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CEA-608 queue rather than stack #21

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merged 2 commits into from
Dec 3, 2024
Merged

CEA-608 queue rather than stack #21

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afa4923
writer: correctly order multiple 608 data across packets
ystreet Dec 2, 2024
04c58c8
writer: fix padding handling
ystreet Dec 2, 2024
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46 changes: 31 additions & 15 deletions src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -306,7 +306,7 @@ impl Framerate {
self.denom
}

fn cea608_pairs_per_field(&self) -> usize {
fn cea608_pairs_per_frame(&self) -> usize {
// CEA-608 has a max bitrate of 960 bits/s for a single field
// TODO: handle alternating counts for 24fps
60.mul_div_round(self.denom, self.numer).unwrap() as usize
Expand All @@ -328,8 +328,8 @@ pub struct CCDataWriter {
packets: VecDeque<DTVCCPacket>,
// part of a packet we could not fit into the previous packet
pending_packet_data: Vec<u8>,
cea608_1: Vec<(u8, u8)>,
cea608_2: Vec<(u8, u8)>,
cea608_1: VecDeque<(u8, u8)>,
cea608_2: VecDeque<(u8, u8)>,
last_cea608_was_field1: bool,
}

Expand Down Expand Up @@ -363,13 +363,13 @@ impl CCDataWriter {
pub fn push_cea608(&mut self, cea608: Cea608) {
match cea608 {
Cea608::Field1(byte0, byte1) => {
if byte0 != 0x80 && byte1 != 0x80 {
self.cea608_1.push((byte0, byte1))
if byte0 != 0x80 || byte1 != 0x80 {
self.cea608_1.push_front((byte0, byte1))
}
}
Cea608::Field2(byte0, byte1) => {
if byte0 != 0x80 && byte1 != 0x80 {
self.cea608_2.push((byte0, byte1))
if byte0 != 0x80 || byte1 != 0x80 {
self.cea608_2.push_front((byte0, byte1))
}
}
}
Expand Down Expand Up @@ -430,10 +430,10 @@ impl CCDataWriter {
w: &mut W,
) -> Result<(), std::io::Error> {
let mut cea608_pair_rem = if self.output_cea608_padding {
framerate.cea608_pairs_per_field()
framerate.cea608_pairs_per_frame()
} else {
framerate
.cea608_pairs_per_field()
.cea608_pairs_per_frame()
.min(self.cea608_1.len().max(self.cea608_2.len() * 2))
};

Expand All @@ -458,7 +458,7 @@ impl CCDataWriter {
if cea608_pair_rem > 0 {
if !self.last_cea608_was_field1 {
trace!("attempting to write a cea608 byte pair from field 1");
if let Some((byte0, byte1)) = self.cea608_1.pop() {
if let Some((byte0, byte1)) = self.cea608_1.pop_back() {
w.write_all(&[0xFC, byte0, byte1])?;
cc_count_rem -= 1;
} else if !self.cea608_2.is_empty() {
Expand All @@ -472,7 +472,7 @@ impl CCDataWriter {
self.last_cea608_was_field1 = true;
} else {
trace!("attempting to write a cea608 byte pair from field 2");
if let Some((byte0, byte1)) = self.cea608_2.pop() {
if let Some((byte0, byte1)) = self.cea608_2.pop_back() {
w.write_all(&[0xFD, byte0, byte1])?;
cc_count_rem -= 1;
} else if self.output_cea608_padding {
Expand Down Expand Up @@ -1231,7 +1231,7 @@ mod test {
}
}

static WRITE_CC_DATA: [TestCCData; 6] = [
static WRITE_CC_DATA: [TestCCData; 7] = [
// simple packet with a single service and single code
TestCCData {
framerate: Framerate::new(25, 1),
Expand Down Expand Up @@ -1482,6 +1482,22 @@ mod test {
}],
cea608: &[&[Cea608::Field1(0x20, 0x42), Cea608::Field2(0x21, 0x43)]],
},
// simple packet with multiple cea608 that will span two outputs
TestCCData {
framerate: Framerate::new(24, 1),
cc_data: &[
&[0x80 | 0x40 | 0x02, 0xFF, 0xFC, 0x20, 0x42, 0xFD, 0x21, 0x43],
&[0x80 | 0x40 | 0x02, 0xFF, 0xFC, 0x22, 0x44, 0xFD, 0x23, 0x45],
],
packets: &[PacketData {
sequence_no: 3,
services: &[],
}],
cea608: &[
&[Cea608::Field1(0x20, 0x42), Cea608::Field2(0x21, 0x43)],
&[Cea608::Field1(0x22, 0x44), Cea608::Field2(0x23, 0x45)],
],
},
];

#[test]
Expand Down Expand Up @@ -1517,9 +1533,9 @@ mod test {
}

#[test]
fn framerate_cea608_pairs_per_field() {
assert_eq!(Framerate::new(60, 1).cea608_pairs_per_field(), 1);
assert_eq!(Framerate::new(30, 1).cea608_pairs_per_field(), 2);
fn framerate_cea608_pairs_per_frame() {
assert_eq!(Framerate::new(60, 1).cea608_pairs_per_frame(), 1);
assert_eq!(Framerate::new(30, 1).cea608_pairs_per_frame(), 2);
}

#[test]
Expand Down
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