Method 2: Full Guide
So you have chosen the more advanced method. Let's go.
Start Videora iPhone Converter and click on the "Settings" button at the top.
Under "Encoding Profiles", listed are several profiles that you can select for encoding - each profile has a pre-defined set of settings (eg. resolution, bit-rate, and encoding options). The iPhone supports both H.264 video and MPEG-4 (Simple Profile) video - H.264 is the new codec which is more efficient than MPEG-4 SP, and you should use H.264 whenever you can. In addition to editing an existing profile, you can also create your own.
To create your own profile (which is optional, so if you don't mind using an existing profile, skip to the next page), click on the "New Profile" button.
In the "General" section, you can specify a title for your profile, and select an encoder. For best quality, select "iPhone - 2-Pass - FFmpeg MINB", this will activate 2-pass encoding which doubles the encoding time, but also improves quality. You can also set a default starting position and encoding duration, if you don't wish to encode the entire video.
Now go to the "Video" section. Here is where you can configure the video settings for this profile. Let's go through the options:
- Video Codec: Select H.264 for MPEG-4 SP as your video codec.
- Profile: For iPhone video, only one profile is available for each codec (Simple Profile for MPEG-4 and Baseline Profile for H.264).
- Level: The "Level" determines the maximum resolution that is supported (and taking into account the supported resolutions of the device/encoder). Level 2.1 and 3 are available to select for H.264, 2.1 limits the resolution to 480x320, while Level 3 limits the resolution to 640x480
- Bitrate Mode: You can use ABR (Average BitRate) mode or "Automated 2-Pass"
- Bitrate (kbps): You can select a bitrate to use for your video - the higher the bitrate, the larger the file size (you can use a bitrate calculator to work out the file size, or do it manually - 1 MB/s => 1024 KB/s => 8192 kbps). The bitrate is also dependent on the video resolution - 768 kbps should give you acceptable (at least when viewed on the iPhone) quality video for H.264 @ 480x320.
- Resolution: You should keep all the settings at "Original", unless you want to resize the video.
- AutoResize: Keep this enabled, this will automatically resize your video. You can set a maximum resolution (based on your "Level" selection earlier).
- AutoFramerate: Keep this enabled
Click on the "General 2" tab. More options are available:
- Crop: You can use these settings to crop the video (eg. use it to remove black borders around the video)
- Padding: The reverse of cropping, add a border around the video
- AviSynth: Enables AviSynth processing. Leave it disabled unless you know what you are doing.
- Additional CLI Parameters: You can add additional CLI commands for ffmpeg here ... if you don't know what this means, leave it blank.
Click on the "Advanced 1" tab. More options are available:
- Rate Control - Buffer Size: Specify the playback buffer size - too large and the video takes longer to load, to low and the video might stutter.
- Rate Control - Minimum Bitrate: Usually keep this at 0
- Rate Control - Maximum Bitrate: Specifies the maximum bitrate allowed in the video buffer
- Keyframe Interval: Usually set this to 10 times the framerate of the video (keyframe every 10 seconds)
- Number of Threads: Number of CPU threads to use for encoding
Click on the "Advanced 3" tab. Only one option here, and that is to enable CABAC. Enabling it will improve quality, at the expense of encoding speed and decoding speed.
Click on the "Audio" button at the top, here you can configure the audio options:
- Codec: Only one option here, and that's AAC-LC (low complexity)
- Mode: Again, only one option, ABR
- Bitrate (kbps): You can select the bitrate. AAC-LC is more efficient than MP3, so 128 kbps should equate to a 160 kbps MP3 to give you great quality
- Channels: Stereo, Mono or Original
- Sample Rate (Hz): Keep this at original
- Volume: Increase/decrease the audio volume if you wish
Press "OK" to save your profile.