization, bitrate, and the like. My bottom line question is thus: "Are these artifacts inherent in MPG encoding, or am I just not twiddling the knobs and dials on the encoder correctly?" Here's all the details ... My source is a mixed hard- and soft-telecined "movie" at 1080/60i that I'm trying to tanscode to 480/24p, soft telecined to 480/60i, for ultimate burning to an NTSC DVD-Video. When I use mencoder to inverse telecine, crop out the crud, expand back to the original letterbox ratio (it's 2.35:1, not 16/9), and 'encode' the video with HUFFYUV (422P), the resulting video looks stunning, with no 'blocking' artifacts to speak of. This, of course, is as expected. But when I encode the video in MPG2 or MPG4, even with vqscale=1 or vqscale=2, I see sometimes severe blocking in the resulting video. Is this because the chroma is being subsampled vertically and horizontally (4:2:0), or is it because 'vqscale' is (perhaps necessary but) not sufficient to get "maximum quality at any price" encoding? Thanks, WB ____________________________________________________________________________________ Be a PS3 game guru. Get your game face on with the latest PS3 news and previews at Yahoo! Games. http://videogames.yahoo.com/platform?platform=120121

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B-frames and GOP with MPEG-2 for DVD
by Nicolas Hesler 16 Apr '11

16 Apr '11

Can anyone offer any input to the following command line? I've been trying to refine for the highest possible quality of MPEG-2 while staying DVD compliant. The source is 24fps. (Note: format=mpeg2, because format=dvd does not work with Adobe Encore 2.0). From what I understand, keeping GOP open, improves quality. Is this true? Is it 100% DVD compliant? Do I want to introduce B frames in my encoding? (The vb_strategy part of my command line is currently useless, right?) If parts of my video are reaching into 9-10 Mbs bitrate, would it beneficial to introduce B-Frames? Will it improve quality? (This is probably a stupid question) Are the sync issues with bframes only relevant to mpeg4 or lavf? mencoder -oac lavc -ovc lavc -of mpeg -mpegopts format=mpeg2:tsaf:telecine / -vf scale=720:480,harddup -mc 0 -noskip -srate 48000 -af lavcresample=48000:0:2 -lavcopts / vcodec=mpeg2video:vrc_buf_size=1835:vrc_maxrate=7000:vbitrate=6000:keyint=12 / :trell:mbd=2:precmp=2:subcmp=2:cmp=2:dia=-10:predia=-10:cbp:mv0:vqmin=1:lmin=1 / :dc=10:vpass=1:vb_strategy=2:acodec=ac3:abitrate=224:aspect=16/9:vstrict=0 -ofps 24000/1001 -o $output $input

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AV sync issues with seperate audio and video encodeing
by ilyail3 K 07 May '09

07 May '09

I'm a novice in the field of video encoding, but some project of mine requires me to encode movies to mp4 with video encoding of h264 and audio libaac or liblame. I've tried encoding it with lavf , but it gives me the creepy warning about the b frames do b frames have significant contribution to the quality of the video in x264? I figured out that the best way to use b-frames and mux to mp4 is with MP4Box. but every time I get a bad A-V sync issue of about 30 seconds. I've tried everything , extracting the video with ffmpeg with -async , or with mplayer it doesn't seem to make any difference. can somebody please post an example of how to create .mp3(for example) files and .h264 files(raw h264). mux them with MP4Box and get a prefect audio-video sync. besides that small issue , you program is by far superior to ffmpeg.

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Status with MEncoder muxrate problem?
by Francois Visagie 01 May '09

01 May '09

Hi All, For my use MEncoder is a fantastic utility and I've invested literally months setting up the perfect encode for DV AVI to DVD-compliant MPEG-2. The problem is, when it comes to encoding actual full-length projects it regularly bombs out with buffer underflow messages such as: BUFFER UNDEFLOW at stream 0, raising muxrate to 11088 kb/s The command line I use contains DVD-compliant bitrate and other specifications: mencoder -field-dominance 1 -mc 0 -vf hqdn3d=2:1:2,harddup -oac lavc -ovc lavc -lavcopts abitrate=128:acodec=ac3:autoaspect:ilme:ildct:keyint=15:mbd=2:top=0:trell:vbitrate=%BITRATE%:vcodec=mpeg2video:vrc_buf_size=1835:vrc_maxrate=9800:vstrict=0%PSNR%:vmax_b_frames=2%VB_STRAT%:dia=2:preme=2:predia=2:mbcmp=6:precmp=2:cmp=2:subcmp=6:last_pred=2:mv0:mv0_threshold=0 -of mpeg -mpegopts format=dvd:tsaf %1 -o %OUTPUT% >%OUTPUT%.%PASS%.txt This problem seems widely reported on the Internet but I haven't found any solutions to it. All versions of MEncoder I've tried so far have the problem with slight variations in behaviour. 1) To your knowledge has this problem been fixed and if so, in what release/SVN? 2) The problem seems to be with the _muxrate_. After encoding, I split the video and audio into elementary streams for DVD authoring, where only the video and audio bitrates matter. So personally I don't really care what muxrate _MEncoder_ uses. What would be a sensible way of determining what muxrate to specify to avoid this problem? Keeping in mind video and audio streams need to remain DVD-compliant. Many thanks in advance, Francois

