Encoding with <application>MEncoder</application>

Encoding with <application>MEncoder</application> For the complete list of available MEncoder options and examples, please see the man page. For a series of hands-on examples and detailed guides on using several encoding parameters, read the encoding-tips that were collected from several mailing list threads on mplayer-users. Search the archives for a wealth of discussions about all aspects of and problems related to encoding with MEncoder. Encoding 2-pass MPEG4 ("DivX") The name comes from the fact that this method encodes the file twice. The first encoding (dubbed pass) creates some temporary files (*.log) with a size of few megabytes, do not delete them yet (you can delete the AVI). In the second pass, the 2-pass output file is created, using the bitrate data from the temporary files. The resulting file will have much better image quality. If this is the first time you heard about this, you should consult some guides available on the net. copy audio track 2-pass encode of a DVD to an MPEG4 ("DivX") AVI while copying the audio track. mencoder dvd://2 -ovc lavc -lavcopts vcodec=mpeg4:vpass=1 -oac copy -o movie.avi mencoder dvd://2 -ovc lavc -lavcopts vcodec=mpeg4:vpass=2 -oac copy -o movie.avi encode audio track 2-pass encode of a DVD to an MPEG4 ("DivX") AVI while encoding the audio track to MP3. mencoder dvd://2 -ovc lavc -lavcopts vcodec=mpeg4:vpass=1 -oac mp3lame -lameopts vbr=3 -o movie.avi mencoder dvd://2 -ovc lavc -lavcopts vcodec=mpeg4:vpass=2 -oac mp3lame -lameopts vbr=3 -o movie.avi Encoding to MPEG format MEncoder can create MPEG (MPEG-PS) format output files. It's probably useful only with libavcodec's mpeg1video codec, because players - except MPlayer - expect MPEG1 video, and MPEG1 layer 2 (MP2) audio streams in MPEG files. This feature is not very useful right now, aside that it probably has many bugs, but the more importantly because MEncoder currently cannot encode MPEG1 layer 2 (MP2) audio, which all other players expect in MPEG files. To change MEncoder's output file format, use the option. Example: mencoder -of mpeg -ovc lavc -lavcopts vcodec=mpeg1video -oac copy other_options media.avi -o output.mpg Rescaling movies Often the need to resize movie images' size emerges. Its reasons can be many: decreasing file size, network bandwidth,etc. Most people even do rescaling when converting DVDs or SVCDs to DivX AVI. If you wish to rescale, read the Preserving aspect ratio section. The scaling process is handled by the scale video filter: . Its quality can be set with the option. If it's not specified, MEncoder will use 0: fast bilinear. Usage: mencoder input.mpg -ovc lavc -lavcopts vcodec=mpeg4 -vf scale=640:480 -o output.avi Stream copying MEncoder can handle input streams in two ways: encode or copy them. This section is about copying. Video stream (option ): nice stuff can be done :) Like, putting (not converting!) FLI or VIVO or MPEG1 video into an AVI file! Of course only MPlayer can play such files :) And it probably has no real life value at all. Rationally: video stream copying can be useful for example when only the audio stream has to be encoded (like, uncompressed PCM to MP3). Audio stream (option ): straightforward. It is possible to take an external audio file (MP3, WAV) and mux it into the output stream. Use the option for this. Fixing AVIs with broken index or interleaving Easiest thing. We simply copy the video and audio streams, and MEncoder generates the index. Of course this cannot fix possible bugs in the video and/or audio streams. It also fixes files with broken interleaving, thus the option won't be needed for them anymore. Command: mencoder -idx input.avi -ovc copy -oac copy -o output.avi Appending multiple AVI files As a side-effect, the broken AVI fixer function enables MEncoder to append 2 (or more) AVI files: Command: cat 1.avi 2.avi > 3.avi mencoder -noidx -ovc copy -oac copy -o output.avi 3.avi This expects 1.avi and 2.avi to use the same codecs, resolution, stream rate etc, and at least 1.avi must not be broken. You may need to fix your input AVI files first, as described above. Encoding with the <systemitem class="library">libavcodec</systemitem> codec family libavcodec provides simple encoding to a lot of interesting video and audio formats. You can encode to the following codecs (more or less up to date): Codec nameDescription mjpeg Motion JPEG ljpeg Lossless JPEG h263 H263 h263p H263 Plus mpeg4 ISO standard MPEG4 (DivX 5, XVID compatible) msmpeg4 pre-standard MPEG4 variant by MS, v3 (aka DivX3) msmpeg4v2 pre-standard MPEG4 by MS, v2 (used in old asf files) wmv1 Windows Media Video, version 1 (aka WMV7) wmv2 Windows Media Video, version 2 (aka