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https://github.com/storytold/filmcraft.git
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Logan JenningsandClaude Opus 4.7
cb2ac66c3b
- av1: a 4:2:2 stream (profile bit flipped) could reach blocks with no chroma size (BLOCK_INVALID) and index MAX_TX_SIZE_RECT out of bounds; reject them with an error in decode_block. - av1: frame size accepted up to 65536x65536 (gigabytes of buffers from a few header bytes); cap at 16384 per side and 2^27 samples. - mpeg2v: 16383x16383 4:4:4 sequences (gigabytes per picture) are refused; area capped at 2^25. - fuzz_hostile tests (truncation, header byte/bit sweeps, random mutation) for h264, hevc, vp8, vp9, av1, mpeg2v, apv, prores and dnx; ffmpeg-based ones skip without ffmpeg. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
74 lines
2.1 KiB
Rust
74 lines
2.1 KiB
Rust
//! A 14-byte sequence header must not make the decoder size its frame buffers at 16383 x 16383
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//! (gigabytes per picture). Hand-built, no ffmpeg.
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use filmcraft_mpeg2v::Decoder;
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#[derive(Default)]
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struct Bits {
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bytes: Vec<u8>,
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n: usize,
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}
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impl Bits {
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fn put(&mut self, value: u32, bits: usize) {
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for i in (0..bits).rev() {
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if self.n.is_multiple_of(8) {
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self.bytes.push(0);
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}
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if (value >> i) & 1 == 1
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&& let Some(b) = self.bytes.last_mut()
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{
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*b |= 0x80 >> (self.n % 8);
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}
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self.n += 1;
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}
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}
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}
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/// Sequence header plus sequence extension for a `w` x `h` 4:4:4 stream.
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fn sequence(w: u32, h: u32, chroma_format: u32) -> Vec<u8> {
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let mut s = Bits::default();
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s.put(w & 0xfff, 12);
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s.put(h & 0xfff, 12);
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s.put(1, 4); // aspect_ratio_information
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s.put(4, 4); // frame_rate_code
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s.put(1000, 18); // bit_rate_value
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s.put(1, 1); // marker
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s.put(100, 10); // vbv_buffer_size_value
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s.put(0, 3); // constrained_parameters_flag, load_intra, load_non_intra
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let mut e = Bits::default();
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e.put(1, 4); // sequence_extension
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e.put(0x48, 8); // profile_and_level_indication
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e.put(1, 1); // progressive_sequence
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e.put(chroma_format, 2);
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e.put(w >> 12, 2);
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e.put(h >> 12, 2);
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e.put(0, 12); // bit_rate_extension
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e.put(1, 1); // marker
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e.put(0, 8 + 1 + 2 + 5); // vbv_buffer_size_extension, low_delay, frame_rate_extension_n/d
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let mut out = vec![0, 0, 1, 0xb3];
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out.extend(s.bytes);
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out.extend([0, 0, 1, 0xb5]);
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out.extend(e.bytes);
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out
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}
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fn accepted(w: u32, h: u32, chroma_format: u32) -> bool {
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let mut dec = Decoder::new();
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let _ = dec.decode(&sequence(w, h, chroma_format), 0);
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dec.sequence().is_some()
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}
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#[test]
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fn ordinary_sequences_are_accepted() {
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assert!(accepted(1920, 1080, 1));
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assert!(accepted(7680, 4320, 3));
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}
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#[test]
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fn gigantic_sequences_are_refused() {
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assert!(!accepted(16383, 16383, 3));
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assert!(!accepted(16383, 16383, 1));
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assert!(!accepted(8192, 8192, 1));
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}
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