November 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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ATSC closed captioning
by David Liontooth 07 Dec '10

07 Dec '10

What is the current status of ATSC closed captioning? Way back in 2005, Scott Larsen wrote a patch to support the EIA-608 stream still present in the digital signal; was this ever merged? Is the patch still available? Cheers, Dave

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mpeg conversions
by Rick C. 02 Dec '10

02 Dec '10

Hello, I've been doing some mpeg conversion tests coming from flash like this: test.flv -ofps 30000/1001 -of mpeg -mpegopts format=mpeg2 -vf harddup -o test.mpg -oac lavc -ovc lavc -lavcopts threads=8:acodec=mp2:vcodec=mpeg2video:vbitrate=2500:keyint=15:vrc_buf_size=1835:vrc_maxrate=9800:vstrict=0 My question is I notice that if I leave out the -ofps 30000/1001 the video will not convert even if the original has a frame rate of 29.97. I'm just curious when it comes to mpeg must I specify a frame rate every time? I notice normally converting to other formats such as .mp4 it's not necessary it will just keep the existing frame rate... If I can add a related question...if I'm coming from a frame rate of let's say 29.97 and I want to go down to let's say 25 is there a way to do this without the "jumpy" appearance? Or is that the nature of lowering the frame rate? Thanks! rc

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help with "recreating indexes"
by Oliver Lu 30 Nov '10

30 Nov '10

I realize this (may be) a very simple question/problem but I have a movie it's an .avi file but it has a subtitle file (.srt) after about an hour the subtitles no longer appear, also I notice the time is no longer correct (it starts over again at zero). As per someone's suggestion about it being two files joined together (concatenated) I tried to "recreate the index" using mencoder 0.7.7 by selecting the file, going into the terminal and pasting the command mencoder input.avi -idx -ovc copy -oac copy -o output.avi however I receive the response -bash: mencoder: command not found (odd because i tried it yesterday and got a message about the audio codec, i forget what it said exactly however). Am I doing this correctly? I've never used mencoder before, I'm generally unfamiliar with CLI btw I'm on a Mac, but I have the same movie file on my hp notebook, if there's an easier way to do via Windows 7. I no longer have access to the original movie file, however. thanks to anyone who can help

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Re: [MEncoder-users] ATSC closed captioning
by Scott W. Larson 29 Nov '10

29 Nov '10

Reimar Döffinger <Reimar.Doeffinger(a)gmx.de> wrote: >Because, as I said (though I did not mention this reason) it isn't >finished yet. OK, do you have any suggestions on where I should look for the bug? For example I don't see how user data that is passed between the Sequence header code and the GOP start code will be turned into a frame by mplayer since it's not associated with a displayable frame. Generally the user data here is something that applies to all pictures in the GOP (this is where the BBC and Fox in the U.S. pass the AFD) but I have found caption data here sometimes. Another problem I'm having is if I let mplayer display captions for two hours or so, eventually it starts printing "Too many buffered pts" continuously and the video becomes choppy. Skipping backward and forward fixes it.

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demuxing question
by Rick C. 29 Nov '10

29 Nov '10

Hello, I've encountered a problem and I hope someone can help me find out what's wrong. Here's my command: test.flv -ovc lavc -lavcopts vcodec=mpeg4 -ffourcc XVID -oac faac -o test.avi The video I'm converting is 10 minutes and with a recent MEncoder build I only get about 4 minutes output. But with a MEncoder build I have from last year I get the full 10 minutes. Here is some output that might show the problem: libavformat file format detected. [lavf] Video stream found, -vid 0 [lavf] Audio stream found, -aid 1 VIDEO: [H264] 480x360 0bpp 29.917 fps 0.0 kbps ( 0.0 kbyte/s) [V] filefmt:44 fourcc:0x34363248 size:480x360 fps:29.917 ftime:=0.0334 That is from the good one and this the bad: libavformat file format detected. [flv @ 0x101857400]Estimating duration from bitrate, this may be inaccurate [lavf] stream 0: video (h264), -vid 0 [lavf] stream 1: audio (aac), -aid 0 VIDEO: [H264] 480x360 0bpp 59.750 fps 573.7 kbps (70.0 kbyte/s) [V] filefmt:44 fourcc:0x34363248 size:480x360 fps:59.750 ftime:=0.0167 And the end: Pos: 233.9s 12706f (66%) 218.85fps Trem: 0min 36mb A-V:-0.030 [736:128] Too many audio packets in the buffer: (4096 in 1584970 bytes). Maybe you are playing a non-interleaved stream/file or the codec failed? For AVI files, try to force non-interleaved mode with the -ni option. I only posted a small portion because I noticed in the good one it accurately reads 29.917fps but the bad a very different number. The rest of the output was about the same but I can post more if needed. Any idea why this might be happening or an idea of what else I can check? I honestly can't remember if I did something different compiling the MEncoder from last year. Thanks for your help! rc

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x11 error
by Rick C. 29 Nov '10

29 Nov '10

Hello again, Would anyone have an idea why I would be getting this crash: Dyld Error Message: Library not loaded: /usr/X11/lib/libfreetype.6.dylib Reason: image not found When building MEncoder I have used --disable-x11 to avoid this kind of issue. There must be something I'm missing and I appreciate the help! rc

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Re: [MEncoder-users] ATSC closed captioning
by Scott W. Larson 28 Nov '10

28 Nov '10

Reimar Döffinger <Reimar.Doeffinger(a)gmx.de> wrote: >We have three samples, two showed only half the characters, one showed >a mixture of two languages. All are working now, but it could of course >have broken something... Did you find an ATSC samples to test with? This shows that the 'CC' subtitles on DVDs are different from ATSC 'GA94' captions. Apparently the DVD captions can be displayed in frame arrival order and are just straight EIA-608 data. ATSC captions arrive out of order and need to be displayed according to the pts of the frames they came with otherwise they'll appear to be random text (generally a frame has only two to four characters of a caption). Also since ATSC captions are a mixture of CEA-608 and CEA-708 formats, you have to extract the format you want to display.

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article about converting video to DVD
by Michele Alessandrini 28 Nov '10

28 Nov '10

Hi, sorry if this seems like auto-advertising, but I finished writing an article on how to convert an arbitrary video to DVD, using MEncoder, focusing on 100% compatibility with DVD standard, to be able to play it in older, less flexible players too. In addition, many aspects related to digital video are explained, so it's not addressed to DVD only. You're welcome to read it here: http://new.linuxfocus.org/cms/?q=node/28 (first part) http://new.linuxfocus.org/cms/?q=node/29 (second part) I'm writing in the hope that someone could find it useful, because it took me much time and experiments to refine the whole process. Bye and thanks to everybody Michele Alessandrini

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