WMV8) rv10 an old RealVideo codec mpeg1video MPEG1 video mpeg2video MPEG2 video huffyuv lossless compression asv1 ASUS Video v1 asv2 ASUS Video v2 ffv1 FFmpeg's lossless video codec The first column contains the codec names that should be passed after the vcodec config, like: An example, with MJPEG compression: mencoder dvd://2 -o title2.avi -ovc lavc -lavcopts vcodec=mjpeg -oac copy Encoding from multiple input image files (JPEG, PNG, TGA, SGI) MEncoder is capable of creating movies from one or more JPEG, PNG or TGA files. With simple framecopy it can create MJPEG (Motion JPEG), MPNG (Motion PNG) or MTGA (Motion TGA) files. Explanation of the process: MEncoder decodes the input image(s) with libjpeg (when decoding PNGs, it will use libpng). MEncoder then feeds the decoded image to the chosen video compressor (DivX4, XviD, FFmpeg msmpeg4, etc.). Examples The explanation of the option is in the man page. Creating an MPEG4 file from all the JPEG files in the current directory: mencoder mf://*.jpg -mf type=jpg:w=800:h=600:fps=25 -ovc lavc -lavcopts vcodec=mpeg4 -oac copy -o output.avi Creating an MPEG4 file from some JPEG files in the current directory: mencoder mf://frame001.jpg,frame002.jpg -mf type=jpg:w=800:h=600:fps=25 -ovc lavc -lavcopts vcodec=mpeg4 -oac copy -o output.avi Creating a Motion JPEG (MJPEG) file from all the JPEG files in the current directory: mencoder mf://*.jpg -mf type=jpg:w=800:h=600:fps=25 -ovc copy -oac copy -o output.avi Creating an uncompressed file from all the PNG files in the current directory: mencoder mf:// -mf w=800:h=600:fps=25:type=png -ovc raw -oac copy -o output.avi Width must be integer multiple of 4, it's a limitation of the RAW RGB AVI format. Creating a Motion PNG (MPNG) file from all the PNG files in the current directory: mencoder mf://*.jpg -mf w=800:h=600:fps=25:type=png -ovc copy -oac copy -o output.avi Creating a Motion TGA (MTGA) file from all the TGA files in the current directory: mencoder mf://*.tga -mf w=800:h=600:fps=25:type=tga -ovc copy -oac copy -o output.avi Extracting DVD subtitles to VOBsub file MEncoder is capable of extracting subtitles from a DVD into VOBsub formatted files. They consist of a pair of files ending in .idx and .sub and are usually packaged in a single .rar archive. MPlayer can play these with the and options. You specify the basename (i.e without the .idx or .sub extension) of the output files with and the index for this subtitle in the resulting files with . If the input is not from a DVD you should use to indicate the .ifo file needed to construct the resulting .idx file. If the input is not from a DVD and you do not have the .ifo file you will need to use the option to let it know what language id to put in the .idx file. Each run will append the running subtitle if the .idx and .sub files already exist. So you should remove any before starting. Copying two subtitles from a DVD while doing 3-pass encoding rm subtitles.idx subtitles.sub mencoder dvd://1 -vobsubout subtitles -vobsuboutindex 0 -sid 2 -o frameno.avi -ovc frameno mencoder dvd://1 -oac copy -ovc lavc -lavcopts vcodec=mpeg4:vpass=1 mencoder dvd://1 -oac copy -ovc lavc -lavcopts vcodec=mpeg4:vpass=2 -vobsubout subtitles -vobsuboutindex 1 -sid 5 Copying a french subtitle from an MPEG file rm subtitles.idx subtitles.sub mencoder movie.mpg -ifo movie.ifo -vobsubout subtitles -vobsuboutindex 0 -vobsuboutid fr -sid 1 Preserving aspect ratio DVDs and SVCDs (i.e. MPEG1/2) files contain an aspect ratio value, which describes how the player should scale the video stream, so humans won't have egg heads (ex.: 480x480 + 4:3 = 640x480). However when encoding to AVI (DivX) files, you have be aware that AVI headers don't store this value. Rescaling the movie is disgusting and time consuming, there has to be a better way! There is MPEG4 has an unique feature: the video stream can contain its needed aspect ratio. Yes, just like MPEG1/2 (DVD, SVCD) and H263 files. Regretfully, there are no video players outside which support this attribute of MPEG4, except MPlayer. This feature can be used only with libavcodec's mpeg4 codec. Keep in mind: although MPlayer will correctly play the created file, other players will use the wrong aspect ratio. You seriously should crop the black bands over and below the movie image. See the man page for the usage of the cropdetect and crop filters. Usage mencoder sample-svcd.mpg -ovc lavc -lavcopts vcodec=mpeg4:autoaspect -vf crop=714:548:0:14 -oac copy -o output.avi Custom inter/intra matrices With this feature of libavcodec you are able to set custom inter (I-frames/key frames) and intra (P-frames/predicted frames) matrices. It is supported by many of the codecs: mpeg1video and mpeg2video are reported