Transcoding

Topics: NTSC, Film and video technology, Telecine Pages: 8 (2836 words) Published: August 26, 2013
X264 Transcoder
The x264 transcoder encodes one video stream into one or more video streams in H.264 format, using the x264 codec. This transcoder is GPU accelerated using Lightspeed technology. Delete. To delete this transcoder, click the X icon immediately right of the Source button. Input streams are displayed on the left (noted by a down arrow) side of the transcoder; output streams (as indicated by an up arrow) are displayed on the right. Note: When collapsed, transcoder components provide a summary of configuration details in the title bar of the component. Transcoder Toolbar Icons

Gear > Duplicate. Click to duplicate the selected transcoder. This saves you the effort of configuring a new transcoder when all you want to do it change a few parameters. Or, right-click and select Duplicate. Up/Down Arrow. Click to move the selected input up and down the list, for organization/readability purposes. Alternatively, use drag-and-drop: select a component and drag it to its new location in the list. Details Arrow. Click to show/hide all of the inputs in this action. Plus Sign. Click to another transcoder to this action.

Input Stream
Select the video stream that you wish to use as the input to this transcoder: Stream Checkbox. Check to activate or deactivate this stream for encoding. Stream Name. Select the name of the input stream to transcode. Transcoder Details

Select the X264 Transcoder to enable and configure the codec settings. Analysis
Click the details icon to specify analysis settings.
Look Ahead (--rc -lookahead). Specify the number of frames that the encoder uses to predict more difficult areas to encode, and save bits for those sections. This setting is used for rate control, and effectively sets the VBV window. Range: 10 to 250. IP Ratio (--ipratio). Specify the target average increase in the quantizer for I-frames compared to P-frames. Higher values increase the quality of I-frames generated. Range: 1 to 10. Frame Type

Click the details icon to specify frame type settings.
Key Frame Interval (--keyint). Specify the maximum distance between keyframes. Range: 10 to 1000. Scene Detection Threshold (--scenecut). Check to enable scene detection and specify the threshold for I-frame detection. x264 calculates a metric for every frame to determine how different it is from the previous frame. If the metric is lower than this value, a scene cut is detected. Range: 1 to 100. Maximum B-frames (--bframes). Specify the maximum number of consecutive B-frames between P-frames. Range: 1 to 8. B-frame Placement Algorithm (--b -pyramid). Select adaptive B-frame placement decision algorithm from the dropdown menu. This setting controls how x264 decides between placing a P- or B-frame. Disabled - Always pick B-frames.

Fast - Faster, speed slightly increases with higher maximum b-frames setting. Optimal - Slower, speed significantly decreases with higher maximum b-frames setting. B-Frame Reference Pyramid. Allow the use of B-frames as references for other frames. Without this setting, frames can only reference I- or P-frames. Although I/P-frames are more valued as references because of their higher quality, B-frames can also be useful. B-frames designated as references will get a quantizer halfway between P-frames and normal B-frames. You need to use at least two B-frames before B-pyramid will work. If you're encoding for Blu-ray, use None or Strict.

None - Do not allow B-frames to be used as references.
Strict - Allow one B-frame per mini-GOP to be used as reference; enforces restrictions imposed by the Blu-ray standard. Normal - allow numerous B-frames per mini-GOP to be used as references. Reference Frames (--ref). maximum number of frames that a frame can reference. More reference frames provides better quality, because the encoder has more frames in which to find similarities, but increases CPU utilization. Range: 0 to 16. Resolution

Click the details icon to specify frame settings.
Width. Select the...
Continue Reading

Please join StudyMode to read the full document

You May Also Find These Documents Helpful

  • Transcoding Jpeg Essay

Become a StudyMode Member

Sign Up - It's Free