mirror of https://bitbucket.org/ausocean/av.git
314 lines
8.1 KiB
Go
314 lines
8.1 KiB
Go
/*
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DESCRIPTION
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jpeg.go contains constants, structure and functions specific to the JPEG.
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AUTHOR
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Saxon Nelson-Milton <saxon@ausocean.org>
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LICENSE
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Copyright (C) 2017 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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along with revid in gpl.txt. If not, see http://www.gnu.org/licenses.
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*/
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package mjpeg
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import (
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"encoding/binary"
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"fmt"
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"io"
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)
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// JPEG marker codes.
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const (
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codeSOI = 0xd8 // Start of image.
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codeDRI = 0xdd // Define restart interval.
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codeDQT = 0xdb // Define quantization tables.
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codeDHT = 0xde // Define hierarchical progression.
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codeSOS = 0xda // Start of scan.
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codeAPP0 = 0xe0 // TODO: find out what this is.
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codeSOF0 = 0xc0 // Baseline
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codeEOI = 0xd9 // End of image.
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)
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var (
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bitsDCLum = []byte{0, 0, 1, 5, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0}
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bitsDCChr = []byte{0, 0, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0}
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bitsACLum = []byte{0, 0, 2, 1, 3, 3, 2, 4, 3, 5, 5, 4, 4, 0, 0, 1, 0x7d}
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bitsACChr = []byte{0, 0, 2, 1, 2, 4, 4, 3, 4, 7, 5, 4, 4, 0, 1, 2, 0x77}
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valDC = []byte{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11}
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valACLum = []byte{
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0x01, 0x02, 0x03, 0x00, 0x04, 0x11, 0x05, 0x12,
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0x21, 0x31, 0x41, 0x06, 0x13, 0x51, 0x61, 0x07,
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0x22, 0x71, 0x14, 0x32, 0x81, 0x91, 0xa1, 0x08,
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0x23, 0x42, 0xb1, 0xc1, 0x15, 0x52, 0xd1, 0xf0,
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0x24, 0x33, 0x62, 0x72, 0x82, 0x09, 0x0a, 0x16,
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0x17, 0x18, 0x19, 0x1a, 0x25, 0x26, 0x27, 0x28,
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0x29, 0x2a, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39,
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0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49,
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0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59,
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0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69,
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0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79,
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0x7a, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89,
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0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98,
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0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7,
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0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6,
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0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3, 0xc4, 0xc5,
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0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3, 0xd4,
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0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe1, 0xe2,
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0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea,
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0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,
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0xf9, 0xfa,
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}
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valACChr = []byte{
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0x00, 0x01, 0x02, 0x03, 0x11, 0x04, 0x05, 0x21,
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0x31, 0x06, 0x12, 0x41, 0x51, 0x07, 0x61, 0x71,
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0x13, 0x22, 0x32, 0x81, 0x08, 0x14, 0x42, 0x91,
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0xa1, 0xb1, 0xc1, 0x09, 0x23, 0x33, 0x52, 0xf0,
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0x15, 0x62, 0x72, 0xd1, 0x0a, 0x16, 0x24, 0x34,
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0xe1, 0x25, 0xf1, 0x17, 0x18, 0x19, 0x1a, 0x26,
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0x27, 0x28, 0x29, 0x2a, 0x35, 0x36, 0x37, 0x38,
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0x39, 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48,
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0x49, 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,
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0x59, 0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68,
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0x69, 0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78,
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0x79, 0x7a, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
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0x88, 0x89, 0x8a, 0x92, 0x93, 0x94, 0x95, 0x96,
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0x97, 0x98, 0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5,
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0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4,
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0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3,
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0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2,
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0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda,
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0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9,
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0xea, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,
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0xf9, 0xfa,
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}
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)
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type multiError []error
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func (me multiError) Error() string {
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return fmt.Sprintf("%v", []error(me))
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}
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func (me multiError) add(e error) {
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me = append(me, e)
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}
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type putter struct {
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idx int
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}
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func (p *putter) put16(b []byte, v uint16) {
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binary.BigEndian.PutUint16(b[p.idx:], v)
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p.idx += 2
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}
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func (p *putter) put8(b []byte, v uint8) {
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b[p.idx] = byte(v)
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p.idx++
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}
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func (p *putter) putBuf(dst, src []byte, l int) {
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copy(dst[p.idx:], src)
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p.idx++
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}
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// writeHeader writes a JPEG header to the writer w.
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func writeHeader(w io.Writer, _type, width, height, nbqTab, dri int, qtable []byte) error {
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width <<= 3
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height <<= 3
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// Indicate start of image.
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err := writeMarker(w, codeSOI)
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if err != nil {
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return fmt.Errorf("could not write SOI marker: %w", err)
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}
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err = writeMarker(w, codeAPP0)
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if err != nil {
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return fmt.Errorf("could not write APP0 marker: %w", err)
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}
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// Write JFIF header.