as working. A typical usage of this feature is to set the matrices preferred by the KVCD specifications. The KVCD "Notch" Quantization Matrix: Intra: 8 9 12 22 26 27 29 34 9 10 14 26 27 29 34 37 12 14 18 27 29 34 37 38 22 26 27 31 36 37 38 40 26 27 29 36 39 38 40 48 27 29 34 37 38 40 48 58 29 34 37 38 40 48 58 69 34 37 38 40 48 58 69 79 Inter: 16 18 20 22 24 26 28 30 18 20 22 24 26 28 30 32 20 22 24 26 28 30 32 34 22 24 26 30 32 32 34 36 24 26 28 32 34 34 36 38 26 28 30 32 34 36 38 40 28 30 32 34 36 38 42 42 30 32 34 36 38 40 42 44 Usage: $ mencoder input.avi -o output.avi -oac copy -ovc lavc -lavcopts inter_matrix=...:intra_matrix=... $ mencoder input.avi -ovc lavc -lavcopts vcodec=mpeg2video:intra_matrix=8,9,12,22,26,27,29,34,9,10,14,26,27,29,34,37, 12,14,18,27,29,34,37,38,22,26,27,31,36,37,38,40,26,27,29,36,39,38,40,48,27, 29,34,37,38,40,48,58,29,34,37,38,40,48,58,69,34,37,38,40,48,58,69,79 :inter_matrix=16,18,20,22,24,26,28,30,18,20,22,24,26,28,30,32,20,22,24,26, 28,30,32,34,22,24,26,30,32,32,34,36,24,26,28,32,34,34,36,38,26,28,30,32,34, 36,38,40,28,30,32,34,36,38,42,42,30,32,34,36,38,40,42,44 -oac copy -o svcd.mpg Making a high quality MPEG4 ("DivX") rip of a DVD movie Ripping a DVD title into a maximally high quality MPEG4 (DivX) file involves many considerations. Below is an example of the process when there is no file size goal (other than perhaps fitting the result into 2GB). libavcodec will be used for the video, and the audio will be copied as is without any changes. Cropping Play the DVD and run the crop detection filter () on it. This gives you a crop rectangle to use for encoding. The reason for cropping is that many movies are not shot in a standard DVD aspect ratio (16/9 or 4/3), or, for whatever reason, the picture does not properly fill the frame. So you want to crop out the pointless black bars when you rip. It also improves the quality of the rip since the sharp edge of the black bars wastes a lot of bits. A common aspect is 2.35, which is cinescope. Most big blockbuster movies have this aspect ratio. Quality level Next you need to choose the desired quality level. When there is no need to fit the resulting file on CDs or the like, using constant quantizing AKA constant quality is a good choice. That way each frame is given as much bits as its needs to keep the quality at the desired level, but multiple encoding passes are not needed. With libavcodec, you get constant quality by using . should give you a file below 2GB in size, depending mainly on the movie length and video noisiness (the more noise, the harder it is to compress). Files over 2GB If the file resulting from constant quality encoding is over 2GB big, you will have to create an index to be able to view it properly. Either play the file with to create an index on the fly or use to write an index to a file once and to use it when playing the file. If this bothers you, you may want to keep the file size below 2GB. There are three ways to avoid this. You can try encoding again using and see if both the resulting file size and picture quality are acceptable. You can also use 2 pass encoding. As you will be copying the audio track as is and hence know its bitrate, and you know the running time of the movie, you can compute the required video bitrate to give to the option without using 3 pass encoding. The third and possibly the best option may be to slightly scale down the resolution. The uniform slight softening and loss of detail is visually more appealing than the blockiness and other artifacts caused by MPEG compression. Scaling down also effectively reduces the noise of the picture, which is good, as noise is hard to compress. Deinterlacing If the movie is interlaced, you may want to deinterlace it as part of the ripping. It is debatable whether deinterlacing should be done at this stage. The benefit is that deinterlacing when converting to MPEG4 makes compression better, and viewing easier and less CPU intensive on computer monitors as no deinterlacing is required at that stage. If deinterlacing at the ripping stage is a good idea depends on the DVD. If the DVD is made from film, which was shot at 24 fps, you can as well deinterlace while ripping. If, however, the original was 50/60 fps video, converting into deinterlaced 23.976/25 fps video will lose information. If you do decide to deinterlace, you can further experiment with different deinterlacing filters. See http://www.wieser-web.de/MPlayer/ for examples. A good starting point is . If you are both cropping and deinterlacing, deinterlace before cropping. Actually, this is not necessary if the crop offset is vertically a multiple of 2 pixels. However with some other filters, like dering, you should always