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Cache for MP3 parsing

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- Avoid parsing of MP3 streams that have been parsed before
- For example, improves speed for testfile from issue #37 (before: 90 s,
after: < 1 s)
This commit is contained in:
Christian Schneider 2016-05-06 12:12:36 +02:00
parent e9f370479f
commit 1bf4d71edc
1 changed files with 38 additions and 0 deletions
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38
precomp.cpp
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@ -240,6 +240,9 @@ int idat_count;
long long suppress_mp3_type_until[16];
long long suppress_mp3_big_value_pairs_sum;
long long mp3_parsing_cache_second_frame;
long long mp3_parsing_cache_n;
long long mp3_parsing_cache_mp3_length;
bool fast_mode = false;
bool slow_mode = false;
@ -493,6 +496,7 @@ int init(int argc, char* argv[]) {
suppress_mp3_type_until[i] = -1;
}
suppress_mp3_big_value_pairs_sum = -1;
mp3_parsing_cache_second_frame = -1;
bool valid_syntax = false;
bool input_file_given = false;
@ -3679,6 +3683,8 @@ bool compress_file(float min_percent, float max_percent) {
int padding;
int frame_size;
int n = 0;
long long mp3_parsing_cache_second_frame_candidate = -1;
long long mp3_parsing_cache_second_frame_candidate_size = -1;
long long mp3_length = 0;
@ -3705,6 +3711,10 @@ bool compress_file(float min_percent, float max_percent) {
break;
}
} else {
if (n == 1) {
mp3_parsing_cache_second_frame_candidate = act_pos;
mp3_parsing_cache_second_frame_candidate_size = act_pos - saved_input_file_pos;
}
if (type == MPEG1_LAYER_III) { // supported MP3 type, all header information must be identical to the first frame
if (
(mpeg != ((in[1] >> 3) & 0x3)) ||
@ -3727,6 +3737,21 @@ bool compress_file(float min_percent, float max_percent) {
frame_size = frame_size_table[mpeg][layer][samples][bits];
if (padding) frame_size += (layer == LAYER_I) ? 4 : 1;
// if this frame was part of a stream that already has been parsed, skip parsing
if (n == 0) {
if (act_pos == mp3_parsing_cache_second_frame) {
n = mp3_parsing_cache_n;
mp3_length = mp3_parsing_cache_mp3_length;
// update values
mp3_parsing_cache_second_frame = act_pos + frame_size;
mp3_parsing_cache_n -= 1;
mp3_parsing_cache_mp3_length -= frame_size;
break;
}
}
n++;
mp3_length += frame_size;
act_pos += frame_size;
@ -3747,6 +3772,12 @@ bool compress_file(float min_percent, float max_percent) {
// conditions for proper first frame: 5 consecutive frames
if (n >= 5) {
if (mp3_parsing_cache_second_frame_candidate > -1) {
mp3_parsing_cache_second_frame = mp3_parsing_cache_second_frame_candidate;
mp3_parsing_cache_n = n - 1;
mp3_parsing_cache_mp3_length = mp3_length - mp3_parsing_cache_second_frame_candidate_size;
}
long long position_length_sum = saved_input_file_pos + mp3_length;
// type must be MPEG-1, Layer III, packMP3 won't process any other files
@ -8744,6 +8775,9 @@ void recursion_push() {
recursion_stack_push(&comp_decomp_state, sizeof(comp_decomp_state));
recursion_stack_push(&suppress_mp3_type_until[0], sizeof(suppress_mp3_type_until[0]) * 16);
recursion_stack_push(&suppress_mp3_big_value_pairs_sum, sizeof(suppress_mp3_big_value_pairs_sum));
recursion_stack_push(&mp3_parsing_cache_second_frame, sizeof(mp3_parsing_cache_second_frame));
recursion_stack_push(&mp3_parsing_cache_n, sizeof(mp3_parsing_cache_n));
recursion_stack_push(&mp3_parsing_cache_mp3_length, sizeof(mp3_parsing_cache_mp3_length));
recursion_stack_push(&compression_otf_method, sizeof(compression_otf_method));
recursion_stack_push(&decompress_otf_end, sizeof(decompress_otf_end));
@ -8753,6 +8787,9 @@ void recursion_pop() {
recursion_stack_pop(&decompress_otf_end, sizeof(decompress_otf_end));
recursion_stack_pop(&compression_otf_method, sizeof(compression_otf_method));
recursion_stack_pop(&mp3_parsing_cache_mp3_length, sizeof(mp3_parsing_cache_mp3_length));
recursion_stack_pop(&mp3_parsing_cache_n, sizeof(mp3_parsing_cache_n));
recursion_stack_pop(&mp3_parsing_cache_second_frame, sizeof(mp3_parsing_cache_second_frame));
recursion_stack_pop(&suppress_mp3_big_value_pairs_sum, sizeof(suppress_mp3_big_value_pairs_sum));
recursion_stack_pop(&suppress_mp3_type_until[0], sizeof(suppress_mp3_type_until[0]) * 16);
recursion_stack_pop(&comp_decomp_state, sizeof(comp_decomp_state));
@ -8861,6 +8898,7 @@ recursion_result recursion_compress(int compressed_bytes, int decompressed_bytes
suppress_mp3_type_until[i] = -1;
}
suppress_mp3_big_value_pairs_sum = -1;
mp3_parsing_cache_second_frame = -1;
// disable compression-on-the-fly in recursion - we don't want compressed compressed streams
compression_otf_method = 0;