Commit 288908ed authored by Guillaume Desmottes's avatar Guillaume Desmottes 🐐

cdg: implement typefind

parent 50037325
Pipeline #41182 passed with stages
in 10 minutes and 23 seconds
......@@ -17,10 +17,10 @@ use gst_base::subclass::prelude::*;
use gstreamer::format::Bytes;
use gstreamer_base as gst_base;
use crate::constants::{CDG_HEIGHT, CDG_PACKET_PERIOD, CDG_PACKET_SIZE, CDG_WIDTH};
use crate::constants::{
CDG_COMMAND, CDG_HEIGHT, CDG_MASK, CDG_PACKET_PERIOD, CDG_PACKET_SIZE, CDG_WIDTH,
};
const CDG_MASK: u8 = 0x3F;
const CDG_COMMAND: u8 = 0x09;
const CDG_CMD_MEMORY_PRESET: u8 = 1;
struct CdgParse {
......
......@@ -13,3 +13,6 @@ pub(crate) const CDG_PACKET_PERIOD: u64 = 300;
pub(crate) const CDG_WIDTH: u32 = 300;
pub(crate) const CDG_HEIGHT: u32 = 216;
pub(crate) const CDG_MASK: u8 = 0x3F;
pub(crate) const CDG_COMMAND: u8 = 0x09;
......@@ -17,9 +17,55 @@ mod cdgdec;
mod cdgparse;
mod constants;
use constants::{CDG_COMMAND, CDG_MASK, CDG_PACKET_SIZE};
const TYPEFIND_SEARCH_WINDOW: i64 = 100000; /* in bytes */
/* Return the percentage of CDG packets in the first @len bytes of @typefind */
fn cdg_packets_ratio(typefind: &mut gst::TypeFind, len: i64) -> i64 {
let mut count = 0;
let total = len / CDG_PACKET_SIZE as i64;
for offset in (0..len).step_by(CDG_PACKET_SIZE as usize) {
match typefind.peek(offset, CDG_PACKET_SIZE as u32) {
Some(data) => {
if data[0] & CDG_MASK == CDG_COMMAND {
count += 1;
}
}
None => break,
}
}
(count * 100) / total
}
fn typefind_register(plugin: &gst::Plugin) -> Result<(), glib::BoolError> {
use gst::{Caps, TypeFind, TypeFindProbability};
TypeFind::register(
Some(plugin),
"cdg_typefind",
gst::Rank::None,
Some("cdg"),
Some(&Caps::new_simple("video/x-cdg", &[])),
|mut typefind| {
let proba = match cdg_packets_ratio(&mut typefind, TYPEFIND_SEARCH_WINDOW) {
0...5 => TypeFindProbability::None,
6...10 => TypeFindProbability::Possible,
_ => TypeFindProbability::Likely,
};
if proba != gst::TypeFindProbability::None {
typefind.suggest(proba, &Caps::new_simple("video/x-cdg", &[]));
}
},
)
}
fn plugin_init(plugin: &gst::Plugin) -> Result<(), glib::BoolError> {
cdgdec::register(plugin)?;
cdgparse::register(plugin)?;
typefind_register(plugin)?;
Ok(())
}
......
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