crop last, so it's a good habit to put the crop filter last. Inverse telecine If you are ripping a PAL DVD, which is 25 fps, you do not need to think about the fps. Just use 25 fps. NTSC DVDs on the other hand are 29.97 fps (often rounded to 30 fps, but that is not what they are). If the movie was shot for TV, you again do not need to touch the fps. But if the movie was shot on film, and hence at (exactly) 24 fps, it has been converted to 29.97 fps when making the DVD. That conversion where 12 fields are added to each 24 frames of film is called telecine. For more info about telecine, see a Google search for "telecine field 23.976". In case you have such a telecined DVD, you will want to do inverse telecine, that is convert the movie to 23.976 fps (29.97*4/5). Otherwise camera panning will look jerky and awful. You can use for this. Anything that is shown in theatres is shot on film and needs inverse telecine, TV shows do not. Scaling and aspect ratio For best quality, do not scale the movie while ripping. Scaling down obviously loses detail, and scaling up causes artifacts and obviously makes the file larger. Pixels in DVD movies are not square, so DVD movies include info about the correct aspect ratio. It is possible to store the aspect ratio in the MPEG4 header of the output file. Most video players ignore this info, but MPlayer honors it. So if you are only going to use MPlayer for viewing the ripped file, you do not need to scale the movie, just pass to MEncoder and things will automagically work right. If you must scale the movie, be careful about getting the size right especially if you do cropping. Summing it up With all of the above mentioned in mind, a suitable encoding command might be mencoder dvd://1 -aid 128 -oac copy -ovc lavc -lavcopts vcodec=mpeg4:vqscale=3:vhq:v4mv:trell:autoaspect \ -ofps 23.976 -vf crop=720:364:0:56 -o Harry_Potter_2.avi Here gives the DVD title to rip. Option says to use audio track 128, and to copy it as is. You'll have to use MPlayer to find out the right values for these options. Options for improve quality versus bitrate, but make encoding take longer. Especially slows encoding down but also increases quality visibly. If you want to deinterlace, add a filter to , for example (in that order). If you don't need inverse telecine, leave out the . How to deal with telecine and interlacing within NTSC DVDs Introduction I suggest you visit this page if you don't understand much of what is written in this document: http://www.divx.com/support/guides/guide.php?gid=10 This URL links to an understandable and reasonably comprehensive description of what telecine is. For technical reasons pertaining to the limitations of early television hardware, all video intended to be displayed on an NTSC television set must be 59.94 fields per second. Made-for-TV movies and shows are often filmed directly at 59.94 fields per second, but the majority of cinema is filmed at 24 or 23.976 frames per second. When cinematic movie DVDs are mastered, the video is then converted for television using a process called telecine. On a DVD, the video is never actually stored as 59.94 fields per second. For video that was originally 59.94, each pair of fields is combined to form a frame, resulting in 29.97 frames per second. Hardware DVD players then read a flag embedded in the video stream to determine whether the odd- or even-numbered lines should form the first field. Usually, 23.976 frames per second content stays as it is when encoded for a DVD, and the DVD player must perform telecining on-the-fly. Sometimes, however, the video is telecined before being stored on the DVD; even though it was originally 23.976 frames per second, it becomes 59.94 fields per second, and is stored on the disk as 29.97 frames per second. When looking at individual frames formed from 59.94 fields per second video, telecined or otherwise, interlacing is clearly visible wherever there is any motion, because one field (say, the even-numbered lines) represents a moment in time 1/59.94th of a second later than the other. Playing interlaced video on a computer looks ugly both because the monitor is higher resolution and because the video is shown frame-after-frame instead of field-after-field. Notes: This section only applies to NTSC DVDs, and not PAL. The example MEncoder lines throughout the document are not intended for actual use. They are simply the bare minimum required to encode the pertaining video category. How to make good DVD rips or fine-tune libavcodec for maximum quality is not within the scope of this document. There are a couple footnotes specific to this guide, linked like this: [1] How to tell what type of video you have Progressive Progressive video