Cykooz
commented
1 year ago As far as I understood from the libheif source code, the heif_context_set_max_decoding_threads function only applies to RGB images that consists of smaller images (tiles).
// If the maximum threads number is set to 0, the image tiles
// are decoded in the main thread. This is different from setting it to 1, which will
// generate a single background thread to decode the tiles.
// Note that this setting only affects libheif itself. The codecs itself may still use
// multi-threaded decoding. You can use it, for example, in cases where you are
// decoding several images in parallel anyway you thus want
// to minimize parallelism in each decoder.
LIBHEIF_API
void heif_context_set_max_decoding_threads(struct heif_context* ctx, int max_threads);heif_context_set_max_decoding_threads function set value of HeifContext::m_max_decoding_threads variable. But this variable is used only in one method:
// This function only works with RGB images.
Error HeifContext::decode_full_grid_image(heif_item_id ID,
std::shared_ptr<HeifPixelImage>& img,
const std::vector<uint8_t>& grid_data) constI can add set_max_decoding_threads() method into HeifContext but I'm not sure if that helps you.
chadaustin
First of all, I want to say thanks for this library. I'm writing a Rust program to compute rotation-independent perceptual hashes of the photos on my NAS, and libheif-rs has been very helpful.
When profiling on Windows with Superluminal, I noticed libheif is allocating threads per image. I'm already doing my own thread pools, so I'd prefer to have libheif not allocate threads.
I haven't gotten a chance to do a local fork and patch yet, but if you are interested in exposing
heif_context_set_max_decoding_threads, that would be useful!