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Re: [MEncoder-users] avi seek and keyframe problem
by sebastianelsner＠freenet.de 25 Apr '09

25 Apr '09

Am 23.04.2009, 06:19 Uhr, schrieb RC <cooleyr(a)gmail.com>: On Mon, 20 Apr 2009 16:05:18 +0200 "Sebastian Elsner" <sebastianelsner(a)freenet.de> wrote: But if I want to seek in the resulting avi it takes ages to find the index because there are no keyframes in the file (virtual dub tells me this) VirtualDub is wrong. No doubt it simply doesn't support an index in ODML chunks, and so doesn't fully support files larger than 2GB. If you can keep your avi under 2GBs, you can use -noodml Virtual dub also reports no keyframes with noodml set, which would refute what you are saying. The strange thing is, my avis are not working if they get over 1,1 GB (i tried ffmpeg too). Setting the NOODML flag with mencoder helps getting them to play. but also leaving the odml flag out produces avis without "keyframes" (which play if they are smaller 1,1GB). This is the whole history: the files: 2048x1280 jpegs used codec: stream copy Started off with ffmpegs -vcopy Problem: Could not play files bigger 1GB. They were just black. Files smaller 1GB worked and had keyframes to seek. Moved on to mencoder -ovc copy (as described in docs) files do not have keyframes - so no seeking or scrubbing - doesnt matter with or without -noodml files > 1,1GB worked personally i like mencoder better so i would like to stick with it. The command line didn't change to my first post - so what can I do. Any suggestions? Please help me! Thanks Sebastian Heute schon ge"freeMail"t? Jetzt kostenlose E-Mail-Adresse sichern! http://email.freenet.de/dienste/emailoffice/produktuebersicht/basic/mail/in…

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Pulsing Pixelation (?I Frames) in MPEG2 output
by iFrame problems 25 Apr '09

25 Apr '09

I've recently had a lot of trouble transcoding to mpeg2 with mencoder (SVN-r29092-4.2.4 on Kubuntu/Hardy). Parameters that produce the problem for me are: *mencoder -endpos 5 -of mpeg -mpegopts format=dvd:tsaf -vf scale=640:,expand=720:576,harddup -ovc lavc -lavcopts vcodec=mpeg2video:keyint=15:vbitrate=1000:vrc_maxrate=7500:vrc_buf_size=1835: nr=400:trell=yes:mbd=2:mv0:predia=2:dia=2:preme=2:precmp=2:subcmp=2:cmp=2:vstrict=0:aspect=4/3 -oac copy -o output.mpg input.avi* The output had pulses of blocky pixelation which seemed to occur on I Frames (same frame frequency as keyint=) and then rapidly corrected over one or two frames. This was most evident on spacially complex scenes (eg winter forest) or static pics with sharp edges (logos). It also seems to mainly occur on bigger source files (>175mb), even if only a small amount (5sec) is transcoded. After considerable time spent trying to adjust the bitrate, number of passes, motion detection and other settings, I finally removed the lavc option nr=400 with immediate resolution of the problem (all other settings reverted to original format OK). I'm not sure if this is a known issue, but thought I'd mention it to possibly save others some time.

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Trying to use Nero's AAC encoder, having trouble converting audio to intermediate lossless format
by Andrew Berg 23 Apr '09

23 Apr '09

Nero's encoder is supposed to be much better than FAAC, so I'm trying to use it. However, I can't seem to use FLAC or even PCM as an intermediate. If I try to use lavc to convert to FLAC, I get messages telling me the output buffer is too small. If I use -oac pcm, I have no way to mux the raw PCM stream into a WAV container because MEncoder says a video stream is mandatory and refuses to process the file. I can use FAAC at the highest quality setting, but that's not lossless. I would prefer to use FLAC, since it is probably faster (FLAC is a fast compressor and there is less written to disk). Source audio is AC3 in an MPEG-2 container, if that matters.

