December 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!

2 1

Encoding with x264 Jittery Result
by Reuben Budiardja 02 Jan '08

02 Jan '08

Hello, I am trying to use mencoder to encode VOB files with x264 codec. I'm trying to get high quality encode with 1500 kbps target bitrate and two-pass encoding. The following is what I use: mencoder CH_2.vob -ovc x264 -x264encopts subq=4:bframes=3:b_pyramid:weight_b:pass=1:psnr:bitrate=1500 -nosound -of rawvideo -o test.264 mencoder CH_2.vob -ovc x264 -x264encopts subq=6:partitions=all:8x8dct:me=umh:frameref=5:bframes=3:b_pyramid:weight_b:pass=2:psnr:bitrate=1500 -nosound -of rawvideo -o test.264 The options were basically taken from the example in Mplayer documentation, with the fast, low quality setting for the first pass and high-quality for the second pass. The result is a very jittery movie. I checked that after the first pass the result is still OK, but after the second pass it's very jittery. Is there something that I did that's obviously wrong ? Although I glanced through the manual, I admit I don't really understand all the options (it's kinda overwhelming). Is there any recipe to get high quality two-pass encoding with 1500kbps bitrate ? I eventually wants to mux the sound (AC3) and subtitle in mastroska container. Thank you for any help. RDB

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Recoding RM files for iPod
by Ulf Magnusson 02 Jan '08

02 Jan '08

Hi, I've been trying for a couple of days to recode RM files for viewing on my iPod. Afters some initial research I came up with the following: $ mencoder movie.rm -o ipod.mp4 \ -of lavf -lavfopts format=mp4 \ -ovc x264 -x264encopts qp=20:keyint=60 \ -oac faac -faacopts mpeg=4:raw:object=2:br=160 \ -srate 48000 \ -vf scale=320:240 This produces a file that plays fine in MPlayer, but gives a white screen with just sound in QuickTime. iTunes refuses to transfer the file to the iPod, saying "ipod.mp4 was not copied to the iPod <foo> because it cannot be played on this iPod". For the above, MEncode prints the following warning: ** MUXER_LAVF ***************************************************************** REMEMBER: MEncoder's libavformat muxing is presently broken and can generate INCORRECT files in the presence of B frames. Moreover, due to bugs MPlayer will play these INCORRECT files as if nothing were wrong! ******************************************************************************* I thought I'd instead try doing the muxing with MP4Box, using the following (inspired by the script from http://diveintomark.org/archives/2007/06/07/howto-batch-encode-video-for-ip…) $ mencoder movie.rm -o ipod.avi \ -ovc x264 -x264encopts qp=20:keyint=60 \ -oac faac -faacopts mpeg=4:object=2:br=160:raw \ -srate 48000 \ -vf scale=320:240 $ MP4Box -aviraw video ipod.avi $ MP4Box -aviraw audio ipod.avi $ mv ipod_audio.raw ipod.aac $ mv ipod_video.h264 ipod.h264 $ MP4Box -add ipod.aac:lang=en ipod.mp4 $ MP4Box -add ipod.h264:fps=23.976 ipod.mp4 This gives a file that won't play at all in QuickTime ("An invalid sample description was found in the movie."), and that iTunes still refuses to copy to the iPod. It still plays in MPlayer, but without any sound, and with the following errors: FAAD: Failed to decode frame: Invalid number of channels FAAD: Failed to decode frame: Maximum number of bitstream elements exceeded FAAD: Failed to decode frame: Unexpected channel configuration change FAAD: Failed to decode frame: Unexpected channel configuration change The file I'm trying to recode is http://ocw.mit.edu/ans7870/6/6.046j/f05/lecturenotes/ocw-6.046-07sep2005-22… . I'm running out of ideas. Any help appreciated! /Ulf

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AC3 and Strange Video Playback
by Nigel Arnold 01 Jan '08

