oops. forgot to commit the new file

git-svn-id: svn://svn.handbrake.fr/HandBrake/trunk@3343 b64f7644-9d1e-0410-96f1-a4d463321fa5

1 files changed, 269 insertions, 0 deletions

diff --git a/libhb/decssasub.c b/libhb/decssasub.c
new file mode 100644
index 000000000..e4ff0dc59
--- /dev/null
+++ b/libhb/decssasub.c
@@ -0,0 +1,269 @@
+/* 
+   This file is part of the HandBrake source code.
+   Homepage: <http://handbrake.fr/>.
+   It may be used under the terms of the GNU General Public License. */
+
+/*
+ * Converts SSA subtitles to UTF-8 subtitles with limited HTML-style markup (<b>, <i>, <u>).
+ * 
+ * SSA format references:
+ *   http://www.matroska.org/technical/specs/subtitles/ssa.html
+ *   http://moodub.free.fr/video/ass-specs.doc
+ *   vlc-1.0.4/modules/codec/subtitles/subsass.c:ParseSSAString
+ * 
+ * @author David Foster (davidfstr)
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include "hb.h"
+
+typedef enum {
+    BOLD        = 0x01,
+    ITALIC      = 0x02,
+    UNDERLINE   = 0x04
+} StyleSet;
+
+// "<b></b>".len + "<i></i>".len + "<u></u>".len
+#define MAX_OVERHEAD_PER_OVERRIDE (7 * 3)
+
+#define SSA_2_HB_TIME(hr,min,sec,centi) \
+    ( 90L * ( hr    * 1000L * 60 * 60 +\
+              min   * 1000L * 60 +\
+              sec   * 1000L +\
+              centi * 10L ) )
+
+static StyleSet ssa_parse_style_override( char *pos, StyleSet prevStyles )
+{
+    StyleSet nextStyles = prevStyles;
+    for (;;)
+    {
+        // Skip over leading '{' or last '\\'
+        pos++;
+        
+        // Scan for next \code
+        while ( *pos != '\\' && *pos != '}' && *pos != '\0' ) pos++;
+        if ( *pos != '\\' )
+        {
+            // End of style override block
+            break;
+        }
+        
+        // If next chars are \[biu][01], interpret it
+        if ( strchr("biu", pos[1]) && strchr("01", pos[2]) )
+        {
+            StyleSet styleID =
+                pos[1] == 'b' ? BOLD :
+                pos[1] == 'i' ? ITALIC :
+                pos[1] == 'u' ? UNDERLINE : 0;
+            int enabled = (pos[2] == '1');
+            
+            if (enabled)
+            {
+                nextStyles |= styleID;
+            }
+            else
+            {
+                nextStyles &= ~styleID;
+            }
+        }
+    }
+    return nextStyles;
+}
+
+static void ssa_append_html_tags_for_style_change(
+    char **dst, StyleSet prevStyles, StyleSet nextStyles )
+{
+    #define APPEND(str) { \
+        char *src = str; \
+        while (*src) { *(*dst)++ = *src++; } \
+    }
+
+    // Reverse-order close all previous styles
+    if (prevStyles & UNDERLINE) APPEND("</u>");
+    if (prevStyles & ITALIC)    APPEND("</i>");
+    if (prevStyles & BOLD)      APPEND("</b>");
+    
+    // Forward-order open all next styles
+    if (nextStyles & BOLD)      APPEND("<b>");
+    if (nextStyles & ITALIC)    APPEND("<i>");
+    if (nextStyles & UNDERLINE) APPEND("<u>");
+    
+    #undef APPEND
+}
+
+/*
+ * SSA packet format:
+ *   Dialogue: Marked,Start,End,Style,Name,MarginL,MarginR,MarginV,Effect,Text
+ *             1      2     3   4     5    6       7       8       9      10
+ */
+static hb_buffer_t *ssa_decode_to_utf8( hb_buffer_t *in )
+{
+    uint8_t *pos = in->data;
+    uint8_t *end = in->data + in->size;
+    
+    // Store NULL after the end of the buffer to make using sscanf safe
+    hb_buffer_realloc( in, in->size + 1 );
+    in->data[in->size] = '\0';
+    
+    /*
+     * Parse Start and End fields for timing information
+     */
+    int start_hr, start_min, start_sec, start_centi;
+    int   end_hr,   end_min,   end_sec,   end_centi;
+    int numPartsRead = sscanf( (char *) in->data, "%*128[^,],"
+        "%d:%d:%d.%d,"  // Start
+        "%d:%d:%d.%d,", // End
+        &start_hr, &start_min, &start_sec, &start_centi,
+          &end_hr,   &end_min,   &end_sec,   &end_centi );
+    if ( numPartsRead != 8 )
+        goto fail;
+    
+    in->start = SSA_2_HB_TIME(start_hr, start_min, start_sec, start_centi);
+    in->stop  = SSA_2_HB_TIME(  end_hr,   end_min,   end_sec,   end_centi);
