/*
* SSA line format:
* Dialogue: Marked,Start,End,Style,Name,MarginL,MarginR,MarginV,Effect,Text '\0'
* 1 2 3 4 5 6 7 8 9 10
*
* MKV-SSA packet format:
* ReadOrder,Marked, Style,Name,MarginL,MarginR,MarginV,Effect,Text '\0'
* 1 2 3 4 5 6 7 8 9
*/
static hb_buffer_t *
ssa_decode_line_to_mkv_ssa( hb_work_object_t * w, hb_buffer_t * in,
uint8_t *in_data, int in_size )
{
hb_work_private_t * pv = w->private_data;
hb_buffer_t * out;
// Parse values for in->s.start and in->s.stop
int64_t in_start, in_stop;
if ( parse_timing_from_ssa_packet( (char *) in_data, &in_start, &in_stop ) )
goto fail;
// Convert the SSA packet to MKV-SSA format, which is what libass expects
char *mkvIn;
int numPartsRead;
char *styleToTextFields;
char *layerField = malloc( in_size );
// SSA subtitles have an empty layer field (bare ','). The scanf
// format specifier "%*128[^,]" will not match on a bare ','. There
// must be at least one non ',' character in the match. So the format
// specifier is placed directly next to the ':' so that the next
// expected ' ' after the ':' will be the character it matches on
// when there is no layer field.
numPartsRead = sscanf( (char *)in_data, "Dialogue:%128[^,],", layerField );
if ( numPartsRead != 1 )
goto fail;
styleToTextFields = (char *)find_field( in_data, in_data + in_size, 4 );
if ( styleToTextFields == NULL ) {
free( layerField );
goto fail;
}
// The sscanf conversion above will result in an extra space
// before the layerField. Strip the space.
char *stripLayerField = layerField;
for(; *stripLayerField == ' '; stripLayerField++);
out = hb_buffer_init( in_size + 1 );
mkvIn = (char*)out->data;
mkvIn[0] = '\0';
sprintf(mkvIn, "%d", pv->readOrder++); // ReadOrder: make this up
strcat( mkvIn, "," );
strcat( mkvIn, stripLayerField );
strcat( mkvIn, "," );
strcat( mkvIn, (char *)styleToTextFields );
out->size = strlen(mkvIn) + 1;
out->s.frametype = HB_FRAME_SUBTITLE;
out->s.start = in->s.start;
out->s.duration = in_stop - in_start;
out->s.stop = in->s.start + out->s.duration;
out->s.scr_sequence = in->s.scr_sequence;
if( out->size == 0 )
{
hb_buffer_close(&out);
}
free( layerField );
return out;
fail:
hb_log( "decssasub: malformed SSA subtitle packet: %.*s\n", in_size, in_data );
return NULL;
}
/*
* SSA line format:
* Dialogue: Marked,Start,End,Style,Name,MarginL,MarginR,MarginV,Effect,Text '\0'
* 1 2 3 4 5 6 7 8 9 10
*/
static hb_buffer_t *ssa_decode_line_to_utf8( uint8_t *in_data, int in_size, int in_sequence )
{
uint8_t *pos = in_data;
uint8_t *end = in_data + in_size;
// Parse values for in->s.start and in->s.stop
int64_t in_start, in_stop;
if ( parse_timing_from_ssa_packet( (char *) in_data, &in_start, &in_stop ) )
goto fail;
uint8_t *textFieldPos = find_field( pos, end, 10 );
if ( textFieldPos == NULL )
goto fail;
// Count the number of style overrides in the Text field
int numStyleOverrides = 0;
pos = textFieldPos;
while ( pos < end )
{
if (*pos++ == '{')
{
numStyleOverrides++;
}
}
int maxOutputSize = (end - textFieldPos) + ((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}' -> HTML tags / strip
*
* 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->s.frametype = HB_FRAME_SUBTITLE;
out->s.start = in_start;
out->s.stop = in_stop;
out->sequence = in_sequence;
return out;
fail:
hb_log( "decssasub: malformed SSA subtitle packet: %.*s\n", in_size, in_data );
return NULL;
}
