Make it more structured.
Anton Khirnov authored on 2014/04/12 22:20:01... | ... |
@@ -347,29 +347,37 @@ avconv -re @var{<normal input/transcoding options>} -movflags isml+frag_keyframe |
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@section mp3 |
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-The MP3 muxer writes a raw MP3 stream with an ID3v2 header at the beginning and |
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-optionally an ID3v1 tag at the end. ID3v2.3 and ID3v2.4 are supported, the |
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-@code{id3v2_version} option controls which one is used. Setting |
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-@code{id3v2_version} to 0 will disable the ID3v2 header completely. The legacy |
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-ID3v1 tag is not written by default, but may be enabled with the |
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-@code{write_id3v1} option. |
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- |
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-The muxer may also write a Xing frame at the beginning, which contains the |
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-number of frames in the file. It is useful for computing duration of VBR files. |
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-The Xing frame is written if the output stream is seekable and if the |
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-@code{write_xing} option is set to 1 (the default). |
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- |
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-The muxer supports writing ID3v2 attached pictures (APIC frames). The pictures |
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-are supplied to the muxer in form of a video stream with a single packet. There |
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-can be any number of those streams, each will correspond to a single APIC frame. |
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-The stream metadata tags @var{title} and @var{comment} map to APIC |
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-@var{description} and @var{picture type} respectively. See |
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+The MP3 muxer writes a raw MP3 stream with the following optional features: |
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+@itemize @bullet |
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+@item |
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+An ID3v2 metadata header at the beginning (enabled by default). Versions 2.3 and |
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+2.4 are supported, the @code{id3v2_version} private option controls which one is |
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+used (3 or 4). Setting @code{id3v2_version} to 0 disables the ID3v2 header |
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+completely. |
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+ |
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+The muxer supports writing attached pictures (APIC frames) to the ID3v2 header. |
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+The pictures are supplied to the muxer in form of a video stream with a single |
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+packet. There can be any number of those streams, each will correspond to a |
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+single APIC frame. The stream metadata tags @var{title} and @var{comment} map |
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+to APIC @var{description} and @var{picture type} respectively. See |
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@url{http://id3.org/id3v2.4.0-frames} for allowed picture types. |
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Note that the APIC frames must be written at the beginning, so the muxer will |
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buffer the audio frames until it gets all the pictures. It is therefore advised |
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to provide the pictures as soon as possible to avoid excessive buffering. |
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+@item |
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+A Xing/LAME frame right after the ID3v2 header (if present). It is enabled by |
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+default, but will be written only if the output is seekable. The |
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+@code{write_xing} private option can be used to disable it. The frame contains |
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+various information that may be useful to the decoder, like the audio duration. |
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+ |
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+@item |
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+A legacy ID3v1 tag at the end of the file (disabled by default). It may be |
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+enabled with the @code{write_id3v1} private option, but as its capabilities are |
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+very limited, its usage is not recommended. |
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+@end itemize |
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+ |
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Examples: |
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Write an mp3 with an ID3v2.3 header and an ID3v1 footer: |