August 2007 - 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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lavc or xvid
by Alex Samad 06 Sep '07

06 Sep '07

Hi I have recently purchase a video camcorder, which records mpeg2 files. I am running through some tests between xvid and the lavc encoders. They xvid seems to produce smaller end files. as I am new to encoding/mencoder I thought I would ask the list. What are the main difference between the 2. Whilst doing a bit of research I also came across x264, found a codec head off report at doom9, but did not actually make too much out of it. my current tests that I am running is for each mpeg2 file encode at 800 , 1200 1600 kbit for lavc I am doing a 3 pass encode, whilst also changing the ac3 to lame for xvid I am doing a 2 pass encode, again whilst doing a change to the sound this is the lavc options I am using vcodec=mpeg4:threads=2:mbd=2:mv0:trell:v4mv:cbp:last_pred=3:predia=2:dia=2:vmax_b_frames=2:vb_strategy=1:precmp=2:cmp=2:subcmp=2:preme=2:qns=2:aspect=16/9:dc=10:vbitrate=$VBITRATE these are the xvid options I am using threads=2:chroma_opt:vhq=4:bvhq=1:quant_type=mpeg:aspect=16/9:bitrate=$VBITRATE my vf options -vf softskip,hqdn3d=2:1:2 -aspect 16:9 for some reason the camera can record in 16:9, but doesn't record the fact in the mpeg2 stream! so I have to place it encoding. audio options -oac mp3lame -lameopts preset=standard I have just realised I might not need to do this on the first pass! Another question what options do i need in the first past. Looking to speed the process up Thanks Alex

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Decoding UFC OnDemand movies
by Christopher Edward Nolan 31 Aug '07

31 Aug '07

Has anyone figured out how to do this so I can get them to play on mplayer?

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error decoding h264
by Lucas Pereira Gomes Linard 31 Aug '07

31 Aug '07

Hi, I've tried to conver a mp4 or mkv file (the codec is h264) with many commands but always get the same error. "Skipping frame! [h264 @ 0xda4220]no frame!60.58fps Trem: 4min 321mb A-V:0.037 [4954:192] Error while decoding frame! Pos: 4.3s 141f ( 0%) 61.07fps Trem: 4min 340mb A-V:0.067 [4840:192] Skipping frame! [h264 @ 0xda4220]no frame!61.29fps Trem: 4min 339mb A-V:0.037 [4840:192] Error while decoding frame! [h264 @ 0xda4220]no frame!61.72fps Trem: 4min 337mb A-V:0.040 [4840:192] Error while decoding frame! Pos: 4.3s 144f ( 0%) 62.15fps Trem: 4min 336mb A-V:0.043 [4840:192] 1 duplicate frame(s)!" I'm using the command found at the mplayer documents to convert a file to a dvd (mpg) mencoder -oac lavc -ovc lavc -of mpeg -mpegopts format=dvd:tsaf \ -vf scale=720:480,harddup -srate 48000 -af lavcresample=48000 \ -lavcopts vcodec=mpeg2video:vrc_buf_size=1835:vrc_maxrate=9800:vbitrate=5000:\ keyint=18:vstrict=0:acodec=ac3:abitrate=192:aspect=16/9 -ofps 30000/1001 \ -o movie.mpg movie.avi

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Re: [MEncoder-users] Unplayable flv movies
by Ade 30 Aug '07

30 Aug '07

On Wed Aug 29 15:56 , ReimarDöffinger <Reimar.Doeffinger(a)stud.uni-karlsruhe.de> sent: > On Wed, Aug 29, 2007 at 04:33:44PM +0100, Ade wrote: > [...] >> If you can shed anymore light on how those two files differ it would >> put my mind at ease. Also if you could point me at any analysis tools >> perhaps I can look myself to save you the trouble. > > You don't need an analysis tool, a text editor will do fine. The first > file contained exactly the text I quoted! You managed to munge part of > mencoders output into the file - and it obviously isn't playable then. > Not to mention the security/privacy issues that would mean even if it > did play... > Aha, thanks Reimar. I can see where it is all going wrong now. I have been using a daemon process to fire off the shellscript and it looks as though mencoders stderr has been redirected into the output file. I guess the daemon has its file handles in a twist. I have redirected stderr to /dev/null and now all is fine. Probably the root of my problems from day one. Groan. Have a spotters badge! Many Thanks. Ade.

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Re: [MEncoder-users] Unplayable flv movies
by Ade 29 Aug '07

