Add TXTH padding_size = (value|auto|auto-empty) to skip PS-ADPCM padding

src/coding/coding.h

@@ -84,6 +84,7 @@ void decode_psx(VGMSTREAMCHANNEL * stream, sample_t * outbuf, int channelspacing
 void decode_psx_configurable(VGMSTREAMCHANNEL * stream, sample_t * outbuf, int channelspacing, int32_t first_sample, int32_t samples_to_do, int frame_size);
 int ps_find_loop_offsets(STREAMFILE *streamFile, off_t start_offset, size_t data_size, int channels, size_t interleave, int32_t * out_loop_start, int32_t * out_loop_end);
 int ps_find_loop_offsets_full(STREAMFILE *streamFile, off_t start_offset, size_t data_size, int channels, size_t interleave, int32_t * out_loop_start, int32_t * out_loop_end);
+size_t ps_find_padding(STREAMFILE *streamFile, off_t start_offset, size_t data_size, int channels, size_t interleave, int discard_empty);
 size_t ps_bytes_to_samples(size_t bytes, int channels);
 size_t ps_cfg_bytes_to_samples(size_t bytes, size_t frame_size, int channels);
 

src/coding/psx_decoder.c

@@ -176,6 +176,9 @@ static int ps_find_loop_offsets_internal(STREAMFILE *streamFile, off_t start_off
     int detect_full_loops = config & 1;
 
 
+    if (data_size == 0 || channels == 0 || (channels > 0 && interleave == 0))
+        return 0;
+
     while (offset < max_offset) {
         uint8_t flag = (uint8_t)read_8bit(offset+0x01,streamFile) & 0x0F; /* lower nibble only (for HEVAG) */
 
@@ -268,6 +271,63 @@ int ps_find_loop_offsets_full(STREAMFILE *streamFile, off_t start_offset, size_t
     return ps_find_loop_offsets_internal(streamFile, start_offset, data_size, channels, interleave, out_loop_start, out_loop_end, 1);
 }
 
+size_t ps_find_padding(STREAMFILE *streamFile, off_t start_offset, size_t data_size, int channels, size_t interleave, int discard_empty) {
+    off_t min_offset, offset;
+    size_t frame_size = 0x10;
+    size_t padding_size = 0;
+    size_t interleave_consumed = 0;
+
+
+    if (data_size == 0 || channels == 0 || (channels > 0 && interleave == 0))
+        return 0;
+
+    offset = start_offset + data_size;
+    min_offset = 0; //offset - interleave; /* some files have padding spanning multiple interleave blocks */
+
+    while (offset > min_offset) {
+        uint32_t f1,f2,f3,f4;
+        uint8_t flag;
+        int is_empty = 0;
+
+        offset -= frame_size;
+
+        f1 = read_32bitBE(offset+0x00,streamFile);
+        f2 = read_32bitBE(offset+0x04,streamFile);
+        f3 = read_32bitBE(offset+0x08,streamFile);
+        f4 = read_32bitBE(offset+0x0c,streamFile);
+        flag = (f1 >> 16) & 0xFF;
+
+        if (f1 == 0 && f2 == 0 && f3 == 0 && f4 == 0)
+            is_empty = 1;
+
+        if (!is_empty && discard_empty) {
+            if (flag == 0x07 || flag == 0x77)
+                is_empty = 1; /* 'discard frame' flag */
+            else if ((f1 & 0xFF00FFFF) == 0 && f2 == 0 && f3 == 0 && f4 == 0)
+                is_empty = 1; /* silent with flags (typical for looping files) */
+            else if ((f1 & 0xFF00FFFF) == 0x0C000000 && f2 == 0 && f3 == 0 && f4 == 0)
+                is_empty = 1; /* silent (maybe shouldn't ignore flag 0x03?) */
+            else if ((f1 & 0x0000FFFF) == 0x00007777 && f2 == 0x77777777 && f3 ==0x77777777 && f4 == 0x77777777)
+                is_empty = 1; /* silent-ish */
+        }
+
+        if (!is_empty)
+            break;
+
+        padding_size += frame_size * channels;
+
+        /* skip other channels */
+        interleave_consumed += 0x10;
+        if (interleave_consumed == interleave) {
+            interleave_consumed = 0;
+            offset -= interleave*(channels - 1);
+        }
+    }
+
+    return padding_size;
+}
+
+
 size_t ps_bytes_to_samples(size_t bytes, int channels) {
     if (channels <= 0) return 0;
     return bytes / channels / 0x10 * 28;

src/meta/txth.c

@@ -57,6 +57,7 @@ typedef struct {
     uint32_t data_size;
     int data_size_set;
     uint32_t start_offset;
+    uint32_t padding_size;
 
     int sample_type;
     uint32_t num_samples;
@@ -616,6 +617,7 @@ static int parse_coef_table(STREAMFILE * streamFile, txth_header * txth, const c
 static int is_string(const char * val, const char * cmp);
 static int is_substring(const char * val, const char * cmp);
 static int get_bytes_to_samples(txth_header * txth, uint32_t bytes);
+static int get_padding_size(txth_header * txth, int discard_empty);
 
 /* Simple text parser of "key = value" lines.
  * The code is meh and error handling not exactly the best. */
@@ -776,6 +778,8 @@ static int parse_keyval(STREAMFILE * streamFile_, txth_header * txth, const char
     }
     else if (is_string(key,"start_offset")) {
         if (!parse_num(txth->streamHead,txth,val, &txth->start_offset)) goto fail;
+
+        /* apply */
         if (!txth->data_size_set) {
             uint32_t body_size = !txth->streamBody ? 0 : get_streamfile_size(txth->streamBody);
 
@@ -795,6 +799,23 @@ static int parse_keyval(STREAMFILE * streamFile_, txth_header * txth, const char
                 txth->data_size = body_size - txth->start_offset; /* re-evaluate */
         }
     }
+    else if (is_string(key,"padding_size")) {
+        if (is_string(val,"auto")) {
+            txth->padding_size = get_padding_size(txth, 0);
+        }
+        else if (is_string(val,"auto-empty")) {
+            txth->padding_size = get_padding_size(txth, 1);
+        }
+        else {
+            if (!parse_num(txth->streamHead,txth,val, &txth->padding_size)) goto fail;
+        }
+
+        /* apply */
+        if (!txth->data_size_set) {
+            if (txth->padding_size < txth->data_size)
+                txth->data_size -= txth->padding_size;
+        }
+    }
     else if (is_string(key,"data_size")) {
         if (!parse_num(txth->streamHead,txth,val, &txth->data_size)) goto fail;
         txth->data_size_set = 1;
@@ -1262,3 +1283,15 @@ static int get_bytes_to_samples(txth_header * txth, uint32_t bytes) {
             return 0;
     }
 }
+
+static int get_padding_size(txth_header * txth, int discard_empty) {
+    if (txth->data_size == 0 || txth->channels == 0)
+        return 0;
+
+    switch(txth->codec) {
+        case PSX:
+            return ps_find_padding(txth->streamBody, txth->start_offset, txth->data_size, txth->channels, txth->interleave, discard_empty);
+        default:
+            return 0;
+    }
+}