The video tab allows to customize the video encoding parameters.
The video codec pulldown menu sets the encoding engine and the target format of your converted file. For each choice, the label indicates the choosen file format (eg. MPEG4), the corresponding file container format and filename extension (eg. AVI) and the encoding engine being used (eg. mencoder). The following choices are currently available:
This is the codec known as "libavcodec mpeg-4". Compatible with DivX 4 and DivX 5 players and introduced by the ffmpeg open-source project, it's an incredibly fast encoding engine, now Altivec optimized, and also one of the highest quality MPEG-4 codecs around, constantly improved. Use it when speed is your first choice.
This is the same "libavcodec mpeg-4" codec as above but driven by the mencoder software, which adds features like advanced encoding options, better video/audio sync for NTSC material, filters, subtitles and autocrop. It is significantly slower than the ffmpeg engine. Use it when you need these advanced features and when quality is your first choice. Note: AVI 1.0 format has a maximum file size of 2GB.
The XviD codec is currently the better looking mpeg-4 codec on all platforms. Note: AVI 1.0 format has a maximum file size of 2GB.
This is "libavcodec" implementation of DivX 3. It's clearly outweighed in quality by the preceding codecs. Use it when you must read the converted file on a DivX 3-only player.
Same as preceding, but with mencoder features of better video/audio sync for NTSC material, filters, subtitles and autocrop.
An old codec obsoleted by the preceding ones.
An even older codec.
MPEG-1 is the standard format for VCD, which you can burn on CDR media and playback on a TV with a VCD-compatible DVD player. If you only plan to playback on a computer, use MPEG-4, as it takes less disk space for the same quality at low bitrates. The ffmpeg MPEG-1 encoder has a remarkable image quality, and it's incredibly fast.
The mpeg2enc engine offers a perfectly standard MPEG-1 encoding for VCD use.
MPEG-2 is the standard format for SVCD, CVD (which you can burn on CDR media and playback on a TV with a SVCD-CVD compatible DVD player) and DVD. The mpeg2enc MPEG-2 engine is Altivec optimized, has many options and is a very good engine for CVD and SVCD encoding.
ffmpeg engine "fast mpeg-2" encoding has vastly improved. This new encoder comes with 2-pass support and VBR and is extremely fast. It now supports SVCD and DVD creation.
Choose this setting when you don't want to re-encode the video stream, but just pass it through and copy it into the destination file. Useful when you just want to convert the audio, and leave the video as-is in the source file.
ffmpeg engine "H263 (3GP)" encoding is a video format used on smart phones and compatibles handheld devices. It is optimized for very small bitrates so as the movie keep small to fit in todays limited memories of these devices. Select the "3GP" quick preset to encode with default settings. Depending on the specifications and memory available in your playback device, you should adjust settings to obtain the best image quality, then save a ffmpegX preset file with your optimized settings. If you use Bluetooth, the Apple Bluetooth File Exchange application will allow you to easily send the encoded .3gp file to your device. Note: some phones could need installation of a video player software in order to play 3gp files (see the website of your phone brand to check). Note: video for phones using the "Smartmovie" player can be encoded by simply using the DivX/XviD codecs with appropriate size and bitrates (save a preset file when you found the best settings for your phone).
ffmpeg engine "DV" video is a standard DV codec supporting both PAL and NTSC framerates. The PCM audio mode should be used for audio. Always open the source file first, then select the quick preset without changing the settings: don't change the image size and don't use the bitrate calculator to change bitrate when encoding to DV format, as DV implies standardized settings.
ffmpeg engine "XviD" codec uses the same encoder core as mencoder XviD, though it benefits from overall ffmpeg speed and can be up to 300% faster than mencoder XviD. It can be used when you need speed and don't need the advanced subtitling and filtering capabilities of mencoder.
This is the same codec as ffmpeg AVI MPEG4, though a Quicktime .MOV container is used instead of AVI. The resulting movie can be played back and edited natively in Quicktime Player and other Quicktime applications like Final Cut Pro, even without installing additional DivX codecs. (Note: The MOV format may not be playable on PCs or DivX-hardware players not compatible with Quicktime). Select the "MOV mpeg-4" quick preset to use this codec with default settings and AAC sound. Use it to convert your mpeg/vob files to an editable format with a small file size, so as to edit them, or archive them without needing terabytes of storage. Use it to convert your big .DV captures into very small, and still editable files (enable "Deinterlace" when converting .dv files). Use it if you don't need PC/DivX hardware players compatibility and prefer to keep your movies in a Quicktime MOV container and play them back with Quicktime, taking advantage of all Quicktime superior features and available applications.
Same as preceding one but with XviD codec.
This is the same codec as ffmpeg AVI MPEG4, though a MPEG-4 .MP4 container is used. Use it with AAC sound.
