Play you input movie with mplayer, ensure that mplayer plays exactly what you want to put in the DVD. In order to decide ratio and resolution you must know the resolution of your input movie. The Ntsc standard gives you two kinds of frame rate while Pal provides only one.ĭepending of the country you live in, you have to decide between Ntsc or Pal. This table shows the real resolution and how the player displays it. The codec is Mpeg-2.ĭVDs do not use square pixels, the pixels are rectangular: while the movie has a certain resolution the player has to display it as if it were deforming the pixels. The two standards also have different frame ratios. The aspect ratio can be '16/9' or '4/3', the available resolutions change if you are making a Pal or a Ntsc DVD. Standard compliant DVD videos have a well-defined and precise video requirement.
If you are changing the sampling rate and you think the audio quality is poor you can try to add the argument -af resample=48000::2: doing so mplayer will use its most precise algorithm. Using both commands, we will have two files, one per audio track.
oac lavc -lavcopts acodec=ac3:abitrate=128 -o italian_audio.ac3 Mencoder movie.mov -alang it -ovc frameno -of rawaudio -srate 48000 -channels 2 \ oac lavc -lavcopts acodec=ac3:abitrate=384 -o english_audio.ac3 Mencoder movie.mov -alang en -ovc frameno -of rawaudio -srate 48000 -channels 6 \ Usually ac3 uses 64 or 96 kbps per audio channel. If the audio track it is not an acceptable ac3 file then you have to encode it. Mencoder movie.mov -alang en -ovc frameno -of rawaudio -oac copy \ If your input file already has an ac3 encoded audio track (with an acceptable bitrate, sample rate and frame rate) you should not encode it again. Selected audio codec: afm: liba52 (AC3-liba52) In order to know your input file audio codec, you can use mplayer (of the package with the same name), here is an example of a file with a fine audio track:ĪUDIO: 48000 Hz, 6 ch, s16le, 448.0 kbit/9.72% (ratio: 56000->576000) While the heavy constraints of the video makes it almost impossible to find a video track without need of encoding, it is fairly common to find files with an ac3 track. The audio and video total bitrate cannot be greater than 9800 kbps so every audio track reduces the bitrate for the video, but it should not be a problem since a maximum of 8264 kbps (9800 - 1536) of video bitrate is enough. You can have mono, stereo or 5.1 audio tracks. A DVD video can have up to 1536 kbps of audio information, but for each audio track the limit is 448 kbps. The audio tracks are encoded using the Dolby Surround AC-3 Digital codec with a sample rate of 48000Hz. If the disk includes more than one movie, you can select one using the chapter function of the DVD player. We will begin by creating a simpleĭVD that autostarts when put in the DVD player, without any menu. 8 Appendix A: about changing frame-rateįor our purposes in this example, every movie on the DVD has one video track, at least one audio track, and possibly includes subtitles.
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