November 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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2pass: auto-calculation of bitrate?
by Ilya Zakharevich 25 Nov '08

25 Nov '08

I'm looking for a way to let mencoder (I use xvid) to automatically select the 2-pass average video bitrate based on the contents. I'm pretty sure that most (if not the all) of the logic to do it is already there, but I can't find the UI to trigger this behaviour. A) For example: suppose I have 100 videos; now a) append them all together; b) do 2-pass encoding of them all with, e.g., 1200kb/sec bitrate; c) split the result into 100 video files. This way, mencoder will automatically assign some "appropriate" average bitrate to each video. B) Now suppose that I have only 1 video, but I have all 100 logs of pass=1 for all 100 videos. Theoretically, this is all which is needed to do an equivalent of a/b/c for this particular video. How to convince mencoder to use these extra log files? C) Now suppose that I have only 1 video, and only 1 log of pass=1 for this video. It is more or less obvious that all I need from the remaining 99 logs is very short "summaries". How to create the summaries, and how to "feed" them to mencoder? D) And now the last logical step: If of these 99 remaining videos 40% is "action-like", 40% is "arthouse-like", and 20% is animation, then law of big numbers starts to be applicable. Essentially, I won't need to have summaries of the particular videos; I could feed in 40 copies of "average action-like summary", 40 copies of "average arthouse-like summary", and 20 copies of "average animation summary". So if I keep these summaries in ~/.mplayer in action.sum arthouse.sum animation.sum, then I could ask mencoder to do bitrate_from=1200,40*action+40*arthouse+20*animation and it could choose the appropriate bitrate. Is it possible to do now (possibly, with some pre-processing)? Any plans to have this? Thanks, Ilya

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Problem with rc2 (not present in rc1)
by Jesus Altuve 19 Feb '08

19 Feb '08

I can replicate the problem when the source video frame rate is unespecified/wrong OR when the source has a VERY low frame rate (cell phone videos) The problem is this.. rc1 will encode *ANYTHING* to flv without any problems using the following command line: rc1 version command line. ------------------------------------- mencoder PLAYBACK_ESPECTACULAR.wmv -of lavf -lavfopts i_certify_that_my_video_stream_does_not_use_b_frames -oac mp3lame -ovc lavc -channels 2 -vf scale=320:240 -lameopts cbr:br=32 -lavcopts vcodec=flv:vbitrate=350:mbd=2:turbo:keyint=8 -srate 22050 -o output.flv but... if I use rc2 I experience a strange problem... rc2 version command line (same as above except for the -lavfopts option) ------------------------------------ mencoder PLAYBACK_ESPECTACULAR.wmv -of lavf -oac mp3lame -ovc lavc -channels 2 -vf scale=320:240 -lameopts cbr:br=32 -lavcopts vcodec=flv:vbitrate=350:mbd=2:turbo:keyint=8 -srate 22050 -o output.flv The problem with rc2 is this: If the source video has an 'incorrect' frame rate (I have a video that reports frame rate as 99999) then the resulting video plays too fast, so I decided to add to the rc2 command the -ofps 24 flag.. and bingo, it works.. because it limits the fps to 24... now, the ofps solves the problem when the source FPS is too high/wrong.. however, if the source FPS is too low (cell phone videos) the encoded video will play too fast.. My problem is that this does NOT happen with rc1!! is there a way to tell mencoder to 'limit' the FPS to a certain value but ONLY if the source FPS is above *THAT* value? I already tried -fps -ofps, -mc 0 I still have to experiment with -noskip Thanks!

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high quality mjpeg
by Morris Beverly 03 Dec '07

03 Dec '07

I have a large (17GB, 1264x421 resolution, 7 minute long) quicktime animation file that I'm converting to mjpeg format for playing on a low powered system (VIA C7 1.3 Ghz, 1GB ram - this hardware is a fixed requirement). Using these options: -lavcopts vcodec=mjpeg:vhq:vbitrate=24000 I'm getting a 700MB file that plays back fine, but is lower quality than I would prefer (also this seems to only be about 13 mbits rather than the 24 mbits that I intended to get). I've tried using the ljpeg codec and got a 3GB file that looked very good, but didn't play quite smoothly enough. Most of the quality settings I've found in the docs seem to only apply to divx or other multi frame compression sort of codecs rather than just the basic mjpeg sort of codec. Do any of you have suggestions for getting a higher quality mjpeg file without going all the way to ljpeg? Also, am I using the vbitrate option properly? I'm willing to use other codecs as long as they would be usable on the low end hardware I'm tied to. thanks, morris