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b := make([]byte, 16)
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p := putter{}
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p.put16(b, 16)
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p.putBuf(b, []byte("JFIF"), 5)
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p.put16(b, 0x0201)
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p.put8(b, 0)
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p.put16(b, 1)
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p.put16(b, 1)
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p.put8(b, 0)
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p.put8(b, 0)
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_, err = w.Write(b)
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if err != nil {
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return fmt.Errorf("could not write JFIF header: %w", err)
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}
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// If we want to define restart interval.
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if dri != 0 {
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err = writeMarker(w, codeDRI)
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if err != nil {
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return fmt.Errorf("could not write DRI marker code: %w", err)
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}
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_, err := w.Write([]byte{0x00, 0x04, byte(dri >> 4), byte(dri)})
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if err != nil {
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return fmt.Errorf("could not write restart interval value: %w", err)
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}
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}
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// Define quantization tables.
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err = writeMarker(w, codeDQT)
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if err != nil {
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return fmt.Errorf("could not write DQI marker code: %w", err)
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}
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// Calculate table size and create slice for table.
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ts := 2 + nbqTab*(1+64)
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_, err = w.Write([]byte{byte(ts >> 4), byte(ts)})
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if err != nil {
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return fmt.Errorf("could not write quantization table size: %w", err)
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}
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for i := 0; i < nbqTab; i++ {
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_, err = w.Write([]byte{byte(i)})
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if err != nil {
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return fmt.Errorf("could not write quantization table entry no.: %w", err)
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}
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_, err = w.Write(qtable[64*i : (64*i)+64])
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if err != nil {
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return fmt.Errorf("could not write quantization table entry: %w", err)
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}
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}
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// Define huffman table.
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err = writeMarker(w, codeDHT)
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if err != nil {
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return fmt.Errorf("could not write DHT marker code: %w", err)
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}
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var me multiError
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me.add(writeHuffman(w, 0, 0, bitsDCLum, valDC))
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me.add(writeHuffman(w, 0, 1, bitsDCChr, valDC))
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me.add(writeHuffman(w, 1, 0, bitsACLum, valACLum))
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me.add(writeHuffman(w, 1, 1, bitsACChr, valACChr))
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if me != nil {
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return fmt.Errorf("error writing huffman tables: %w", err)
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}
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return nil
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// Start of frame.
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err = writeMarker(w, codeSOF0)
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if err != nil {
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return fmt.Errorf("could not write SOF0 marker code: %w", err)
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}
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// Derive sample type.
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sample := 1
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if _type != 0 {
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sample = 2
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}
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// Derive matrix number.
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mtxNo := 0
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if nbqTab == 2 {
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mtxNo = 1
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}
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b = make([]byte, 17)
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p = putter{}
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p.put16(b, 17)
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p.put8(b, 8)
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p.put16(b, uint16(height))
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p.put16(b, uint16(width))
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p.put8(b, 3)
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p.put8(b, 1)
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p.put8(b, uint8((2<<4)|sample))
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p.put8(b, 0)
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p.put8(b, 2)
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p.put8(b, 1<<4|1)
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p.put8(b, uint8(mtxNo))
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p.put8(b, 3)
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p.put8(b, 1<<4|1)
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p.put8(b, uint8(mtxNo))
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_, err = w.Write(b)
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if err != nil {
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return fmt.Errorf("could not write SOF0 info: %w", err)
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}
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// Write start of scan.
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err = writeMarker(w, codeSOS)
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if err != nil {
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return fmt.Errorf("could not write SOS marker code: %w", err)
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}
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b = make([]byte, 12)
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p = putter{}
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p.put16(b, 12)
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p.put8(b, 3)
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p.put8(b, 1)
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p.put8(b, 0)
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p.put8(b, 2)
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p.put8(b, 17)
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p.put8(b, 3)
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p.put8(b, 17)
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p.put8(b, 0)
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p.put8(b, 63)
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p.put8(b, 0)
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_, err = w.Write(b)
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if err != nil {
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return fmt.Errorf("could not write SOS info: %w", err)
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}
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return nil
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}
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// writeMarker writes an JPEG marker with code to w.
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func writeMarker(w io.Writer, code byte) error {
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_, err := w.Write([]byte{0xff, code})
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if err != nil {
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return err
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}
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return nil
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}
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// writeHuffman write a JPEG huffman table to w.
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func writeHuffman(w io.Writer, class, id int, bits, values []byte) error {
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_, err := w.Write([]byte{byte(class<<4 | id)})
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if err != nil {
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return fmt.Errorf("could not write class and id: %w", err)
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}
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var n int
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for i := 1; i <= 16; i++ {
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n += int(bits[i])
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}
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_, err = w.Write(bits[1:17])
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if err != nil {
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return fmt.Errorf("could not write first lot of huffman bytes: %w", err)
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}
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_, err = w.Write(values[0:n])
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if err != nil {
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return fmt.Errorf("could not write second lot of huffman bytes: %w", err)
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}
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return nil
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}
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