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jxl-modular: Detect LZ77 bug case #271

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merged 2 commits into from
Mar 4, 2024
Merged

jxl-modular: Detect LZ77 bug case #271

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717b67f
jxl-modular: Detect LZ77 bug case
tirr-c Mar 3, 2024
a025011
jxl-modular: Try better detection method
tirr-c Mar 3, 2024
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54 changes: 46 additions & 8 deletions crates/jxl-modular/src/image.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -514,8 +514,51 @@ impl<'dest, S: Sample> TransformedModularSubimage<'dest, S> {
decoder.finalize()?;
return Ok(());
}
if let Some(lz77_decoder) = decoder.as_with_lz77() {
self.decode_image_lz77(bitstream, stream_index, lz77_decoder)?;
if decoder.as_with_lz77().is_some() {
let dist_multiplier = self
.channel_info
.iter()
.skip(self.nb_meta_channels)
.map(|info| info.width)
.max()
.unwrap_or(0);
let dist_multiplier_legacy = self
.channel_info
.iter()
.map(|info| info.width)
.max()
.unwrap_or(0);

if dist_multiplier == dist_multiplier_legacy {
let lz77_decoder = decoder.as_with_lz77().unwrap();
self.decode_image_lz77(bitstream, stream_index, lz77_decoder, dist_multiplier)?;
decoder.finalize()?;
return Ok(());
}

let tmp_bitstream = bitstream.clone();
let tmp_decoder = decoder.clone();

// Try standard method first
let lz77_decoder = decoder.as_with_lz77().unwrap();
let result =
self.decode_image_lz77(bitstream, stream_index, lz77_decoder, dist_multiplier);
if result.is_ok() && decoder.finalize().is_ok() {
return Ok(());
}

// Decode error with standard method
tracing::warn!("Invalid LZ77 stream, trying legacy method");
*bitstream = tmp_bitstream;
let mut decoder = tmp_decoder;

let lz77_decoder = decoder.as_with_lz77().unwrap();
self.decode_image_lz77(
bitstream,
stream_index,
lz77_decoder,
dist_multiplier_legacy,
)?;
decoder.finalize()?;
return Ok(());
}
Expand Down Expand Up @@ -623,13 +666,8 @@ impl<'dest, S: Sample> TransformedModularSubimage<'dest, S> {
bitstream: &mut Bitstream,
stream_index: u32,
mut decoder: DecoderWithLz77<'_>,
dist_multiplier: u32,
) -> Result<()> {
let dist_multiplier = self
.channel_info
.iter()
.map(|info| info.width)
.max()
.unwrap_or(0);
let mut next = |cluster: u8| -> Result<i32> {
let token = decoder.read_varint_with_multiplier_clustered(
bitstream,
Expand Down