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1 | 1. prepare your video files for Ben: |
2 | |
3 | Use ffmpeg2theora or ffmpeg with vp8, vorbis, mkv. |
4 | |
5 | When using theora, try to use a video width and height that are a multiple of |
6 | 16. Currently theora decoding displays strange borders, if size is not a |
7 | multiple of 16. |
8 | |
9 | Try to use an audio sampling rate of 44100 for the vorbis audio. If the |
10 | automatic resampling of the alsa OSS emulation is triggered, quality degrades |
11 | a lot. Alternatively use 'mplayer -af resample=44100:1:1' on playback. |
12 | |
13 | For encoding try to use libtheora 1.2 ("ptalarbvorm") which improves visual |
14 | qality a lot compared to previous versions. Always encode with |
15 | constant-quality *not* giving a bitrate target. |
16 | |
17 | Here's an example encoding command: |
18 | |
19 | ffmpeg2theora -o output.ogv input.avi \ |
20 | -v8 -x320 -y176 \ |
21 | -a0 --channels 2 --samplerate 44100 |
22 | |
23 | Yielding a pretty high visual quality (-v8 i.e. "80%"). Use -v6 for |
24 | approximately half the bitrate with moderate quality. |
25 | |
26 | 2. play your files with Ben: |
27 | |
28 | mplayer output.ogv |
29 | |
30 | In case sample rate doesn't match 48000 the default will be to perform quick |
31 | resampling, introducing noticeable quality degradation. Add -af |
32 | resample=44100:0:1 to improve audio quality at the cost of a few percent of |
33 | CPU usage. |
34 | |
35 | (Assumptions: |
36 | |
37 | the following options should be set in your ~/.mplayer/config: |
38 | |
39 | volume=10 |
40 | vo=cvidix |
41 | screenw=320 |
42 | screenh=240 |
43 | fs=1 |
44 | ac=tremor |
45 | quiet=1 |
46 | ) |
47 |