was originally filmed at 23.976 fps, and stored on the DVD without alteration. When you play a progressive DVD in MPlayer, MPlayer will print the following line as soon as the movie begins to play: demux_mpg: 24fps progressive NTSC content detected, switching framerate. From this point forward, demux_mpg should never say it finds "30fps NTSC content." When you watch progressive video, you should never see any interlacing. Beware, however, because sometimes there is a tiny bit of telecine mixed in, where you wouldn't expect. I've encountered TV show DVDs that have one second of telecine at every scene change, or at seemingly random places. I once watched a DVD that had a progressive first half, and the second half was telecined. If you want to be really thorough, you can scan the entire movie: mplayer dvd://1 -nosound -vo null -benchmark Using makes MPlayer play the movie as quickly as it possibly can; still, depending on your hardware, it can take a while. Every time demux_mpg reports a framerate change, the line immediately above will show you the time at which the change occurred. Sometimes progressive video is referred to as "soft-telecine" because it is intended to be telecined by the DVD player. Telecined Telecined video was originally filmed at 23.976, but was telecined before it was written to the DVD. MPlayer does not (ever) report any framerate changes when it plays telecined video. Watching a telecined video, you will see interlacing artifacts that seem to "blink": they repeatedly appear and disappear. You can look closely at this by mplayer dvd://1 -speed 0.1 Seek to a part with motion. Look at the pattern of interlaced-looking and progressive-looking frames. If the pattern you see is PPPII,PPPII,PPPII,... then the video is telecined. If you see some other pattern, then the video may have been telecined using some non-standard method and MEncoder cannot losslessly convert it to progressive. If you don't see any pattern at all, then it is most likely interlaced. Sometimes telecined video is referred to as "hard-telecine". Interlaced Interlaced video was originally filmed at 59.94 fields per second, and stored on the DVD as 29.97 frames per second. The interlacing is a result of combining pairs of fields into frames, because within each frame, each field is 1/59.94 seconds apart. As with telecined video, MPlayer should not ever report any framerate changes when playing interlaced content. When you view an interlaced video closely with , you will see that every single frame is interlaced. Mixed progressive and telecine All of a "mixed progressive and telecine" video was originally 23.976 frames per second, but some parts of it ended up being telecined. When MPlayer plays this category, it will (often repeatedly) switch back and forth between "30fps NTSC" and "24fps progressive NTSC". Watch the bottom of MPlayer's output to see these messages. You should check the "30fps NTSC" sections to make sure they are actually telecine, and not just interlaced. Mixed progressive and interlaced In "mixed progressive and interlaced" content, progressive and interlaced video have been spliced together. This category looks just like "mixed progressive and telecine", until you examine the 30fps sections and see that they don't have the telecine pattern. How to encode each category As I mentioned in the beginning, example MEncoder lines below are not meant to actually be used; they only demonstrate the minimum parameters to properly encode each category. Progressive Progressive video requires no special filtering to encode. The only parameter you need to be sure to use is . Otherwise, MEncoder will try to encode at 29.97 fps and duplicate frames. mencoder dvd://1 -nosound -ovc lavc -ofps 23.976 Telecined Telecine can be reversed to retrieve the original 23.976 content, using a process called inverse-telecine. MPlayer contains two filters to accomplish this: and . You can read the manual page to see their differences, but for DVDs I've never had a problem with . Note that you should always inverse-telecine before any rescaling; unless you really know what you're doing, inverse-telecine before cropping, too [1]. Again, is needed, too. mencoder dvd://1 -nosound -vf ivtc=1 -ovc lavc -ofps 23.976 Interlaced For most practical cases it is not possible to retrieve a complete progressive video from interlaced content. The only way to do so without losing half of the vertical resolution is to double the framerate and try to "guess" what ought to make up the corresponding lines for each field (this has drawbacks - see method 3). Encode the video in interlaced form. Normally, interlacing wreaks havoc with the encoder's ability to compress well, but libavcodec has two