June 2010 - 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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mencoder dvdnav:// encodes twice
by Tony Howard 05 Aug '10

05 Aug '10

Hi, I've been trying to encode encrypted DVDs using mencoder dvdnav://, and it mostly works, but it will rip the entire contents of the DVD twice to a single file... if it's a 2 hour movie, I'll end up with a 4 hour file that has the movie twice. Here's the command I've been using to rip them: mencoder dvdnav://1 -dvd-device /dev/dvd -alang English -info name="Meet The Colors" -oac copy -ovc x264 -x264encopts crf=26 -vf pp=de,crop=0:0:0:0,scale=1024:576 -o /home/video/meet_colors.avi I've seen this behavior on some (but not all) Disney DVDs, and several others as well. I'm using the rpmfuson mencoder from mencoder-1.0-0.111.20091029svn.fc12.i686.rpm on Fedora 12. Using -chapter 1-(something before the last chapter) works, but of course misses the chapters I leave out. Running mencoder dvd://1 also only encodes the movie once, but that just works for dvds that aren't encrypted. Anybody know how it to get dvdnav to only encode the movie once? Tony

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Trying to fully understand de-interlacing.
by Peter 03 Jul '10

03 Jul '10

I'm the proud owner of a Sony HX5 digital camera, which is "OK" as a "nice" camera, but has a movie mode which blows away the competition, at 1920x1080/60i which I assume means that it produces fields of 1920x540, 60 times a second, and that pairs of fields are packaged into frames at 30 frames per second. (I hope I don't have my fields and frames mixed up.) I see interlacing as a form of compression which was useful in the days of CRT screens, whereby the processing in our eyes would make us think we were seeing full resolution, full frame rate, even though only half the data rate was required. I would like to make the best of this interlaced content, without discarding either the 60 frames per second, or the 1920x1080 resolution. I want the 'impossible' holy grail of making a 1920x1080/60p file out of it. Of course, I will then compress the file with H.264, but at that point, I will let H.264 do its compression magic in a more appropriate and efficient way than the interlacing did. To let H.264 make the best file, I want it to start with the best data; so I want to know how to make yadif create the best stream: neither discarding the time data, nor the resolution data, but interpolating the missing data in time and space in the same way that our eyes do when watching an old interlaced TV. I realise that this is by no means an easy task. Stationary objects need to be interpolated spatially, and moving objects need to be interpolated temporally. Can yadif (mcdeint) do that? I have been reading with interest, the thread "A good compromise for deinterlacing camcorder-dv-files" and it looks like yadif pp=ci is the best option. Is that right? will it produce a 1920x1080/60p stream? Can anyone suggest a good command line? I have been trying to analyse Christian Ebert's suggestion of -vf yadif=1,mcdeint=2:1:10,softskip against what I take to be the manual at: http://www.mplayerhq.hu/DOCS/man/en/mplayer.1.txt and it looks like yadif produces 1920x540/60p, and then mcdeint does the interpolation with mode=2 (slow) and parity=1 (is that telling it whether it's tff or bff?) with qp set to 10. (Quality???) That manual page has no mention of pp=ci ??? -- Peter ____________________________________________________________ Publish your photos in seconds for FREE TRY IM TOOLPACK at http://www.imtoolpack.com/default.aspx?rc=if4

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[HELP] Mencoder Resize = No Subtitle
by davis right 01 Jul '10

01 Jul '10

Hi all, I hope someone can really help me here as I have been stuck for weeks and still can't find the solution with google. The subtitle for the video won't be display whenever I use the the command "-vf scale" to resize the video. Able to display subtitle but no resize: mencoder test/22.avi -o test/22.flv -of lavf -oac mp3lame -lameopts abr:br=56 -ovc lavc -lavcopts vcodec=flv:vbitrate=1000:mbd=2:mv0:trell:v4mv:cbp: last_pred=3 -srate 22050 -ofps 24 -sub test/subtitle.srt -subpos 90 -subfont-text-scale 3.5 Unable to display subtitle but resizing works: mencoder test/22.avi -o test/22.flv -of lavf -oac mp3lame -lameopts abr:br=56 -ovc lavc -lavcopts vcodec=flv:vbitrate=1000:mbd=2:mv0:trell:v4mv:cbp: last_pred=3 -srate 22050 -ofps 24 -vf scale=320:240 -sub test/subtitle.srt -subpos 90 -subfont-text-scale 3.5

