Stu Leak
68df790d27
Major improvements to UnifiedPlayer: 1. GetFrameImage() now works when paused for responsive UI updates 2. Play() method properly starts FFmpeg process 3. Frame display loop runs continuously for smooth video display 4. Disabled audio temporarily to fix video playback fundamentals 5. Simplified FFmpeg command to focus on video stream only Player now: - Generates video frames correctly - Shows video when paused - Has responsive progress tracking - Starts playback properly Next steps: Re-enable audio playback once video is stable
103 lines
2.3 KiB
Go
103 lines
2.3 KiB
Go
// Copyright 2019 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package ccitt
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import (
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"encoding/binary"
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"io"
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)
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type bitWriter struct {
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w io.Writer
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// order is whether to process w's bytes LSB first or MSB first.
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order Order
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// The high nBits bits of the bits field hold encoded bits to be written to w.
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bits uint64
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nBits uint32
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// bytes[:bw] holds encoded bytes not yet written to w.
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// Overflow protection is ensured by using a multiple of 8 as bytes length.
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bw uint32
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bytes [1024]uint8
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}
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// flushBits copies 64 bits from b.bits to b.bytes. If b.bytes is then full, it
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// is written to b.w.
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func (b *bitWriter) flushBits() error {
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binary.BigEndian.PutUint64(b.bytes[b.bw:], b.bits)
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b.bits = 0
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b.nBits = 0
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b.bw += 8
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if b.bw < uint32(len(b.bytes)) {
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return nil
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}
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b.bw = 0
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if b.order != MSB {
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reverseBitsWithinBytes(b.bytes[:])
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}
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_, err := b.w.Write(b.bytes[:])
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return err
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}
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// close finalizes a bitcode stream by writing any
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// pending bits to bitWriter's underlying io.Writer.
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func (b *bitWriter) close() error {
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// Write any encoded bits to bytes.
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if b.nBits > 0 {
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binary.BigEndian.PutUint64(b.bytes[b.bw:], b.bits)
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b.bw += (b.nBits + 7) >> 3
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}
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if b.order != MSB {
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reverseBitsWithinBytes(b.bytes[:b.bw])
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}
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// Write b.bw bytes to b.w.
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_, err := b.w.Write(b.bytes[:b.bw])
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return err
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}
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// alignToByteBoundary rounds b.nBits up to a multiple of 8.
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// If all 64 bits are used, flush them to bitWriter's bytes.
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func (b *bitWriter) alignToByteBoundary() error {
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if b.nBits = (b.nBits + 7) &^ 7; b.nBits == 64 {
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return b.flushBits()
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}
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return nil
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}
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// writeCode writes a variable length bitcode to b's underlying io.Writer.
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func (b *bitWriter) writeCode(bs bitString) error {
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bits := bs.bits
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nBits := bs.nBits
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if 64-b.nBits >= nBits {
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// b.bits has sufficient room for storing nBits bits.
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b.bits |= uint64(bits) << (64 - nBits - b.nBits)
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b.nBits += nBits
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if b.nBits == 64 {
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return b.flushBits()
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}
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return nil
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}
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// Number of leading bits that fill b.bits.
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i := 64 - b.nBits
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// Fill b.bits then flush and write remaining bits.
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b.bits |= uint64(bits) >> (nBits - i)
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b.nBits = 64
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if err := b.flushBits(); err != nil {
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return err
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}
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nBits -= i
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b.bits = uint64(bits) << (64 - nBits)
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b.nBits = nBits
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return nil
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}
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