01 Jan '08

Hello I'm getting a problem creating any MPEG4 AVI with any AC3 audio track. I've tried RC2 and also a 25088 build as provided by Sherypa I''ve stripped back to a very basic bare command line, mencoder dvd://1 -dvd-device R:\ -oac lavc -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=1024:acodec=ac3:abitrate=192 -ofps 24000/1001 -Chapter 03-03 -o "AC3 Test.avi" The resulting .avi file - 1. The video plays about 2-3 times faster than speed than normal (like a Fast forward) in VLC, and WMP 2. The video is not seekable, as soon as I position in VLC, the video ends, in WMP If i seek, the video stops, audio still plays and takes about 10 minutes for the video / audio to start playing again. This appears to be only related to AC3, as if I choose libmp3lame or libfaac, the video's are fine. I've tried the above command with a much earlier build 21190 and it works fine. the resulting video file plays fine in VLC, WMP and MPlayer Any Ideas Thx in advance N

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Re: [MEncoder-users] stop/restart mencoder
by TAJTHY Tamás 31 Dec '07

31 Dec '07

Dear RC, THX for your help! 2007. 12. 28. p. 14:44, RC <cooleyr(a)gmail.com> írta: >On Fri, 28 Dec 2007 14:13:46 +0100 >TAJTHY Tamas tajthy(a)mailbox.hu> wrote: > >> I can use the ctrl+S, but I don't know how to restart automatically (I >> can continue pressing ctrl+Q, but it is manual :-( ). > >> Does anybody know a way to stop and continue mencoder automatically? >> The stop can remain manual... > >You can use Ctrl+Z to suspend the task, then do something like ># command && fg Unfortunatelly ctrl+Z is not working under cygwin either. :-( If I start X then ctrl+Z send mencoder as a background process but it is still running!?! >Since you're running under Windows, you should probably be using the >Windows tools, like setting the process priority to idle. I think You mean the low priority. Cygwin has also "nice/renice" implemented, so I can set/change priority. I tried to play with it, but without luck. :-( >I really can't imagine why you would need this. Whatever the problem, >there's no doubt a better way to solve it. I try to descripe in few words: I capture filmes by VirtualDub and the ffmjpeg'd avi is compressed to mpeg4 by mencoder. If the capture is 2 hours, the 1st pass of mencoder is 2.5 hours, the 2nd pass is cca 6 hours. Sometimes it would be nice if I could capture an other film during the mencoder compression. I tried to change the mencoder's priority to idle (20), but it allows me only to set to 19 (low. It seems to me low = idle. Is it true?). I set the priority of VirtualDub to AboveNormal or High, but there were still some audio and video desynchronisation. If I stopped mencoder by ctrl+S, it becomes okay, but I can not restart it automatically after... Maybe I will try to find a sendkey program... THX && Good byte! TT _____________________________________________________________________ Rövid angol nyelvlecke következik. Elektronikus postafiók/postaláda - Mailbox www.mailbox.hu

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stop/restart mencoder
by TAJTHY Tamás 28 Dec '07

28 Dec '07

Hi, I use mencoder under cygwin. Is there a way to stop mencoder and restart it? I tried the "kill -STOP", but it does not work with cygwin. I can use the ctrl+S, but I don't know how to restart automatically (I can continue pressing ctrl+Q, but it is manual :-( ). Or even I can kill mencoder and restart only the cancelled pass, but it is a pure waste of time. Does anybody know a way to stop and continue mencoder automatically? The stop can remain manual... I have only one idea right now. I write an extended "cat" which check periodically a file (or a signal). If the file exists (or signal caught), it stops sending data to the stdout. I think I should use sg like this: xcat file.avi | mencoder opts - Is there no better way??? TIA && Good byte! TT _____________________________________________________________A legnagyobb TORRENT kereső napi 25000 új letöltés - www.warez.hu

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Mencoder with multiple processors
by . . 27 Dec '07

27 Dec '07

Hi, Can Mencoder use two processors for encoding? Thanks. K.

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