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| author | Andreas Rheinhardt <andreas.rheinhardt@gmail.com> | 2020-11-05 02:29:26 +0100 |
|---|---|---|
| committer | Andreas Rheinhardt <andreas.rheinhardt@gmail.com> | 2020-12-08 17:51:46 +0100 |
| commit | 76a4356a75fd1bb79101ac00bfb73303c369dfc8 (patch) | |
| tree | b83c821922626bb189e2ca8ea460d3ac02ef8dd2 | |
| parent | b52e0d9504d1b45bc64489262facc8e48adb9bc2 (diff) | |
| download | ffmpeg-76a4356a75fd1bb79101ac00bfb73303c369dfc8.tar.gz | |
avcodec/atrac9dec: Don't create VLCs that are never used
The ATRAC9 decoder creates VLCs with parameters contained in
HuffmanCodebooks; some of these HuffmanCodebooks are empty and yet
VLCs (that were completely unused*) were created from them. Said VLC
contained a single table with 512 VLC_TYPE[2] entries, each of which
indicated that this is an invalid code. This commit stops creating said
VLCs.
*: read_coeffs_coarse() uses the HuffmanCodebook
at9_huffman_coeffs[cb][prec][cbi]. prec is c->precision_coarse[i] + 1
and every precision_coarse entry is in the 1..15 range after
calc_precision(), so prec is >= 2 (all codebooks with prec < 2 are
empty). The remaining empty codebooks are those with cb == 1 and cbi ==
0, yet this is impossible, too: cb is given by c->codebookset[i] and
this is always 0 if i < 8 (because those are never set to anything else
in calc_codebook_idx()) and cbi is given by at9_q_unit_to_codebookidx[i]
which is never zero if i >= 8.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
| -rw-r--r-- | libavcodec/atrac9dec.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/libavcodec/atrac9dec.c b/libavcodec/atrac9dec.c index b7a46784fb..c7c6a12f01 100644 --- a/libavcodec/atrac9dec.c +++ b/libavcodec/atrac9dec.c @@ -964,8 +964,8 @@ static av_cold int atrac9_decode_init(AVCodecContext *avctx) /* Coefficient VLCs */ tab = at9_coeffs_tab; for (int i = 0; i < 2; i++) { - for (int j = 0; j < 8; j++) { - for (int k = 0; k < 4; k++) { + for (int j = 2; j < 8; j++) { + for (int k = i; k < 4; k++) { const HuffmanCodebook *hf = &at9_huffman_coeffs[i][j][k]; ret = ff_init_vlc_from_lengths(&s->coeff_vlc[i][j][k], 9, hf->size, &tab[0][1], 2, |