+    
+    /*
+     * Advance 'pos' to the beginning of the Text field
+     */
+    int curFieldID = 1;
+    while (pos < end)
+    {
+        if ( *pos++ == ',' )
+        {
+            curFieldID++;
+            if ( curFieldID == 10 ) // Text
+                break;
+        }
+    }
+    if ( curFieldID != 10 )
+        goto fail;
+    uint8_t *textFieldPos = pos;
+    
+    // Count the number of style overrides in the Text field
+    int numStyleOverrides = 0;
+    while ( pos < end )
+    {
+        if (*pos++ == '{')
+        {
+            numStyleOverrides++;
+        }
+    }
+    
+    int maxOutputSize = (end - pos) + ((numStyleOverrides + 1) * MAX_OVERHEAD_PER_OVERRIDE);
+    hb_buffer_t *out = hb_buffer_init( maxOutputSize );
+    if ( out == NULL )
+        return NULL;
+    
+    /*
+     * The Text field contains plain text marked up with:
+     * (1) '\n' -> space
+     * (2) '\N' -> newline
+     * (3) curly-brace control codes like '{\k44}' -> empty (strip them)
+     * 
+     * Perform the above conversions and copy it to the output packet
+     */
+    StyleSet prevStyles = 0;
+    uint8_t *dst = out->data;
+    pos = textFieldPos;
+    while ( pos < end )
+    {
+        if ( pos[0] == '\\' && pos[1] == 'n' )
+        {
+            *dst++ = ' ';
+            pos += 2;
+        }
+        else if ( pos[0] == '\\' && pos[1] == 'N' )
+        {
+            *dst++ = '\n';
+            pos += 2;
+        }
+        else if ( pos[0] == '{' )
+        {
+            // Parse SSA style overrides and append appropriate HTML style tags
+            StyleSet nextStyles = ssa_parse_style_override( pos, prevStyles );
+            ssa_append_html_tags_for_style_change( &dst, prevStyles, nextStyles );
+            prevStyles = nextStyles;
+            
+            // Skip past SSA control code
+            while ( pos < end && *pos != '}' ) pos++;
+            if    ( pos < end && *pos == '}' ) pos++;
+        }
+        else
+        {
+            // Copy raw character
+            *dst++ = *pos++;
+        }
+    }
+    
+    // Append closing HTML style tags
+    ssa_append_html_tags_for_style_change( &dst, prevStyles, 0 );
+    
+    // Trim output buffer to the actual amount of data written
+    out->size = dst - out->data;
+    
+    // Copy metadata from the input packet to the output packet
+    out->start = in->start;
+    out->stop = in->stop;
+    
+    return out;
+    
+fail:
+    hb_log( "decssasub: malformed SSA subtitle packet: %.*s\n", in->size, in->data );
+    return NULL;
+}
+
+static int decssaInit( hb_work_object_t * w, hb_job_t * job )
+{
+    return 0;
+}
+
+static int decssaWork( hb_work_object_t * w, hb_buffer_t ** buf_in,
+                        hb_buffer_t ** buf_out )
+{
+    hb_buffer_t * in = *buf_in;
+    hb_buffer_t * out = NULL;
+    
+    if ( in->size > 0 ) {
+        out = ssa_decode_to_utf8(in);
+    } else {
+        out = hb_buffer_init( 0 );
+    }
+    
+    if ( out != NULL ) {
+        // We shouldn't be storing the extra NULL character,
+        // but the MP4 muxer expects this, unfortunately.
+        if ( out->size > 0 && out->data[out->size - 1] != '\0' ) {
+            // NOTE: out->size remains unchanged
+            hb_buffer_realloc( out, out->size + 1 );
+            out->data[out->size] = '\0';
+        }
+        
+        // If the input packet was non-empty, do not pass through
+        // an empty output packet (even if the subtitle was empty),
+        // as this would be interpreted as an end-of-stream
+        if ( in->size > 0 && out->size == 0 ) {
+            hb_buffer_close(&out);
+        }
+    }
+    
+    // Dispose the input packet, as it is no longer needed
+    hb_buffer_close(&in);
+    
+    *buf_in = NULL;
+    *buf_out = out;
+    return HB_WORK_OK;
+}
+
+static void decssaClose( hb_work_object_t * w )
+{
+    // nothing
+}
+
+hb_work_object_t hb_decssasub =
+{
+    WORK_DECSSASUB,
+    "SSA Subtitle Decoder",
+    decssaInit,
+    decssaWork,
+    decssaClose
+};