mirror of https://bitbucket.org/ausocean/av.git
61 lines
2.0 KiB
Go
61 lines
2.0 KiB
Go
/*
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DESCRIPTION
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decode.go provides slice decoding functionality.
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AUTHORS
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Saxon A. Nelson-Milton <saxon@ausocean.org>
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LICENSE
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Copyright (C) 2019 the Australian Ocean Lab (AusOcean).
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It is free software: you can redistribute it and/or modify them
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under the terms of the GNU General Public License as published by the
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Free Software Foundation, either version 3 of the License, or (at your
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option) any later version.
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It is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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You should have received a copy of the GNU General Public License
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in gpl.txt. If not, see http://www.gnu.org/licenses.
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*/
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package h264dec
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// picOrderCntType0 is used to return topFieldOrderCnt and bottomFieldOrderCnt
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// when pic_order_cnt_type i.e vid.PicOrderCntType == 0, using the process
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// defined in section 8.2.1.1 of the specifications.
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func picOrderCntType0(vid VideoStream, ctx SliceContext) (topFieldOrderCnt, bottomFieldOrderCnt int) {
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prevPicOrderCntMsb, prevPicOrderCntLsb := 0, 0
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topFieldOrderCnt, bottomFieldOrderCnt = -1, -1
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// NB: We're currently only handling IDRs so panic.
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if !vid.currPic.isIDR {
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panic("not implemented")
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}
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switch {
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case (ctx.PicOrderCntLsb < prevPicOrderCntLsb) && ((prevPicOrderCntLsb - ctx.PicOrderCntLsb) >= (vid.maxPicOrderCntLsb / 2)):
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vid.picOrderCntMsb = prevPicOrderCntMsb + vid.maxPicOrderCntLsb
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case (ctx.PicOrderCntLsb > prevPicOrderCntLsb) && ((ctx.PicOrderCntLsb - prevPicOrderCntLsb) > (vid.maxPicOrderCntLsb / 2)):
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vid.picOrderCntMsb = prevPicOrderCntMsb - vid.maxPicOrderCntLsb
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default:
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vid.picOrderCntMsb = prevPicOrderCntMsb
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}
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if !vid.currPic.isBottomField {
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topFieldOrderCnt = vid.picOrderCntMsb + ctx.PicOrderCntLsb
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}
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if !vid.currPic.isTopField {
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if !ctx.FieldPic {
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bottomFieldOrderCnt = topFieldOrderCnt + ctx.DeltaPicOrderCntBottom
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} else {
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bottomFieldOrderCnt = vid.picOrderCntMsb + ctx.PicOrderCntLsb
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}
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}
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return
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}
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