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Mencoder lame errors, and mpeg to avi batch process
by Dave M G 02 Dec '07

02 Dec '07

The Set Up: I'm running Ubuntu Gutsy, 7.10, and I've got mencoder, ffmpeg, and have installed every codec I can think of (Specifics listed below). I have a Sony HD video camera which writes everything in an uncompressed MPEG format. The camera connects by USB and behaves like an external hard disk - no need for DV capture utilities, just simple file transfers. The frame rate of the files is 30fps, and the size can be either 720X480, or 640X480. The video camera splits video at the 2 GB mark. I'm not sure of the exact megabyte to time ratio, but usually a 40 minute to an hour recording will result in two files, the first being exactly 2 GB, and the second a little over 1 GB. The Goals: What I want to do is store these recordings in a smaller more manageable format, like AVI. Ideally, what I'd like to do is: 1. Append the files together. They are always numbered like so: m2u00066.mpg, m2u00067.mpg, m2u00068.mpg. So, assuming that I want to merge all videos in a directory, append them in order of file number. 2. De-interlace. 3. Save in a reasonably high quality but smaller format, like an AVI. I understand that smaller file format equals some quality loss, but I don't need to preserve original quality, I just need a result that is clear. What I've Done: I found this script, mpg2avi, which uses mencoder to make the conversion. The results are an avi file of acceptable quality. http://www.linuxquestions.org/linux/answers/Applications_GUI_Multimedia/Bat… The problems: 1. Despite having lame installed, it keeps giving an audio codec not found error (reproduced below). 2. Does not seem to handle the 720X480 size. 3. I don't think it deinterlaces the video. 4. Has no option to append videos together. The question: Can these errors be resolved, and then the de-interlacing and appending functions added? Thank you for any advice. - - - - - Here are the errors I am seeing: MEncoder 2:1.0~rc2-0ubuntu1~gutsy1 (C) 2000-2007 MPlayer Team CPU: Intel(R) Pentium(R) D CPU 2.80GHz (Family: 15, Model: 6, Stepping: 2) CPUflags: Type: 15 MMX: 1 MMX2: 1 3DNow: 0 3DNow2: 0 SSE: 1 SSE2: 1 Compiled with runtime CPU detection. success: format: 0 data: 0x0 - 0x7dc70000 MPEG-PS file format detected. VIDEO: MPEG2 720x480 (aspect 3) 29.970 fps 9100.0 kbps (1137.5 kbyte/s) [V] filefmt:2 fourcc:0x10000002 size:720x480 fps:29.97 ftime:=0.0334 ========================================================================== Opening audio decoder: [liba52] AC3 decoding with liba52 Using SSE optimized IMDCT transform Using MMX optimized resampler AUDIO: 48000 Hz, 2 ch, s16le, 448.0 kbit/29.17% (ratio: 56000->192000) Selected audio codec: [a52] afm: liba52 (AC3-liba52) ========================================================================== Opening video filter: [expand osd=1] Expand: -1 x -1, -1 ; -1, osd: 1, aspect: 0.000000, round: 1 Opening video filter: [scale w=740 h=480] ========================================================================== Opening video decoder: [mpegpes] MPEG 1/2 Video passthrough VDec: vo config request - 720 x 480 (preferred colorspace: Mpeg PES) The selected video_out device is incompatible with this codec. Try appending the scale filter to your filter list, e.g. -vf spp,scale instead of -vf spp. VDecoder init failed :( Opening video decoder: [libmpeg2] MPEG 1/2 Video decoder libmpeg2-v0.4.0b Selected video codec: [mpeg12] vfm: libmpeg2 (MPEG-1 or 2 (libmpeg2)) ========================================================================== Audio LAVC, couldn't find encoder for codec mp3. - - - - - Here are the contents of the script: #!/bin/bash #mpg2avi (Convert mpeg streams into high quality mpeg4 avi with mp3 audio) #requirements: mplayer #Begin clear # variables version=0.2b current_directory=$( pwd ) # video bitrate (1100 = around 500 MB movie size) vbitrate=1100 echo -e "* mpg2avi v${version}" # remove spaces for i in *.[Mm][Pp][Gg]; do mv "$i" `echo $i | tr ' ' '_'`; done > /dev/null 2>&1 & # remove uppercase for i in *.[Mm][Pp][Gg]; do mv "$i" `echo $i | tr '[A-Z]' '[a-z]'`; done > /dev/null 2>&1 & # convert mpg movies into avi's with mencoder for i in *.[Mm][Pp][Gg]; do nice -n 10 mencoder $i -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=$vbitrate:vhq:vqmin=2:vlelim=-4:vcelim=9:lumi_mask=0.05:dark_mask=0.01 -vf pp=md -vf scale=720:480, -oac lavc -lavcopts acodec=mp3:abitrate=128 -o "`basename "$i"`.avi";echo "Conversion done";done exit; - - - - - And here is some additional informational output: $ mencoder -ovc help MEncoder 2:1.0~rc2-0ubuntu1~gutsy1 (C) 2000-2007 MPlayer Team CPU: Intel(R) Pentium(R) D CPU 2.80GHz (Family: 15, Model: 6, Stepping: 2) CPUflags: Type: 15 MMX: 1 MMX2: 1 3DNow: 0 3DNow2: 0 SSE: 1 SSE2: 1 Compiled with runtime CPU detection. Available codecs: copy - frame copy, without re-encoding. Doesn't work with filters. frameno - special audio-only file for 3-pass encoding, see DOCS. raw - uncompressed video. Use fourcc option to set format explicitly. nuv - nuppel video lavc - libavcodec codecs - best quality! vfw - VfW DLLs, read DOCS/HTML/en/encoding-guide.html. qtvideo - QuickTime DLLs, currently only SVQ1/3 are supported. libdv - DV encoding with libdv v0.9.5 xvid - XviD encoding x264 - H.264 encoding $ mencoder -oac help MEncoder 2:1.0~rc2-0ubuntu1~gutsy1 (C) 2000-2007 MPlayer Team CPU: Intel(R) Pentium(R) D CPU 2.80GHz (Family: 15, Model: 6, Stepping: 2) CPUflags: Type: 15 MMX: 1 MMX2: 1 3DNow: 0 3DNow2: 0 SSE: 1 SSE2: 1 Compiled with runtime CPU detection. Available codecs: copy - frame copy, without re-encoding (useful for AC3) pcm - uncompressed PCM audio mp3lame - cbr/abr/vbr MP3 using libmp3lame lavc - FFmpeg audio encoder (MP2, AC3, ...) twolame - Twolame MP2 audio encoder faac - FAAC AAC audio encoder -- Dave M G Ubuntu 7.10

