Encoder Options for mp4 Files
This file format can be used on iPod, iPhone, PSP, PS3 and other devices.
MP4 files are saved using H.264, MPEG4 or H.265 compression.
The image reproduction quality level. Best gives an output video with the maximum quality of reproduction resulting in the biggest file size. Least gives minimum quality of reproduction with the smallest file size. This is only available for the internal encoder.
Average Bit Rate
Enable this option to indicate the long-term desired average data rate (in kilobits per second). A higher value results in better image quality but bigger file size. Note that this is not a hard limit: the resulting data rate could be lower or higher depending on the video size and actual contents. If this option is disabled then the encoder does not set a limit, and the Quality setting, if enabled, should determine the file size.
- Video Bitrate
Here you specify the bitrate the video is encoded at. The higher the value, the better the quality of the picture and the less artifacts (macro blocks and blurring). You should experiment with this. Please note higher values result in a larger file size.
- Average bitrate
The mean bit rate, and is the main value that affects quality. Maximum bitrate should generally exceed this, but no set margin is required; the Average and Maximum bitrate can safely be the same.
- Maximum bitrate
the absolute maximum bitrate. It does not majorly affect quality but some formats have set values that must not be exceeded (e.g., 10 megabits for DVD video). Sometimes if your maximum bitrate is too low then you will get macro block effects, in which case you should increase BOTH values.
H.265 compressor (only supported in Windows 7 and later versions)
H.265 is a new video compression standard. In comparision to H.264, H.265 offers about double the data compression ratio at the same level of video quality, or substantially improved video quality at the same bit rate.
- Quality (Ratefactor)
Please note that lower values result in a larger file size. You should experiment with this to pick the optimal quality for your needs.
Here you specify the quality rate which will be used by the H.265 video compressor.
The lower the value, the better the quality of the picture and the less artifacts (macro blocks and blurring).
- Encoding Speed
There is a trade off of compression efficiency versus encoding speed. The slower the speed you select, the higher the compression efficiency you get (so that file size is smaller while the quality remains the same).
You should experiment with this to find the optimal speed for your needs.
MP4 files are saved using AAC compression for sound.
You can specify a maximum variable bitrate the sound will be encoded at (the bitrate will not be constant). The higher the value the better the quality of sound.