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[FIX] DVB OCR: Memory Leak & Quantization Issues #1675

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Merged
cfsmp3 merged 2 commits into from
Mar 22, 2025
Merged

[FIX] DVB OCR: Memory Leak & Quantization Issues #1675

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580a168
fix: do not free ocr text before return
hrideshmg Mar 14, 2025
435de6c
fix(OCR): erode and dilate function
hrideshmg Mar 14, 2025
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51 changes: 24 additions & 27 deletions src/lib_ccx/ocr.c
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Original file line number Diff line number Diff line change
Expand Up @@ -9,7 +9,6 @@
#include "ccx_encoders_helpers.h"
#include "ccx_encoders_spupng.h"
#include "ocr.h"
#undef OCR_DEBUG

struct ocrCtx
{
Expand Down Expand Up @@ -686,7 +685,6 @@ char *ocr_bitmap(void *arg, png_color *palette, png_byte *alpha, unsigned char *
TessResultIteratorDelete(ri);
}
// End Color Detection
freep(&text_out);
boxDestroy(&crop_points);

pixDestroy(&pix);
Expand All @@ -698,47 +696,31 @@ char *ocr_bitmap(void *arg, png_color *palette, png_byte *alpha, unsigned char *
return text_out;
}

void erode(png_color *palette, png_byte *alpha, uint8_t *bitmap, int w, int h, int nb_color)
void erode(png_color *palette, png_byte *alpha, uint8_t *bitmap, int w, int h, int nb_color, int background_index)
{
int background_index;
for (background_index = 0; background_index < nb_color; background_index++)
{
if (alpha[background_index])
{
break;
}
}
// we will use a 2*2 kernel for the erosion
for (int row = 0; row < h - 1; row++)
{
for (int col = 0; col < w - 1; col++)
{
if (alpha[bitmap[row * w + col]] || alpha[bitmap[(row + 1) * w + col]] ||
alpha[bitmap[row * w + (col + 1)]] || alpha[bitmap[(row + 1) * w + (col + 1)]])
if (bitmap[row * w + col] == background_index || bitmap[(row + 1) * w + col] == background_index ||
bitmap[row * w + (col + 1)] == background_index || bitmap[(row + 1) * w + (col + 1)] == background_index)
{
bitmap[row * w + col] = background_index;
}
}
}
}

void dilate(png_color *palette, png_byte *alpha, uint8_t *bitmap, int w, int h, int nb_color)
void dilate(png_color *palette, png_byte *alpha, uint8_t *bitmap, int w, int h, int nb_color, int foreground_index)
{
int foreground_index;
for (foreground_index = 0; foreground_index < nb_color; foreground_index++)
{
if (!alpha[foreground_index])
{
break;
}
}
// we will use a 2*2 kernel for the erosion
for (int row = 0; row < h - 1; row++)
{
for (int col = 0; col < w - 1; col++)
{
if (!(alpha[bitmap[row * w + col]] && alpha[bitmap[(row + 1) * w + col]] &&
alpha[bitmap[row * w + (col + 1)]] && alpha[bitmap[(row + 1) * w + (col + 1)]]))
if ((bitmap[row * w + col] == foreground_index && bitmap[(row + 1) * w + col] == foreground_index &&
bitmap[row * w + (col + 1)] == foreground_index && bitmap[(row + 1) * w + (col + 1)] == foreground_index))
{
bitmap[row * w + col] = foreground_index;
}
Expand Down Expand Up @@ -769,6 +751,7 @@ static int quantize_map(png_byte *alpha, png_color *palette,
*/
uint32_t *mcit = NULL;
struct transIntensity ti = {alpha, palette};
int text_color, text_bg_color;

int ret = 0;

Expand Down Expand Up @@ -835,6 +818,14 @@ static int quantize_map(png_byte *alpha, png_color *palette,
max_ind = j;
}
}

// Assume second most frequent color to be text background (first is alpha channel)
if (i == 1)
text_bg_color = iot[max_ind];
// Assume third most frequent color to be text color
if (i == 2)
text_color = iot[max_ind];

for (j = i; j > 0 && max_ind < mcit[j - 1]; j--)
{
mcit[j] = mcit[j - 1];
Expand Down Expand Up @@ -878,8 +869,8 @@ static int quantize_map(png_byte *alpha, png_color *palette,
palette[iot[i]].green = palette[index].green;
}
}
erode(palette, alpha, bitmap, w, h, nb_color);
dilate(palette, alpha, bitmap, w, h, nb_color);
erode(palette, alpha, bitmap, w, h, nb_color, text_bg_color);
dilate(palette, alpha, bitmap, w, h, nb_color, text_color);
#ifdef OCR_DEBUG
ccx_common_logging.log_ftn("Colors present in quantized Image\n");
for (int i = 0; i < nb_color; i++)
Expand Down Expand Up @@ -1062,7 +1053,13 @@ char *paraof_ocrtext(struct cc_subtitle *sub, struct encoder_ctx *context)
len += strlen(rect->ocr_text);
}
if (len <= 0)
{
for (i = 0, rect = sub->data; i < sub->nb_data; i++, rect++)
{
freep(&rect->ocr_text);
}
return NULL;
}
else
{
str = malloc(len + 1 + 10); // Extra space for possible trailing '/n's at the end of tesseract UTF8 text
Expand All @@ -1076,7 +1073,7 @@ char *paraof_ocrtext(struct cc_subtitle *sub, struct encoder_ctx *context)
if (!rect->ocr_text)
continue;
add_ocrtext2str(str, rect->ocr_text, context->encoded_crlf, context->encoded_crlf_length);
free(rect->ocr_text);
freep(&rect->ocr_text);
}
return str;
}
Expand Down
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