diff options
| -rw-r--r-- | src/mot-encoder.cpp | 191 |
1 files changed, 135 insertions, 56 deletions
diff --git a/src/mot-encoder.cpp b/src/mot-encoder.cpp index 897333f..2de98c7 100644 --- a/src/mot-encoder.cpp +++ b/src/mot-encoder.cpp @@ -339,48 +339,26 @@ int main(int argc, char *argv[]) return 1; } -int encodeFile(int output_fd, std::string& fname, int fidx, int padlen) +// Resize the image or add a black border around it +// so that it is 320x240 pixels. +// Automatically reduce the quality to make sure the +// blobsize is not too large. +// +// Returns: the blobsize +size_t resizeImage(MagickWand* m_wand, unsigned char** blob) { - int ret = 0; - int fd=0, mothdrlen, nseg, lastseglen, i, last, curseglen; - unsigned char mothdr[32]; - MagickWand *m_wand = NULL; - PixelWand *p_wand = NULL; - size_t blobsize, height, width; - unsigned char *blob = NULL, *curseg = NULL; - MagickBooleanType err; - MSCDG msc; - unsigned char mscblob[8200]; - unsigned short int mscblobsize; - int quality = 100; - - m_wand = NewMagickWand(); - p_wand = NewPixelWand(); - PixelSetColor(p_wand, "black"); - - err = MagickReadImage(m_wand, fname.c_str()); - if (err == MagickFalse) { - fprintf(stderr, "Error - Unable to load image %s\n", fname.c_str()); - goto encodefile_out; - } - - height = MagickGetImageHeight(m_wand); - width = MagickGetImageWidth(m_wand); - //aspectRatio = (width * 1.0)/height; + size_t blobsize; + size_t height = MagickGetImageHeight(m_wand); + size_t width = MagickGetImageWidth(m_wand); - if (verbose) { - fprintf(stderr, "mot-encoder image: %s (id=%d). Original size: %zu x %zu. ", - fname.c_str(), fidx, width, height); - } + PixelWand *p_wand = NULL; while (height > 240 || width > 320) { if (height/240.0 > width/320.0) { - //width = height * aspectRatio; width = width * 240.0 / height; height = 240; } else { - //height = width * (1.0/aspectRatio); height = height * 320.0 / width; width = 320; } @@ -390,63 +368,164 @@ int encodeFile(int output_fd, std::string& fname, int fidx, int padlen) height = MagickGetImageHeight(m_wand); width = MagickGetImageWidth(m_wand); + // Make sure smaller images are 320x240 pixels, and + // add a black border + p_wand = NewPixelWand(); + PixelSetColor(p_wand, "black"); MagickBorderImage(m_wand, p_wand, (320-width)/2, (240-height)/2); + DestroyPixelWand(p_wand); MagickSetImageFormat(m_wand, "jpg"); + int quality = 100; + do { quality -= 5; MagickSetImageCompressionQuality(m_wand, quality); - blob = MagickGetImagesBlob(m_wand, &blobsize); + *blob = MagickGetImagesBlob(m_wand, &blobsize); } while (blobsize > MAXSLIDESIZE && quality > MINQUALITY); if (blobsize > MAXSLIDESIZE) { fprintf(stderr, "mot-encoder: Image Size too large after compression: %zu bytes\n", blobsize); - goto encodefile_out; + + return 0; } if (verbose) { fprintf(stderr, "mot-encoder resized image to %zu x %zu. Size after compression %zu bytes (q=%d)\n", width, height, blobsize, quality); } + return blobsize; +} - nseg = blobsize / MAXSEGLEN; - lastseglen = blobsize % MAXSEGLEN; - if (lastseglen != 0) { - nseg++; +int encodeFile(int output_fd, std::string& fname, int fidx, int padlen) +{ + int ret = 0; + int fd=0, mothdrlen, nseg, lastseglen, i, last, curseglen; + unsigned char mothdr[32]; + MagickWand *m_wand = NULL; + size_t blobsize, height, width; + unsigned char *blob = NULL; + unsigned char *curseg = NULL; + MagickBooleanType err; + MSCDG msc; + unsigned char mscblob[8200]; + unsigned short int mscblobsize; + + size_t orig_quality; + char* orig_format = NULL; + /* We handle JPEG differently, because we want to avoid recompressing the + * image if it is suitable as is + */ + bool orig_is_jpeg = false; + + /* By default, we do resize the image to 320x240, with a quality such that + * the blobsize is at most MAXSLIDESIZE. + * + * For JPEG input files that are already at the right resolution and at the + * right blobsize, we disable this to avoid quality loss due to recompression + */ + bool resize_required = true; + + m_wand = NewMagickWand(); + + err = MagickReadImage(m_wand, fname.c_str()); + if (err == MagickFalse) { + fprintf(stderr, "mot-encoder Error: Unable to load image %s\n", + fname.c_str()); + + goto encodefile_out; } - createMotHeader(blobsize, fidx, mothdr, &mothdrlen); - // Create the MSC Data Group C-Structure - createMscDG(&msc, 3, 0, 1, fidx, mothdr, mothdrlen); - // Generate the MSC DG frame (Figure 9 en 300 401) - packMscDG(mscblob, &msc, &mscblobsize); - writeMotPAD(output_fd, mscblob, mscblobsize, padlen); + height = MagickGetImageHeight(m_wand); + width = MagickGetImageWidth(m_wand); + orig_format = MagickGetImageFormat(m_wand); - for (i = 0; i < nseg; i++) { - curseg = blob + i * MAXSEGLEN; - if (i == nseg-1) { - curseglen = lastseglen; - last = 1; + // By default assume that the image has full quality and can be reduced + orig_quality = 100; + + if (orig_format) { + if (strcmp(orig_format, "JPEG") == 0) { + orig_quality = MagickGetImageCompressionQuality(m_wand); + orig_is_jpeg = true; + + if (verbose) { + fprintf(stderr, "mot-encoder image: %s (id=%d)." + " Original size: %zu x %zu. (%s, q=%zu)\n", + fname.c_str(), fidx, width, height, orig_format, orig_quality); + } } - else { - curseglen = MAXSEGLEN; - last = 0; + else if (verbose) { + fprintf(stderr, "mot-encoder image: %s (id=%d)." + " Original size: %zu x %zu. (%s)\n", + fname.c_str(), fidx, width, height, orig_format); } - createMscDG(&msc, 4, i, last, fidx, curseg, curseglen); + free(orig_format); + } + else { + fprintf(stderr, "mot-encoder Warning: Unable to detect image format %s\n", + fname.c_str()); + + fprintf(stderr, "mot-encoder image: %s (id=%d). Original size: %zu x %zu.\n", + fname.c_str(), fidx, width, height); + } + + if (orig_is_jpeg && height == 240 && width == 320) { + // Don't recompress the image and check if the blobsize is suitable + blob = MagickGetImagesBlob(m_wand, &blobsize); + + if (blobsize < MAXSLIDESIZE) { + fprintf(stderr, "mot-encoder image: %s (id=%d). No resize needed: %zu Bytes\n", + fname.c_str(), fidx, blobsize); + resize_required = false; + } + } + + if (resize_required) { + blobsize = resizeImage(m_wand, &blob); + } + + if (blobsize) { + nseg = blobsize / MAXSEGLEN; + lastseglen = blobsize % MAXSEGLEN; + if (lastseglen != 0) { + nseg++; + } + + createMotHeader(blobsize, fidx, mothdr, &mothdrlen); + // Create the MSC Data Group C-Structure + createMscDG(&msc, 3, 0, 1, fidx, mothdr, mothdrlen); + // Generate the MSC DG frame (Figure 9 en 300 401) packMscDG(mscblob, &msc, &mscblobsize); writeMotPAD(output_fd, mscblob, mscblobsize, padlen); - } - ret = 1; + for (i = 0; i < nseg; i++) { + curseg = blob + i * MAXSEGLEN; + if (i == nseg-1) { + curseglen = lastseglen; + last = 1; + } + else { + curseglen = MAXSEGLEN; + last = 0; + } + + createMscDG(&msc, 4, i, last, fidx, curseg, curseglen); + packMscDG(mscblob, &msc, &mscblobsize); + writeMotPAD(output_fd, mscblob, mscblobsize, padlen); + } + + ret = 1; + } encodefile_out: if (m_wand) { m_wand = DestroyMagickWand(m_wand); } + if (blob) { free(blob); } |