why is my encoding speed slow dvdfab mac

2-pass encoding is the most common multi-pass encoding. Multi-pass encoding is used only for VBR encoding, because CBR encoding doesn't offer any flexibility to change the bitrate. Multi-pass encoding takes much longer than single-pass encoding, because every pass means one pass through the input data (usually through the whole input file). Multi-pass encoding cannot be used in real-time encoding, live broadcast or live streaming.

Multi-pass encoding is used when the encoding quality is most important. Single-pass VBR encoding is usually controlled by the fixed quality setting or by the bitrate range (minimum and maximum allowed bitrate) or by the average bitrate setting. Single-pass encoding is used when the encoding speed is most important - e.g.

Single-pass encoding analyzes and encodes the data 'on the fly' and it is also used in constant bitrate encoding. Difference between 1 - pass & 2 - pass encoding

But by using VBR and multi-pass, encoder “knows” that this piece is OK with lower bitrate and that bitrate can be then used for more complex scenes, thus creating better quality for those scenes that require more bitrate. The best way to understand why this is used is to think of a movie - when there are shots that are totally, absolutely black, like scene changes, normal 1-pass CBR encoding uses the exact same amount of data to that part as it uses for complex action scene.

In video encoding, two-pass encoding is usually controlled by the average bitrate setting or by the bitrate range setting (minimal and maximal allowed bitrate) or by the target video file size setting. In the second pass, the collected data from the first pass is used to achieve the best encoding quality. In the first pass of two-pass encoding, the input data from the source clip is analyzed and stored in a log file.

Why is my encoding speed slow dvdfab mac