Okay here is the first draft of a user manual for afropic, i'll outline it better later and also post it on the website and distribute it with all versions of afropic from now on... hope this sheds some light on any mysteries about it.


---


AfroPic 0.3 Explained

Tab 1: Decoding/BC

DECODING:

Auto Size:
This feature functions to select an auto size for a variety of formats, if none of them fit your needs select custom and put in your desired width and height.

Frame rate:
Choose from one of three frame rates
23.976 – NTSC Film
25 – PAL
29.97 – NTSC Video

Aspect Ratio:
1:1 – VGA
4:3 – Letterbox (it’s best most of the times to stick with this aspect ratio, even if the input is 16:9, the only time to choose otherwise is DVD down sampling, or if your not authoring to VCD or SVCD)
16:9 – Widescreen/Anamorphic

Fast Mode Denoise/Deinterlace:
If you choose deinterlace it will use yuvdenoiser to deinterlace the material. Unfortunately while yuvdenoise does an excellent deinterlacing job, it is dreadfully slow so if you would like to speed up the deinterlacing process additionally choose Fast Mode Denoise. Fast mode denoise by itself will do a fast, mild denoise.

Change Interlacing:
Use this ONLY if you know the interlacing mode of the input source stream. Be certain if you change the interlacing mode here to change it in the Encoder tab as well.


BITRATE CALCULATOR

Input the hours and minutes for the file that you are re-encoding. Additionally select the number of CD’s (or DVD’s) you wish the material to fit on. After you select calculate it will input the newly calculated bit rate into the bit rate text field in the encoding tab. But it will NOT change the mode in the Encoding tab, so if you leave it at the default of SVCD it will still encode at 2500, (hence why the box is still disabled) you need to change to USER SVCD, USER VCD, DVD, MPEG-1 or MPEG-2 to be able to control the bit rate.

Tab 2: Encoding

Mode/ Bit rate:
Choose from MPEG-1, USER VCD, VCD, USER SVCD, SVCD, and DVD.
If you choose SVCD or VCD you will be constrained to the bit rate of 2500 (SVCD) or 1152 (VCD) if you don’t want to use those standard bit rates you need to select USER SVCD or USER VCD.

VBR/Quantization reduction:
VBR: Minimum quantization of the output stream. Quantization controls the precision with which image information is encoded. The lower the number the higher the quality but the greater the required data rate. For VCD resolution anything below 8 or so produces pretty good quality video. For SVCD the equivalent level is around 10. If this option is set a variable bit rate stream is produced. This is more efficient overall but variable bit rate MPEG1 cannot be played by many hardware decoders and/or DVD/(S)VCD drives. If you intend to use a software decoder you'd be insane not to use variable bit rate.

Quantization reduction: This flag sets the amount quantization is reduced for blocks containing unusually large amounts of sharp image detail. Setting this value 0.0 produces the most efficient use of bits but may cause visible/artifacting around detailed sections. A larger value may help suppress artifacts; however, on noisy source material this may cause a "swimming" effect on textured backgrounds as the noise cause blocks to be boosted at random

Motion Search Radius:
This flag sets the motion estimation search radius. For most purposes the default (16) should be just fine. For high resolution MPEG2 and active scenes it may be worth bumping it up. However, this will make encoding significantly slower. There is little point reducing the radius. Speed gains are not huge and the impact on quality can be marked.


NOTE: It is NOT wise to use VBR with VCD, from my understanding it creates a very jittery output video

Enable 3:2 Pulldown: Setting p only makes sense for 24frame/sec Movie source material. It sets flags in the output stream that tell the decoder to play the movie as NTSC 60field/sec video using "3:2 pulldown". This is vastly more efficient than encoding as 60field/sec video. The classic application is to transcode a PAL encoded movie (24fps played too fast at 25 fps!) into NTSC (see the f flag).


Max/Min GOP Size:
These flags set the minimum and maximum groupofpicture (GOP) size for the output MPEG stream. By default both are set to 12 to suit VCD encoding. If the two values are not identical mpeg2enc applies a simple scene change detection procedure to try to select GOP sizes that ensure big changes of image coincide with the fully encoded I frame starting a new GOP. This can help prevent transient "blockiness". For VCD/SVCD/DVD the largest GOP size is 15 for PAL or 18 for NTSC. Reasonable minimum GOP sizes are 6 or 9. A larger GOP size can help reduce the bit rate required for a given quality. However, this really only applies to high quality source material with little noise (e.g. digital video). For broadcast material there is little point setting GOP size much
beyond 21 or 24. Even with good source material diminishing returns set in quite rapidly.
Note: Mpeg2enc is currently hardwired to produce 2 B frames between each I/P frame
unless the GOP size forces less. This is reasonable for medium to high bit rates (>= 1Mbps) but probably suboptimal for low bitrate encoding.