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avi seek and keyframe problem
by Sebastian Elsner 23 Apr '09

23 Apr '09

Hello! I am using menconder to make a motion jpeg avi file out of a sequence of jpegs. I'm using a slightly modified syntax, which is in the docs: mencoder mf://*.jpg -mf w=800:h=600:fps=25:type=jpg -ovc copy -ffourcc MJPG -noodml -o output.avi Works fine! But if I want to seek in the resulting avi it takes ages to find the index because there are no keyframes in the file (virtual dub tells me this) so the player is seeking through the whole frame from the beginning. Any chance to get myself a keyframe at every frame? -idx or -forceidx doesn't seem to work. Is this a bug? See the current encoder output below. Thanks Sebastian encoding with mencoder... MEncoder Sherpya-SVN-r28311-4.2.5 (C) 2000-2009 MPlayer Team CPU: Intel(R) Core(TM)2 Quad CPU @ 2.40GHz (Family: 6, Model: 15, Stepping: 7) CPUflags: Type: 6 MMX: 1 MMX2: 1 3DNow: 0 3DNow2: 0 SSE: 1 SSE2: 1 Compiled with runtime CPU detection. success: format: 16 data: 0x0 - 0x0 MF file format detected. [mf] number of files: 841 VIDEO: [IJPG] 2048x1108 24bpp 24.000 fps 0.0 kbps ( 0.0 kbyte/s) [V] filefmt:16 fourcc:0x47504A49 size:2048x1108 fps:24.000 ftime:=0.0417 videocodec: framecopy (2048x1108 24bpp fourcc=47504a49) Forcing output FourCC to 47504a4d [MJPG]. Writing header... ODML: Aspect information not (yet?) available or unspecified, not writing vprp header. Writing header... ODML: Aspect information not (yet?) available or unspecified, not writing vprp header. Writing index...41f (100%) 16.00fps Trem: 0min 1087mb A-V:0.000 [260317:0] Writing header... ODML: Aspect information not (yet?) available or unspecified, not writing vprp header. Video stream: 260317.647 kbit/s (32539705 B/s) size: 1140245528 bytes 35.042secs 841 frames done encoding

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recent significant mencoder slowdown
by Matyas Sustik 23 Apr '09

23 Apr '09

Dear Forum, I experience major mencoder slowdown with recent versions. The last fast version I have is r28850. The one compiled today run 6x slower. Since others do not mention this, maybe this effects some specific encodes only. And of course it is possible that I am doing something foolish. (I did not stop all non-essential processes for testing. I reinstalled the package created with 'fakeroot debian/rules binary' between the tests.) How would I troubleshoot what is going on here? Could this be because of a compiler issue? Should I check out the old version and recompile to test? (I only have the deb package for the fast version.) Your comments are appreciated. Matyas - Every hardware eventually breaks. Every software eventually works.

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Re: [MEncoder-users] Freeze with SIGINT/SIGHUP when encoding from http stream
by Lee Jackson 22 Apr '09

22 Apr '09

I've managed to fix this but I had to make some changes to the way the stream/cache2.c exit code works. Its a simple fix and I can put a patch together but I cant see where to submit it too...can anyone point me in the right direction please? Tia Lee ------------------------------ Message: 2 Date: Mon, 20 Apr 2009 13:11:20 -0700 From: "Lee Jackson" <leej(a)sowhatresearch.com> Subject: [MEncoder-users] Freeze with SIGINT/SIGHUP when encoding from http stream To: <mencoder-users(a)mplayerhq.hu> Message-ID: <228AA64DFD5D4044A04F763A65659DAA55029A(a)EXVBE012-14.exch012.intermedia.n et> Content-Type: text/plain; charset="iso-8859-1" Brief background - in order to produce several simultaneous versions of a live recording (in real time) I am taking input from a capture card and using VLC to serve it via http. e.g. cvlc v4l2:// :v4l2-dev=/dev/video0 :v4l2-adev=\"plughw.UA25\" :v4l2-standard=0 :v4l2-width=720 :v4l2-height=576 :v4l2-fps=25 --sout '#transcode{vcodec=mp2v,vb=6000,deinterlace,acodec=mpga,ab=128,channels= 2}:duplicate{dst=std{access=http,mux=ps,url=localhost:8080}}' I am then trying to transcode this stream which again works, HOWEVER mencoder will often freeze when I send it a SIGINT/SIGTERM/SIGHUP signal or when I press ctrl-c to terminate the encoding. This happens both with the mpeg and x264 versions that I am creating e.g. mencoder http://127.0.0.1:8080 -ofps 30 -v -vf scale=320:-10,harddup -lavfopts format=mp4 -faacopts mpeg=4:object=2:raw:br=96 -oac faac -ovc x264 -sws 9 -x264encopts nocabac:level_idc=13:bframes=0:global_header:threads=auto:subq=7:framere f=3:partitions=all:trellis=2:chroma_me:me=umh:bitrate=300 -of lavf -o test1.mp4 The freezing is intermittent but happens more than 50% of the time. I've tried the latest SVN version of mencoder and this problem is still present. HOWEVER this is only happening when I do the transcode on http stream - if I trancode from an mpeg file theres no problem. The freeze is a major problem for me since its generating corrupt mp4 files.... Can anyone offer any assistance in suggesting how I might solve this problem? Tia Lee

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