mirror of https://github.com/mpv-player/mpv
56 lines
2.1 KiB
Plaintext
56 lines
2.1 KiB
Plaintext
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In the RV30 format, another encapsulated data layer for the video stream
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has been introduced. In lack of a name I'll call them sub packets, the
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normal packets which exist in RV10 I'll call - well - packets. The stream
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of bytes which is put in one memory block is named block.
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The format extension has been * by wild guessing and comparing the
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received data between the original viewer and the demuxer.
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Every packet may contain one or more sub packets, and one block may
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be contained inside one or more adjacent (sub) packets.
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A sub packet starts with a small header (two letters are one byte):
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aa(bb)[ccccdddd{eeee}ff]
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aa: indicates the type of header
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the 2MSB indicate the header type (mask C0)
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C0: the [] part exists, but not ()
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00, 80: the data block is encapsulated inside multiple packets.
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bb contains the sequence number, beginning with 1.
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80 indicates the last sub packet containing data for the
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current block. no C0 or 40 sub packet follows until
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the block has been finished with a 80 sub packet.
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No packet with another stream than the current video stream
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is inside the sub packet chain, at least I haven't seen
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such case - the demuxer will shout in this case.
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40: [] does not exist, the meaning of bb is unknown to me
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data follows to the end of the packet
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mask 3F: unknown
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bb: unknown
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cccc: mask 3FFF: length of data
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mask C000: unknown, seems to be always 4000
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dddd: when it's 0, {} exists (only in this case)
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mask 3FFF: I thought it would have been the offset inside the
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block, is not correct in every case. Just appending the
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data works better, ignoring it.
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mask C000: like cccc, except the first case
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eeee: only exists when dddd exists and is zero. contains the data
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dddd should contain in the second case. don't know what the developers
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had in mind.
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ff: sequence number for the data blocks, beginning with 0
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packet header:
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ushort unknown
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ulong blocksize
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ushort streamid
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uchar reserved
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uchar flags 1=reliable, 2=keyframe
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