4x4/2x2 Reduction Factor:
These options control how radical the encoder is in throwing away apparently poor candidate estimates during motion estimation. A setting of 1 means very few blocks are discarded early which makes for slow encoding but quality as good as it gets. A setting of 4 makes for fast encoding but can impact quality. The 4 flag controls discarding during the initial 4*4 subsampled search stage, the 2 flag controls discarding during the secondary 2*2 subsampled stage.

High Quality Filter:
Reduce:
Setting this flag adjusts the way texture detail is quantised to reduce the precision with which of high- frequency information encoded. This is very useful for mildy noisy sources.
Maintain:
Setting this flag makes the encoder encode as much high- frequency information as possible. This is a good setting for maximising quality at VCD resolution with good quality lownoise source material. It can also help with "swimmy" material if you can spare the bitrate!

Header at every gop:
if you select this you will be able to enabled chapters in dvd studio pro if you use the material in there afterwards.

Tab 3: Audio/Mplex


Encode audio:
If this button is deselected no audio will be encoded.

Audio Bitrate:
Choose from 160, 192 or 224, the higher the bitrate the higher the audio quality.

Sampling Rate:
Choose from 44100 or 48000. 44100 is necessary for SVCD/VCD encoding, 48000 is necessary for DVD encoding.

Input Format:
Currently you can input AC3/mp2/mov. If you select mp2 you can NOT re-sample the audio, it will just rip the mp2 out of the original file and multiplex it with the newly encoded video. If you select mov AfroPic will be expecting a quicktime movie file. Unfortunately not all quicktime audio will work (I’m not certain why, but this will be changed when I process audio encoding separate of Mediapipe, currently I’m limited by what the QuickTime audio decoder pipe will properly decode)


Multiplex:
If this button is deselecting AfroPic will only output the video and audio files.

Force Segment:
Only use this segmenting feature if you do NOT plan on post-processing to .bin/.cue files. (to safeguard from this once split is chosen in the post-processing box force segment in multiplex is disabled) However if you don’t want to post process then select the file size you would like the video chunks to comply to.

Tab 4: Pre/Post Processing:

Input VOB Size:
Less than 4 GB: Choose this when your input VOB/MPG file is less than 4 GB, by default this is selected.
More than 4 GB: Choose this when your input VOB/MPG is more than 4 GB.

NOTE: This setting does NOT apply for quicktime video input!

Demux then Remux:
Choose this setting if there is a timecode problem with the VOB you are selecting (UNLESS it is over 4 GB, because in that case by default it demuxes and remuxes) you can test to see if there is a timecode problem by opening the VOB in quicktime and seeing if the time is displayed properly, (i.e. in the case of an improper timecode quicktime may report a 2 hour movie to be only 2 minutes or something, in that case or any similar case choose demux then remux)

Save Shell To Desktop:
To run more efficiently AfroPic creates a shell script which it outputs to the terminal instead of sending a huge chunk of text to the terminal. If you would like to have this shell script copied to the desktop before it starts encoding you can select this option (helpful for troubleshooting)

Post Process:
Select this if you would like the files converted to bin/cue or DVD folders.

Split:
Select this if you would like to split the bin/cue files into more than one cd (generally I would assume you do) Make sure the CD number you choose here corresponds with the CD number you choose in the bitrate calculator. If you choose DVD folder as the output the split number is ignored.

Output Format:
Bin/cue – Choose this if you would like to output the file as bin/cue after multiplexing.
DVD Folders: When this option is selected after multiplexing it will format your files into a DVD folder that can be dropped and burned in toast.



IMPORTANT NOTE: If you are encoding to bin/cue (specifically SVCD) that you are planning to burn in cdrdao (MissingMediaBurner, cdrdaox) be certain to open the cue file in TextEdit BEFORE inputting to cdrdao. Remove each occurrence of “FLAGS DCP” in the cue file or cdrdao will error out before burning.

IMPORTANT NOTE 2: As of the time of writing this document DVD Folders is still a work in progress, technically it DOES work with ac3 audio, but right now make certain to choose mp2 and 48000 khz, the default audio it looks for is mp2, and I haven’t figured out how to feed in a different audio format yet, hopefully that will be implemented in a later version.