// Decoder functions
PyObject* _anim_decoder_new(PyObject* self, PyObject* args)
{
PyBytesObject *webp_string;
const uint8_t *webp;
Py_ssize_t size;
WebPData webp_src;
char* mode;
WebPDecoderConfig config;
WebPAnimDecoderObject* decp = NULL;
WebPAnimDecoder* dec = NULL;
if (!PyArg_ParseTuple(args, "S", &webp_string)) {
return NULL;
}
PyBytes_AsStringAndSize((PyObject *)webp_string, (char**)&webp, &size);
webp_src.bytes = webp;
webp_src.size = size;
// Sniff the mode, since the decoder API doesn't tell us
mode = "RGBA";
if (WebPGetFeatures(webp, size, &config.input) == VP8_STATUS_OK) {
if (!config.input.has_alpha) {
mode = "RGBX";
}
}
// Create the decoder (default mode is RGBA, if no options passed)
decp = PyObject_New(WebPAnimDecoderObject, &WebPAnimDecoder_Type);
if (decp) {
decp->mode = mode;
if (WebPDataCopy(&webp_src, &(decp->data))) {
dec = WebPAnimDecoderNew(&(decp->data), NULL);
if (dec) {
if (WebPAnimDecoderGetInfo(dec, &(decp->info))) {
decp->dec = dec;
return (PyObject*)decp;
}
}
}
PyObject_Del(decp);
}
PyErr_SetString(PyExc_RuntimeError, "could not create decoder object");
return NULL;
}
// Read animated WebP bitstream 'file_str' into 'AnimatedImage' struct.
static int ReadAnimatedWebP(const char filename[],
const WebPData* const webp_data,
AnimatedImage* const image, int dump_frames,
const char dump_folder[]) {
int ok = 0;
int dump_ok = 1;
uint32_t frame_index = 0;
int prev_frame_timestamp = 0;
WebPAnimDecoder* dec;
WebPAnimInfo anim_info;
memset(image, 0, sizeof(*image));
dec = WebPAnimDecoderNew(webp_data, NULL);
if (dec == NULL) {
fprintf(stderr, "Error parsing image: %s\n", filename);
goto End;
}
if (!WebPAnimDecoderGetInfo(dec, &anim_info)) {
fprintf(stderr, "Error getting global info about the animation\n");
goto End;
}
// Animation properties.
image->canvas_width = anim_info.canvas_width;
image->canvas_height = anim_info.canvas_height;
image->loop_count = anim_info.loop_count;
image->bgcolor = anim_info.bgcolor;
// Allocate frames.
if (!AllocateFrames(image, anim_info.frame_count)) return 0;
// Decode frames.
while (WebPAnimDecoderHasMoreFrames(dec)) {
DecodedFrame* curr_frame;
uint8_t* curr_rgba;
uint8_t* frame_rgba;
int timestamp;
if (!WebPAnimDecoderGetNext(dec, &frame_rgba, ×tamp)) {
fprintf(stderr, "Error decoding frame #%u\n", frame_index);
goto End;
}
assert(frame_index < anim_info.frame_count);
curr_frame = &image->frames[frame_index];
curr_rgba = curr_frame->rgba;
curr_frame->duration = timestamp - prev_frame_timestamp;
curr_frame->is_key_frame = 0; // Unused.
memcpy(curr_rgba, frame_rgba,
image->canvas_width * kNumChannels * image->canvas_height);
// Needed only because we may want to compare with GIF later.
CleanupTransparentPixels((uint32_t*)curr_rgba,
image->canvas_width, image->canvas_height);
if (dump_frames && dump_ok) {
dump_ok = DumpFrame(filename, dump_folder, frame_index, curr_rgba,
image->canvas_width, image->canvas_height);
if (!dump_ok) { // Print error once, but continue decode loop.
fprintf(stderr, "Error dumping frames to %s\n", dump_folder);
}
}
++frame_index;
prev_frame_timestamp = timestamp;
}
ok = dump_ok;
End:
WebPAnimDecoderDelete(dec);
return ok;
}
