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typos fixed 

git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@2766 b3059339-0415-0410-9bf9-f77b7e298cf2
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arpi 2001-11-07 23:15:19 +00:00
parent 4d3a277c03
commit 3a5f191bbe
1 changed files with 10 additions and 9 deletions
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19
DOCS/tech/formats.txt
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@ -13,20 +13,20 @@
CDRwin's .BIN files) without extracting mpeg files first (with tools like vcdgear)
It accepts all PES variants, including files created by VDR.
Note: VOB (video object) is simple mpeg stream, but it usually has 01BD
streams which may contain subtitles and non-mpeg audio. Usually found on DVD discs.
packets which may contain subtitles and non-mpeg audio. Usually found on DVD discs.
Headers: mpeg streams has no global header. each frame sequecne (also called GOP,
Headers: mpeg streams has no global header. each frame sequence (also called GOP,
group of pictures) contains an sequence header, it describes that block.
In normal mpeg 1/2 content there are GOPs of 12-15 frames (24/30 fps).
In normal mpeg 1/2 content there are groups of 12-15 frames (24/30 fps).
It means you can freely seek in mpeg streams, and even can cut it to
small parts with standard file tools (dd, cut) without destroying it.
Codecs: video is always mpeg video (mpeg1, mpeg2 or mpeg4).
audio is usually mpeg audio (any layer allowed, but it's layer 2 in most files)
but 01BD streams may contain AC3 or LPCM too.
but 01BD packets may contain AC3, DTS or LPCM too.
FPS: mpeg2 content allow variable framerate, in form of delayed frames.
It's mostly used for playback 24fps contant at 29.97/30 fps (NTSC) rate.
FPS: mpeg2 content allows variable framerate, in form of delayed frames.
It's mostly used for playback 24fps content at 29.97/30 fps (NTSC) rate.
(so called Telecine or 3:2 pulldown effect)
It means you see 30 frames per second, but there are only 24 different
pictures and some of them are shown longer to fill 30 frame time.
@ -35,7 +35,7 @@
- AVI streams.
Two kind of RIFF AVI files exists:
1. interleaved: audio and video contant is interlaved. it's faster and
1. interleaved: audio and video content is interlaved. it's faster and
requires only 1 reading thread, so it's recommended (and mostly used).
2. non-interleaved: audio and video aren't interleaved, i mean first come
whole video followed by whole audio. it requires 2 reading process or
@ -44,6 +44,7 @@
enables -ni option if it finds non-interleaved content. but sometimes
the stream seems to be interleaved, but with bad sync so it should be
played as non-interleaved otherwise you get a-v desync or buffer overflow.
MPlayer supports 2 kind of timing for AVI files:
- bps-based: it is baed on bitrate/samplerate of video/audio steram.
this method is used by most players, including avifile and wmp.
@ -72,7 +73,7 @@
I also note, that most AVI encoders/multiplexers create bad files if
using VBR audio. only 2 exception (known by me): NaNDub and MEncoder.
FPS: must be constant, but skipping frames are allowed.
FPS: only constant framerate allowed, but it's possib;e to skip frames.
- ASF streams:
ASF (active streaming format) comes from Microsoft. they developed two
@ -87,7 +88,7 @@
Asf uses fixed packet size, so it is seekable without any INDEX block,
and broken files are playable well.
Codecs: video is mostly microsoft's mpeg4 variants, MP42, MP43 (aka DivX),
Codecs: video is mostly microsoft's mpeg4 variants: MP42, MP43 (aka DivX),
WMV1 and WMV2. but any codecs allowed.
audio is usually wma or voxware, but any codecs allowed.