January 2008 - 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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MEncoder and DV ?
by Levente Novák 31 Jan '08

31 Jan '08

I'm forwarding this question and my answer to the list, they might interest other people as well. On Mon, 2008-01-28 at 18:28 +0000, Dieter wrote: > Hello, I'm wondering if you ever got mencoder to create DV format > output? (without core dumping and such) I used this command line last summer and it worked well (I changed my bt878-based card to a Hauppauge PVR-150 since then, and do not need to convert captures to DV anymore, so I'm uncertain if it still works): mencoder tv:// -tv driver=v4l2:device=/dev/video0:\ input=2:outfmt=uyvy:width=720:height=576:fps=25:\ audiorate=48000:forceaudio:amode=1:forcechan=2:\ brightness=6:contrast=-20 \ -vf phase=t,fil=d:d,scale,format=yv12,fil=i:i,harddup \ -of lavf -sws 0 -lavfopts format=dv -oac pcm -ovc lavc \ -lavcopts vcodec=dvvideo:top=0:ildct -o file.dv This is for PAL S-video sources. The phase inversion filter was needed since this card used to capture interlaced frames top-first in contrast to DV which is bottom-first. The magic with interlaced scaling circumvents the infamous bt8x8 chroma interlacing bug, without uyvy captures the image flickers badly around coloured areas. (BTW I do not understand why the maintainers of bt8x8 refuse to properly fix this issue known for years.) Beware that you need a fairly powerful machine to record this way in real time due to the rescaling. It could attain 25 fps on a 3.06 GHz Celeron D only with about 90% CPU load, that's why fil was substituted to il and a simple linear scaling (-sws 0) was used instead of the default one. The files this command line produced were perfectly handled by Kino. Levente

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2 movies side by side
by Cristian Baltatescu 31 Jan '08

31 Jan '08

Hi. First of all, i'm not sure if i'm asking this to the right place. Are there two separate users- lists, one for ffmpeg and one for mencoder? I tried to subscribe to both but i guess there's just one? My question is this: can you stick two movies side by side, not one after the other? Meaning, each frame of the final movie will be made of 2 frames, side by side, from two separate movies. I found a similar question in the list archives, from 2005, but no concludent answer. If the answer is yes, how can that be done? If not, i'm thinking of an alternative solution. I could, i guess make png-s of the two movies, one for each frame, somehow stick them togheter, resulting in a wider png and then making a movie out of those final png's. But i'm not sure how efficient this is from the resources (memory, disk space) point of view. And even so, i'm not sure how i could stick those 2 frames toghether as images, maybe imagemagik or somethink. Thank you!

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Video for YouTube, getting extremely low quality movies
by Apple7777 30 Jan '08

30 Jan '08

Hello, I'm trying to encode uploaded movies with highest possible quality. I'm joining two videos (logo and movie). My command line is: first pass: /usr/local/bin/mencoder -really-quiet -vf scale=448:-3,expand=448:336 -sws 9 -of lavf -ovc lavc -lavcopts vcodec=flv:vbitrate=250:trell:v4mv:mv0:mbd=2:cbp:aic:cmp=3:subcmp=3:vpass=1 -frames 800 -ofps 24000/1001 -oac mp3lame -lameopts abr:br=64:mode=0 -channels 1 -srate 22050 -of lavf -lavfopts format=flv -o /home/re/video/2/25.flv /home/re/ff/logo7.avi /home/re/video/2/27temp second pass: /usr/local/bin/mencoder -really-quiet -vf scale=448:-3,expand=448:336 -sws 9 -of lavf -ovc lavc -lavcopts vcodec=flv:vbitrate=250:trell:v4mv:mv0:mbd=2:cbp:aic:cmp=3:subcmp=3:vpass=2 -frames 800 -ofps 24000/1001 -oac mp3lame -lameopts abr:br=64:mode=0 -channels 1 -srate 22050 -of lavf -lavfopts format=flv -o /home/re/video/2/25.flv /home/re/ff/logo7.avi /home/re/video/2/27temp The output is here: http://www.roamearth.com/video/2/27.flv I wonder how can I increase quality of the output movie? I could increase bitrate little bit (maximum is 350 with sound), but when I use vbitrate=285, for example, I get movies with higher bitrates. Is there command for a hard video bitrate limit? Also, this output movie is really jerky (as the other ones) with 15 fps, and even with 24 fps! I wonder how can I fix this? Could you answer all three questions please.

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Encoding 16/9 jpegs to video
by Simon Matthews 29 Jan '08

29 Jan '08

I am trying to encode a set of 16:9 jpegs to video. This is a stop motion project. However, with all the options I try, the video is cropped -- it looks like the input is read as 4x3 and the remaining part of the frame is dropped. I am using the following command: mencoder "mf://*.jpg" -mf fps=10:type=jpeg -o /tmp/test2.avi -ovc lavc -lavcopts vcodec=msmpeg4v2:vbitrate=800:aspect=16/9 I tried adding " -aspect 16/9" into the command line but it made no difference. What should I do to get the full frame in the output video? Regards!

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Web-Form to generate mencoder line (FYI)
by Jorge Fábregas 28 Jan '08

28 Jan '08

Hello guys, I just found out about this: http://f0rked.com/projects/simplerip It's a simple web-form to generate a full mencoder line. It seems very helpful for newbies. Cheers! Jorge

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Apply filter when encoding DV avi file to xvid
by "Cédric MARCOUX (sprimont)" 27 Jan '08

27 Jan '08

Hi all! i'm using dvgrab to capture movie from my CamCorder DV I'm using mencoder to convert to xvid. I have noticed that avi created with dvgrab is good quality but when motion move I have some artifact (entrelaced line) and this not beautifull. So I was wondering if there a way to apply a filter when encoding my dv file to xvid? I have heard about yuvdenoiser but not found any documentation for using it with mencoder.... Here is my script mencoder $movie -noskip -ovc xvid -xvidencopts bitrate=-699:pass=1:min_iquant=1:max_iquant=31:min_pquant=1:max_pquant=31:min_bquant=1:max_bquant=31:nopacked:psnr:me_quality=6:quant_type=mpeg:chroma_opt:chroma_me:hq_ac:vhq=4:bvhq=1:max_bframes=3 -oac copy -ffourcc XVID -o /dev/null mencoder $movie -noskip -ovc xvid -xvidencopts bitrate=-699:pass=2:min_iquant=1:max_iquant=31:min_pquant=1:max_pquant=31:min_bquant=1:max_bquant=31:nopacked:psnr:me_quality=6:quant_type=mpeg:chroma_opt:chroma_me:hq_ac:vhq=4:bvhq=1:max_bframes=3 -oac mp3lame -lameopts mode=0:cbr:br=320 -ffourcc XVID -o converted/$movie Thanks,

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