29 Aug '07

Thanks for the quick reply Reimar. On Wed Aug 29 13:09 , ReimarDöffinger <Reimar.Doeffinger(a)stud.uni-karlsruhe.de> sent: > Hello, > On Wed, Aug 29, 2007 at 12:36:33PM +0100, Ade wrote: >> An example file is here: >> http://67.19.246.210/flv/810567956-1.flv >>mencoder command line was: >> mencoder -ofps 15 810567956-1.wmv -of lavf -lavfopts format=flv -ovc >> lavc -lavcopts >> vcodec=flv:autoaspect:vbitrate=300:vqmin=2:vqmax=31:vme=5:mbd=1:subq=5:keyint=250 >> -af resample=22050:0:0,channels=2 -oac mp3lame -lameopts >> cbr:br=64:aq=2:highpassfreq=-1:lowpassfreq=-1 -o 810567956-1.flv > > I don't believe you that this was the commandline used for the sample > file. > Or can you explain how this could end up in the sample file with above > command: > " > Video stream: 791.730 kbit/s (98966 B/s) size: 1959532 bytes 19.800 > secs 497 frames > > Audio stream: 64.000 kbit/s (7999 B/s) size: 157988 bytes 19.749 > secs > =============== > Opening video decoder: [dmo] DMO video codecs > Creating new registry > DMO dl^@A@I8^@^@^@^@s VO Optimizations 0 1 > DMO dll might use previous sample when requested > GetOutput r=0x0 size:1244160 align:1 > StreamCount r=0x0 1 1 > Decoder supports the following formats: YV12 YUY2 UYVY YVYU RGB8 RGB555 > RGB565 RGB24 RGB32 > " Hmm, I can see the bitrates don't match at all for the video compared to the cmdline. Anyway, further to my other discussion on the ffmpeg list I completely cleaned my system of old av libraries and recompiled from scratch. In answer to your query I re-ran from the commandline the above (previously it was run from a batchfile) and once again produced the 2.1MB file here: http://67.19.246.210/flv/mencoder.flv ...but this time it plays fine through martijndevisser's flv player! I have no answer as to what happened to the previous one, but that cmd was lifted from my batchfile. The only difference is the cleanse and recompile of the binaries. It seems odd that the size of the file is so similar. If the bitrate was far lower wouldn't the file be much smaller?? If you can shed anymore light on how those two files differ it would put my mind at ease. Also if you could point me at any analysis tools perhaps I can look myself to save you the trouble. Many thanks for the help, Ade -- Using Opera's revolutionary e-mail client: http://www.opera.com/mail/

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Unplayable flv movies
by Ade 29 Aug '07

29 Aug '07

Hi All, I have been trying to convert about 3000 user submitted videos to FLV but I am having some problems with mencoder's output format. An example file is here: http://67.19.246.210/flv/810567956-1.flv mencoder command line was: mencoder -ofps 15 810567956-1.wmv -of lavf -lavfopts format=flv -ovc lavc -lavcopts vcodec=flv:autoaspect:vbitrate=300:vqmin=2:vqmax=31:vme=5:mbd=1:subq=5:keyint=250 -af resample=22050:0:0,channels=2 -oac mp3lame -lameopts cbr:br=64:aq=2:highpassfreq=-1:lowpassfreq=-1 -o 810567956-1.flv ...and output header is: MEncoder dev-SVN-r24278-3.4.6 (C) 2000-2007 MPlayer Team CPU: Intel(R) Celeron(R) CPU 2.40GHz (Family: 15, Model: 2, Stepping: 9) CPUflags: Type: 15 MMX: 1 MMX2: 1 3DNow: 0 3DNow2: 0 SSE: 1 SSE2: 1 Compiled for x86 CPU with extensions: MMX MMX2 SSE SSE2 I used the standard ./configure. Can anyone analyse that file, what I am doing wrong, or if you need anymore information? I could also produce smaller files if needed - it is consistent. As a note, ffmpeg converts this input but produces a garbled output on a number of my videos, or cannot convert, whereas outputing to mpeg or such through mencoder produces much more reliable conversion (just not in flv format which I need). Cheers, Ade -- Using Opera's revolutionary e-mail client: http://www.opera.com/mail/

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Re: [MEncoder-users] MPEG-2 muxer
by Nico Sabbi 27 Aug '07

27 Aug '07

Nicolas Hesler wrote: > Nico Sabbi wrote: > >> Nicolas Hesler wrote: >> >>> So when Mencoder muxes a file, it tries to ensure sync. >>> Do demuxers (like MPEG StreamClip) then retain that sync or it is >>> the same result as going to two separate files directly from Mencoder? >>> >> I don't know what that program is >> > I know. I was a little unclear. > > What I know: > > 1. mencoder will mux and retain sync as much as possible because it is > aware of timestamps. > 2. going directly to 2 separate files will potentially create sync > problems because it is not using timestamps. > > Basically, what I want to know is: > > - if I take the muxed file that mencoder produced and then demux it, > will I have the same result as when you go directly to 2 separate > files? of course yes > or will the 2 demuxed files produced from the Mencoder file have > potentially better sync than going directly to 2 separate files? > potentially worse, not better. It seems that users don't realize that mpeg files produced by mencoder may have slight temporal discontinuities, e.g. few consecutive timestamps (without considering b-frames) may be: 0.40, 0.80, 1.20, 2.0, 2.40, 2.80, 3.60, 4.00 and so on ^^ gap here ^^^ gaps are introduced when mencoder inserts 0-length frames to keep sync (similar to N-frames in avi). Demuxing the file you will lose those gaps, so remuxing the elementary stream files will result in a mux containing (possibly) different timestamps than in the original file (and surely won't contain the gaps supposed to keep the streams in sync)

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MPEG-2 muxer
by Nicolas Hesler 27 Aug '07

27 Aug '07

Is there any kind of syncing advantage when going from a source to a muxed Mpeg-2 file over doing 2 separate files (.m2v and .ac3 for instance)? I'm finding that for compatibility with DVD authoring software, I have to demuxed the muxed mpeg-2 file anyway. Is there a difference (sync or otherwise) between going directly to a muxed mpeg-2 file and eventually demuxing OR not muxing at all and creating two separate files (m2v and ac3)?

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