This is the same codec as ffmpeg AVI XviD, though a MPEG-4 .MP4 container is used. Use it with AAC sound.
This is the same codec as ffmpeg mpeg-2, though a mpeg transport stream container (.TS) is used. Use it with MP2 sound (still experimental, may not work on all hardware decoders).
This is the new H.264/Advanced Video Codec, encoded in a MP4 container with AAC audio, with incredible quality and smaller filesizes than mpeg-4.
The same codec as the preceding one, but the x264 encoding engine is used instead of mencoder. Allows access to some additional options like AVC level for compatibility with iPod.
Flash video is used to stream video on a website or a blog. A detailed guide about this format is available here.
Use this control to enable or disable the video encoding. Useful when you just want to convert the audio and don't want the video at all in the output. Currently only works with ffmpeg codecs.
The bitrate calculator box helps to choose a video bitrate value used for the encoding of the video stream. The video bitrate, in kbit/sec, is a size measurement of the flow of data used to encode the video file. Eg a bitrate of 1000 kbit/sec, means using 1000 kbit to store one second of video (that is, about 24 to 30 images, depending on the framerate, so lower framerates will lead to better quality at same bitrate). This doesn't mean the encoder will use exactly and constantly this value, as the actual value will also depend from the encoding engine rate-control system and from encoding settings, eg in VBR mode the actual bitrate will greatly vary depending upon the complexity of the movie. To use the calculator, you should first choose an image size (normally equal or smaller than the source) and the encoding framerate. Then using the "Best" calculator button you will calculate a "best" bitrate suited to the current image size and framerate. The "Rate" calculator button will calculate a bitrate (including the audio part) suited to fit a source of specified duration (in minutes) into one or more CDs of the specified media (or into a given size in MB). Always compare the resulting value to the "Best" value and don't use a bitrate much higher or much lower than the "Best" value. The "Time" calculator button is the opposite as "Rate", ie it calculates the duration of material (including audio) which can be encoded at the current bitrate to fit one or more CDs of the specified media (or into a given size in MB). Clicking "Best" immediately followed by "Time" will tell you the duration of material which can be encoded at best quality bitrate. The "Size" calculator button calculates the encoded file size in MB from specified bitrate and duration. The "Img" calculator button calculates the image size in current aspect ratio suited to current bitrate and framerate (bits per pixels) (don't use an image size larger than source image size, or larger than your video playback device image size). The "Auto" calculator button calculates both a bitrate suited to fill selected CD size, as well as an image size suited to such bitrate for best bpp image quality. The audio bitrate is also taken into account as set in the audio tab. Remember that if the resulting horizontal image size is lower than 480 you will obtain less than SVCD quality, and if it is lower than 240 you will obtain less than VCD quality, so in such cases you should consider to increase the media size (eg use two CDs instead of a single one). You should also never encode to a size greater than the source image size. The "Auto" and "Img" buttons are meant for mpeg-4 based formats only (DivX, XviD) and are not available for mpeg-1/2 based formats (VCD, CVD, SVCD, DVD) as the image size for these must be the standard one.
When using the bitrate calculator, or entering a value in the video bitrate field, ffmpegX will check automatically if the value is in a 'safe' quality range depending on current image size and framerate, and colorize the value accordingly:
red=the bitrate is too low for the selected image size, if you use it you'll be compressing your movie too much and the quality will not be acceptable with the current image size (consider choosing another bitrate, or use a smaller size);
green=this bitrate is quite good, if you choose it you'll obtain good quality for the current image size;
blue=this bitrate is too high, if you choose it you will not improve quality comparing to "green" values and you'll be wasting space on your disks (consider choosing another bitrate, or use a larger image size, though not larger than the source image size)
Check the Guides for more specific directions on how to use the Bitrate calculator. When enabling the ffmpeg option "Use only i-frames" it is normal that the bitrate requirements will greatly increase.
Sets the video size in pixels (width x height). The width and height must be evenly divisible by 16 for most codecs to work properly.
Use this pulldown menu to set a predefined video size values (eg VCD or SVCD), or to calculates the height from the width by applying the specified ratio (eg 2.35:1, 16:9 or 4:3). Using 16:9 ratios or presets also apply a 16:9 special flag to mpeg-2 streams.
Sets the framerate of the converted video. To avoid audio sync problems, don't try to convert PAL into NTSC or the opposite. PAL has only one value, though NTSC has two values (NTSC and NTSC FILM). Almost all NTSC DVDs are encoded at NTSC FILM rate, while TV or camera material is encoded at NTSC rate. mpeg-2 can also have 3:2 pulldown activated so video encoded at NTSC FILM will be played back at NTSC rate.
For mencoder codecs, you can specify VIDEO_TS input parameters in this box: title, start and end chapters (optional), angle (optional).