ffmpeg | branch: master | Andreas Rheinhardt <andreas.rheinhardt@outlook.com> | Tue Sep 26 18:36:38 2023 +0200| [c9aa80c313911b9ac44ab8099bdcc612796c6b90] | committer: Andreas Rheinhardt avcodec/mpegaudiodec_common: Avoid superfluous VLC structures For some VLCs here, the number of bits of the VLC is write-only, because it is hardcoded at the call site. Therefore one can replace these VLC structures with the only thing that is actually used: The pointer to the VLCElem table. Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=c9aa80c313911b9ac4...
libavcodec/mpegaudiodata.h | 2 +- libavcodec/mpegaudiodec_common.c | 16 +++++++--------- libavcodec/mpegaudiodec_template.c | 5 +++-- 3 files changed, 11 insertions(+), 12 deletions(-) diff --git a/libavcodec/mpegaudiodata.h b/libavcodec/mpegaudiodata.h index a4148a1ffe..fbad67a0b3 100644 --- a/libavcodec/mpegaudiodata.h +++ b/libavcodec/mpegaudiodata.h @@ -53,7 +53,7 @@ extern uint32_t ff_table_4_3_value[TABLE_4_3_SIZE]; #endif /* VLCs for decoding layer 3 huffman tables */ -extern VLC ff_huff_vlc[16]; +extern const VLCElem *ff_huff_vlc[16]; extern VLC ff_huff_quad_vlc[2]; /* layer3 scale factor size */ diff --git a/libavcodec/mpegaudiodec_common.c b/libavcodec/mpegaudiodec_common.c index 3a60b03e9e..6446d08967 100644 --- a/libavcodec/mpegaudiodec_common.c +++ b/libavcodec/mpegaudiodec_common.c @@ -64,7 +64,7 @@ const uint8_t ff_lsf_nsf_table[6][3][4] = { }; /* mpegaudio layer 3 huffman tables */ -VLC ff_huff_vlc[16]; +const VLCElem *ff_huff_vlc[16]; static VLCElem huff_vlc_tables[128 + 128 + 128 + 130 + 128 + 154 + 166 + 142 + 204 + 190 + 170 + 542 + 460 + 662 + 414]; VLC ff_huff_quad_vlc[2]; @@ -401,6 +401,7 @@ const uint8_t ff_mpa_pretab[2][22] = { static av_cold void mpegaudiodec_common_init_static(void) { + VLCInitState state = VLC_INIT_STATE(huff_vlc_tables); const uint8_t *huff_sym = mpa_huffsymbols, *huff_lens = mpa_hufflens; int offset; @@ -414,7 +415,6 @@ static av_cold void mpegaudiodec_common_init_static(void) } /* huffman decode tables */ - offset = 0; for (int i = 0; i < 15;) { uint16_t tmp_symbols[256]; int nb_codes_minus_one = mpa_huff_sizes_minus_one[i]; @@ -426,16 +426,14 @@ static av_cold void mpegaudiodec_common_init_static(void) tmp_symbols[j] = high << 1 | ((high && low) << 4) | low; } - ff_huff_vlc[++i].table = huff_vlc_tables + offset; - ff_huff_vlc[i].table_allocated = FF_ARRAY_ELEMS(huff_vlc_tables) - offset; - ff_vlc_init_from_lengths(&ff_huff_vlc[i], 7, j, - huff_lens, 1, tmp_symbols, 2, 2, - 0, VLC_INIT_STATIC_OVERLONG, NULL); - offset += ff_huff_vlc[i].table_size; + ff_huff_vlc[++i] = ff_vlc_init_tables_from_lengths(&state, 7, j, + huff_lens, 1, + tmp_symbols, 2, 2, + 0, 0); huff_lens += j; huff_sym += j; } - av_assert0(offset == FF_ARRAY_ELEMS(huff_vlc_tables)); + av_assert1(state.size == 0); offset = 0; for (int i = 0; i < 2; i++) { diff --git a/libavcodec/mpegaudiodec_template.c b/libavcodec/mpegaudiodec_template.c index 3e4ee79be6..c227604107 100644 --- a/libavcodec/mpegaudiodec_template.c +++ b/libavcodec/mpegaudiodec_template.c @@ -760,6 +760,7 @@ static int huffman_decode(MPADecodeContext *s, GranuleDef *g, /* low frequencies (called big values) */ s_index = 0; for (i = 0; i < 3; i++) { + const VLCElem *vlctab; int j, k, l, linbits; j = g->region_size[i]; if (j == 0) @@ -768,13 +769,13 @@ static int huffman_decode(MPADecodeContext *s, GranuleDef *g, k = g->table_select[i]; l = ff_mpa_huff_data[k][0]; linbits = ff_mpa_huff_data[k][1]; - vlc = &ff_huff_vlc[l]; if (!l) { memset(&g->sb_hybrid[s_index], 0, sizeof(*g->sb_hybrid) * 2 * j); s_index += 2 * j; continue; } + vlctab = ff_huff_vlc[l]; /* read huffcode and compute each couple */ for (; j > 0; j--) { @@ -787,7 +788,7 @@ static int huffman_decode(MPADecodeContext *s, GranuleDef *g, if (pos >= end_pos) break; } - y = get_vlc2(&s->gb, vlc->table, 7, 3); + y = get_vlc2(&s->gb, vlctab, 7, 3); if (!y) { g->sb_hybrid[s_index ] =