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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
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commit 3a5f191bbe
1 changed files with 10 additions and 9 deletions
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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) CDRwin's .BIN files) without extracting mpeg files first (with tools like vcdgear)
It accepts all PES variants, including files created by VDR. It accepts all PES variants, including files created by VDR.
Note: VOB (video object) is simple mpeg stream, but it usually has 01BD 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. 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 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. small parts with standard file tools (dd, cut) without destroying it.
Codecs: video is always mpeg video (mpeg1, mpeg2 or mpeg4). 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) 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. FPS: mpeg2 content allows variable framerate, in form of delayed frames.
It's mostly used for playback 24fps contant at 29.97/30 fps (NTSC) rate. It's mostly used for playback 24fps content at 29.97/30 fps (NTSC) rate.
(so called Telecine or 3:2 pulldown effect) (so called Telecine or 3:2 pulldown effect)
It means you see 30 frames per second, but there are only 24 different 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. pictures and some of them are shown longer to fill 30 frame time.
@ -35,7 +35,7 @@
- AVI streams. - AVI streams.
Two kind of RIFF AVI files exists: 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). 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 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 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 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 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. played as non-interleaved otherwise you get a-v desync or buffer overflow.
MPlayer supports 2 kind of timing for AVI files: MPlayer supports 2 kind of timing for AVI files:
- bps-based: it is baed on bitrate/samplerate of video/audio steram. - bps-based: it is baed on bitrate/samplerate of video/audio steram.
this method is used by most players, including avifile and wmp. 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 I also note, that most AVI encoders/multiplexers create bad files if
using VBR audio. only 2 exception (known by me): NaNDub and MEncoder. 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 streams:
ASF (active streaming format) comes from Microsoft. they developed two 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, Asf uses fixed packet size, so it is seekable without any INDEX block,
and broken files are playable well. 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. WMV1 and WMV2. but any codecs allowed.
audio is usually wma or voxware, but any codecs allowed. audio is usually wma or voxware, but any codecs allowed.