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vf scale : same dimensions
by Nicolas Hesler 30 Nov '07

30 Nov '07

I'm writing a batch script and want to know if there is any harm in applying vf scale to the same dimensions. 720x480 source and then vf scale=720:480 Does mencoder actually perform a change to the video information or does it see that it's the same size and ignore the command? Thanks, Nic

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Ripping multiple DVD subtitles all at once
by Gustavo Tenrreiro 30 Nov '07

30 Nov '07

Hi, I am trying to integrate mencoder with another application that would allow it to rip DVDs to MPEG4s. I also want to make the subtitles available. I want to capture all subtitles available on the disc. >From the documentation I see you can capture a couple of subtitles while doing 2 pass encoding, but that leaves out the rest of the subtitles. Thanks

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Backup policies
by Ross Clement 28 Nov '07

28 Nov '07

Dear all, This is a question for people typical of "mencoder-users", rather than a question about mencoder directly. What do people on this list do in terms of backing up video. In my case my original video will be in one of three formats: Mini DV tape (and DV AVIs) - huge files, typically 13G for an hour or so. Motion JPEG from my still camera - huge files, I've used it once as a trial and got over 3G of moving images. Screen capture from PC usage - not so huge files Problem is, I don't have enough disk space to let everything just lie around. I just ran out of space on my 300G usb drive. I would like to back up all my original video in some form or other. In particular the MiniDV and Motion JPEG files are home videos that I would like to be able to review into the distant future. But burning tens of DVDs per week to avoid post-camera quality loss is really not on. At present, I generally convert things into either DVD compatible MPEG-2, or DivX of some sort. I can back these up much more recently. But it's possible for me to use pretty well any format for my backups providing that mplayer (VLC et al) can read it. What formats would people recommend, and what do others do concerning backups.

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What is wrong ?
by Luciano Marinho 28 Nov '07

28 Nov '07

Hello for all friends...i'm using mencoder to encode to VCD and SVCD to after use dvdauthor to make the other process to rip a dvd. But after run this: mencoder FILETOENCODE.avi -o FILETOENCODE.mpg -oac lavc -ovc lavc -of mpeg -mpegopts format=xvcd -vf scale=352:288,harddup -srate 44100 -af lavcresample=44100 -lavcopts vcodec=mpeg1video:keyint=15:vrc_buf_size=327:vrc_minrate=1152:vbitrate=1152:vrc_maxrate=1152:acodec=mp2:abitrate=224 -ofps 25 The dvdauthor say me that is not in dvd format. What i do wrong ? best regards!

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