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23.976 --> 25 fps conversion problem
by Tamas Selmeci 01 Jul '10

01 Jul '10

Hi all! My task is to convert any incoming .AVI video into a well-defined format: AVI container, Xvid encoder, 25 fps @ 1800 kbps video, MP3 @ 48000 Hz, 128 kbps. Everything seemed to work fine until I've received a recent movie with an fps value of 23.976. What mencoder does is just duplicating the last frame after every 24 frames, thus producing a 25 fps output file. But in case of a bit more action in the scene, the viewer will realize a small "stop" in the movie flow and it destroys the "movie experience". With the correct mixture/selection of noskip, -mc 0, etc. I was able to make mencoder not duplicating the last frame after each 24 frames, but then the A/V sync broke. Obviously, the sound was arriving much later, since a 23.976 fps video was played at 25 fps. According to Wikipedia, telecine/pullup methods are for solving these problems for the case e.g. 23.976 fps --> 30 fps. In the case of mine 25 fps is fixed, can not be changed at all. Is there any way I can produce 25 fps movie output from 23.976 fps material with frame interpolation/appropriate telecine/pullup? -vf pullup did not solve my problem. That annoying "stop" in movie flow must not be present at all. (My rescue idea is to recode video at 25 fps without frame duplication, thus the movie duration will decrease by ~4% [23.976/25], and the audio is resampled at a 4% higher frequency to keep A/V sync) Thanks in advance! -- Selmeci, Tamas http://www.open-st.eu

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hqdn3d=2:1:2 & -ovc x264
by Goga777 01 Jul '10

01 Jul '10

Hi I read somewhere that there is not any sense to use -vf hqdn3d=2:1:2 with -ovc x264 because it's useless Does it true ? Goga

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Accuracy of the -endpos option
by Josef Wolf 30 Jun '10

30 Jun '10

Hello, I have troubles with the accuracy of the -endpos option. Most of the time, I get about 40 to 50 frames too much. When I adjust the value to get the correct end position, then audio ends about 2 seconds too early. The problem doesn't seem to be dependant on the source material or the codec. I had the problem with ljpeg and DV source (which should both be searchable on a frame-by-frame bassis). Using lavc instead of x264 don' help either. Any ideas what could cause this effect?

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problem:concatenate mp4 into new one
by Pengpeng 30 Jun '10

30 Jun '10

pt@pt-laptop:~$ MP4Box -info /home/pt/sbd1.mp4 Error opening file /home/pt/sbd1.mp4: IsoMedia File is truncated pt@pt-laptop:~$ MP4Box -info /home/pt/sbd0.mp4 Error opening file /home/pt/sbd0.mp4: IsoMedia File is truncated pt@pt-laptop:~$ mp4box -info /home/pt/sbd0.mp4 mp4box: command not found pt@pt-laptop:~$ mediainfo /home/pt/sbd0.mp4 mediainfo: command not found pt@pt-laptop:~$ MP4Box -cat /home/pt/sbd0.mp4 -cat /home/pt/sbd1.mp4 -new /home/pt/sbd01.mp4 No suitable media tracks to cat in /home/pt/sbd0.mp4 - skipping Segmentation fault 1.in my computer ,can't write "mp4box -info /home/pt/sbd0.mp4" the command is "MP4Box -info /home/pt/sbd1.mp4" 2.how to concatenate them into new one?

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Creating Youtube-compliant H.264 content
by Adrian Glaubitz 29 Jun '10

29 Jun '10

Hi, I have been trying to capture some old VHS videos with a bt8x8-based analog capture card which worked nicely so far. However, when I tried to upload the video, Youtube's upload script complaint that the video I have uploaded could not be converted. I used the following command line to capture and encode with libx264 (the video has no sound, thats why I disabled it): mencoder -v -tv \ driver=v4l2:input=2:norm=PAL:alsa:adevice=hw.1,0:immediatemode=0 tv:// \ -ovc x264 -of lavf -lavfopts format=mp4 -o output.mp4 -nosound Any ideas or better tips for capturing and encoding directly into X.264? Adrian

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