parameters specifically for dealing with storing interlaced video a bit better: and . Also, using is strongly recommended [2] because it will encode macroblocks as non-interlaced in places where there is no motion. Note that is NOT needed here. mencoder dvd://1 -nosound -ovc lavc -lavcopts ildct:ilme:mbd=2 Use a deinterlacing filter before encoding. There are several of these filters available to choose from, each with its own advantages and disadvantages. Consult to see what's available (grep for "deint"), and search the MPlayer mailing lists to find many discussions about the various filters. Again, the framerate is not changing, so no . Also, deinterlacing should be done after cropping [1] and before scaling. mencoder dvd://1 -nosound -vf pp=lb -ovc lavc Unfortunately, this option is buggy with MEncoder; it ought to work well with MEncoder G2, but that isn't here yet. You might experience crahes. Anyway, the purpose of is to create a full frame out of each field, which makes the framerate 59.94. The advantage of this approach is that no data is ever lost; however, since each frame comes from only one field, the missing lines have to be interpolated somehow. There are no very good methods of generating the missing data, and so the result will look a bit similar to when using some deinterlacing filters. Generating the missing lines creates other issues, as well, simply because the amount of data doubles. So, higher encoding bitrates are required to maintain quality, and more CPU power is used for both encoding and decoding. tfields has several different options for how to create the missing lines of each frame. If you use this method, then Reference the manual, and chose whichever option looks best for your material. Note that when using you have to specify both and to be twice the framerate of your original source. mencoder dvd://1 -nosound -vf tfields=2 -ovc lavc -fps 59.94 -ofps 59.94 If you plan on downscaling dramatically, you can excise and encode only one of the two fields. Of course, you'll lose half the vertical resolution, but if you plan on downscaling to at most 1/2 of the original, the loss won't matter much. The result will be a progressive 29.97 frames per second file. The procedure is to use , then crop [1] and scale appropriately. Remember that you'll have to adjust the scale to compensate for the vertical resolution being halved. mencoder dvd://1 -nosound -vf field=0 -ovc lavc Mixed progressive and telecine In order to turn mixed progressive and telecine video into entirely progressive video, the telecined parts have to be inverse-telecined. There are two filters that accomplish this natively, but a better solution most of the time is to use two filters in conjunction (read onward for more detail). Currently the most reliable method to deal with this type of video is to, rather than inverse-telecine the telecined parts, telecine the non-telecined parts and then inverse-telecine the whole video. Sound confusing? softpulldown is a filter that goes through a video and makes the entire file telecined. If we follow softpulldown with either or , the final result will be entirely progressive. Cropping and scaling should be done after the inverse-telecine operations, and is needed. mencoder dvd://1 -nosound -vf softpulldown,ivtc=1 -ovc lavc -ofps 23.976 is designed to inverse-telecine telecined material while leaving progressive data alone. Pullup doesn't really work well with the current MEncoder, though, and is really intended for use with MEncoder G2 (whenever it's ready). It works fine without , but is needed to prevent choppy output. With , it sometimes fails. The problems arise from MEncoder's behavior of dropping frames to maintain synchronization between the audio and video: it drops frames before sending them through the filter chain, rather than after. As a result, is sometimes deprived of the data it needs. If MEncoder drops too many frames in a row, it starves 's buffers and causes it to crash. Even if MEncoder only drops one frame, still doesn't get to see it, and will end up operating on an incorrect sequence of frames. Even though this doesn't cause a crash, won't be able to make correct decisions on how to reassemble progressive frames, and will either match fields together incorrectly or drop several fields to compensate. I haven't used myself, but here's what D Richard Felker III has to say:

It's OK, but IMO it tries to deinterlace rather than doing inverse telecine too often (much like settop DVD players & progressive TVs) which gives ugly flickering and other artefacts. If you're going to use it, you at least need to spend some time tuning the options and watching the output first to make sure it's not messing up.

