Update of /cvsroot/mplayer/main/DOCS/tech In directory mplayer:/var/tmp.root/cvs-serv3494 Modified Files: formats.txt Log Message: typos fixed Index: formats.txt =================================================================== RCS file: /cvsroot/mplayer/main/DOCS/tech/formats.txt,v retrieving revision 1.1 retrieving revision 1.2 diff -u -r1.1 -r1.2 --- formats.txt 7 Nov 2001 23:01:49 -0000 1.1 +++ formats.txt 7 Nov 2001 23:15:19 -0000 1.2 @@ -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.