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https://github.com/FFmpeg/FFmpeg.git
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AAC: optimise bitstream reading in decode_spectrum_and_dequant()
Using the low-level macros directly avoids redundant open/update/close cycles. 2-3% faster on ARM, PPC, and Core i7. Originally committed as revision 21224 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Måns Rullgård
parent
59ea69ef54
commit
d356a53f44
@ -993,6 +993,7 @@ static int decode_spectrum_and_dequant(AACContext *ac, float coef[1024],
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const uint16_t *cb_vector_idx = ff_aac_codebook_vector_idx[cbt_m1];
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VLC_TYPE (*vlc_tab)[2] = vlc_spectral[cbt_m1].table;
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const int cb_size = ff_aac_spectral_sizes[cbt_m1];
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OPEN_READER(re, gb);
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switch (cbt_m1 >> 1) {
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case 0:
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@ -1001,15 +1002,18 @@ static int decode_spectrum_and_dequant(AACContext *ac, float coef[1024],
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int len = off_len;
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do {
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const int index = get_vlc2(gb, vlc_tab, 8, 2);
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int code;
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unsigned cb_idx;
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if (index >= cb_size) {
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err_idx = index;
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UPDATE_CACHE(re, gb);
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GET_VLC(code, re, gb, vlc_tab, 8, 2);
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if (code >= cb_size) {
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err_idx = code;
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goto err_cb_overflow;
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}
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cb_idx = cb_vector_idx[index];
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cb_idx = cb_vector_idx[code];
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cf = VMUL4(cf, vq, cb_idx, sf + idx);
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} while (len -= 4);
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}
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@ -1021,19 +1025,26 @@ static int decode_spectrum_and_dequant(AACContext *ac, float coef[1024],
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int len = off_len;
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do {
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const int index = get_vlc2(gb, vlc_tab, 8, 2);
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int code;
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unsigned nnz;
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unsigned cb_idx;
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uint32_t bits;
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if (index >= cb_size) {
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err_idx = index;
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UPDATE_CACHE(re, gb);
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GET_VLC(code, re, gb, vlc_tab, 8, 2);
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if (code >= cb_size) {
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err_idx = code;
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goto err_cb_overflow;
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}
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cb_idx = cb_vector_idx[index];
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#if MIN_CACHE_BITS < 20
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UPDATE_CACHE(re, gb);
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#endif
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cb_idx = cb_vector_idx[code];
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nnz = cb_idx >> 8 & 15;
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bits = get_bits(gb, nnz) << (32-nnz);
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bits = SHOW_UBITS(re, gb, nnz) << (32-nnz);
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LAST_SKIP_BITS(re, gb, nnz);
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cf = VMUL4S(cf, vq, cb_idx, bits, sf + idx);
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} while (len -= 4);
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}
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@ -1045,15 +1056,18 @@ static int decode_spectrum_and_dequant(AACContext *ac, float coef[1024],
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int len = off_len;
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do {
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const int index = get_vlc2(gb, vlc_tab, 8, 2);
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int code;
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unsigned cb_idx;
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if (index >= cb_size) {
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err_idx = index;
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UPDATE_CACHE(re, gb);
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GET_VLC(code, re, gb, vlc_tab, 8, 2);
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if (code >= cb_size) {
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err_idx = code;
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goto err_cb_overflow;
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}
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cb_idx = cb_vector_idx[index];
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cb_idx = cb_vector_idx[code];
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cf = VMUL2(cf, vq, cb_idx, sf + idx);
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} while (len -= 2);
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}
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@ -1066,19 +1080,23 @@ static int decode_spectrum_and_dequant(AACContext *ac, float coef[1024],
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int len = off_len;
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do {
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const int index = get_vlc2(gb, vlc_tab, 8, 2);
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int code;
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unsigned nnz;
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unsigned cb_idx;
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unsigned sign;
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if (index >= cb_size) {
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err_idx = index;
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UPDATE_CACHE(re, gb);
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GET_VLC(code, re, gb, vlc_tab, 8, 2);
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if (code >= cb_size) {
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err_idx = code;
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goto err_cb_overflow;
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}
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cb_idx = cb_vector_idx[index];
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cb_idx = cb_vector_idx[code];
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nnz = cb_idx >> 8 & 15;
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sign = get_bits(gb, nnz) << (cb_idx >> 12);
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sign = SHOW_UBITS(re, gb, nnz) << (cb_idx >> 12);
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LAST_SKIP_BITS(re, gb, nnz);
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cf = VMUL2S(cf, vq, cb_idx, sign, sf + idx);
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} while (len -= 2);
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}
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@ -1091,39 +1109,56 @@ static int decode_spectrum_and_dequant(AACContext *ac, float coef[1024],
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int len = off_len;
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do {
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const int index = get_vlc2(gb, vlc_tab, 8, 2);
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int code;
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unsigned nzt, nnz;
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unsigned cb_idx;
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uint32_t bits;
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int j;
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if (!index) {
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UPDATE_CACHE(re, gb);
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GET_VLC(code, re, gb, vlc_tab, 8, 2);
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if (!code) {
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*icf++ = 0;
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*icf++ = 0;
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continue;
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}
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if (index >= cb_size) {
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err_idx = index;
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if (code >= cb_size) {
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err_idx = code;
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goto err_cb_overflow;
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}
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cb_idx = cb_vector_idx[index];
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cb_idx = cb_vector_idx[code];
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nnz = cb_idx >> 12;
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nzt = cb_idx >> 8;
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bits = get_bits(gb, nnz) << (32-nnz);
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bits = SHOW_UBITS(re, gb, nnz) << (32-nnz);
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LAST_SKIP_BITS(re, gb, nnz);
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for (j = 0; j < 2; j++) {
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if (nzt & 1<<j) {
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int n = 4;
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uint32_t b;
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int n;
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/* The total length of escape_sequence must be < 22 bits according
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to the specification (i.e. max is 111111110xxxxxxxxxxxx). */
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while (get_bits1(gb) && n < 13) n++;
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if (n == 13) {
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UPDATE_CACHE(re, gb);
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b = GET_CACHE(re, gb);
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b = 31 - av_log2(~b);
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if (b > 8) {
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av_log(ac->avccontext, AV_LOG_ERROR, "error in spectral data, ESC overflow\n");
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return -1;
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}
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n = (1 << n) + get_bits(gb, n);
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#if MIN_CACHE_BITS < 21
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LAST_SKIP_BITS(re, gb, b + 1);
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UPDATE_CACHE(re, gb);
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#else
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SKIP_BITS(re, gb, b + 1);
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#endif
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b += 4;
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n = (1 << b) + SHOW_UBITS(re, gb, b);
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LAST_SKIP_BITS(re, gb, b);
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*icf++ = cbrt_tab[n] | (bits & 1<<31);
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bits <<= 1;
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} else {
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@ -1138,6 +1173,8 @@ static int decode_spectrum_and_dequant(AACContext *ac, float coef[1024],
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ac->dsp.vector_fmul_scalar(cfo, cfo, sf[idx], off_len);
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}
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}
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CLOSE_READER(re, gb);
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}
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}
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coef += g_len << 7;
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