Mixed progressive and interlaced There are two options for dealing with this category, each of which is a compromise. You should decide based on the duration/location of each type. Treat it as progressive. The interlaced parts will look interlaced, and some of the interlaced fields will have to be dropped, resulting in a bit of uneven jumpiness. You can use a postprocessing filter if you want to, but it may slightly degrade the progressive parts. This option should definitely not be used if you want to eventually display the video on an interlaced device (with a TV card, for example). If you have interlaced frames in a 23.976 frames per second video, they will be telecined along with the progressive frames. Half of the interlaced "frames" will be displayed for three fields' duration (3/59.94 seconds), resulting in a flicking "jump back in time" effect that looks quite bad. If you even attempt this, you must use a deinterlacing filter like or . It may also be a bad idea for progressive display, too. It will drop pairs of consecutive interlaced fields, resulting in a discontinuity that can be more visible than with the second method, which shows some progressive frames twice. 29.97 frames per second interlaced video is already a bit choppy because it really should be shown at 59.94 fields per second, so the duplicate frames don't stand out as much. Either way, it's best to consider your content and how you intend to display it. If your video is 90% progressive and you never intend to show it on a TV, you should favor a progressive approach. If it's only half progressive, you probably want to encode it as if it's all interlaced. Treat it as interlaced. Some frames of the progressive parts will need to be duplicated, resulting in uneven jumpiness. Again, deinterlacing filters may slightly degrade the progressive parts. Footnotes About cropping: Video data on DVDs are stored in a format called YUV 4:2:0. In YUV video, luma ("brightness") and chroma ("color") are stored separately. Because the human eye is somewhat less sensitive to color than it is to brightness, in a YUV 4:2:0 picture there is only one chroma pixel for every four luma pixels. In a progressive picture, each square of four luma pixels (two on each side) has one common chroma pixel. You must crop progressive YUV 4:2:0 to even resolutions, and use even offsets. For example, is OK but is not. When you are dealing with interlaced YUV 4:2:0, the situation is a bit more complicated. Instead of every four luma pixels in the frame sharing a chroma pixel, every four luma pixels in each field share a chroma pixel. When fields are interlaced to form a frame, each scanline is one pixel high. Now, instead of all four luma pixels being in a square, there are two pixels side-by-side, and the other two pixels are side-by-side two scanlines down. The two luma pixels in the intermediate scanline are from the other field, and so share a different chroma pixel with two luma pixels two scanlines away. All this confusion makes it necessary to have vertical crop dimensions and offsets be multiples of four. Horizontal can stay even. For telecined video, I recommend that cropping take place after inverse telecining. Once the video is progressive you only need to crop by even numbers. If you really want to gain the slight speedup that cropping first may offer, you must crop vertically by multiples of four or else the inverse-telecine filter won't have proper data. For interlaced (not telecined) video, you must always crop vertically by multiples of four unless you use before cropping. About encoding parameters and quality: Just because I recommend here doesn't mean it shouldn't be used elsewhere. Along with , is one of the two libavcodec options that increases quality the most, and you should always use at least those two unless the drop in encoding speed is prohibitive (e.g. realtime encoding). There are many other options to libavcodec that increase encoding quality (and decrease encoding speed) but that is beyond the scope of this document.