Merge "Minor fixes and small refactor in libavifinfo" into main
diff --git a/README.md b/README.md
index 83d9a6f..7d17d55 100644
--- a/README.md
+++ b/README.md
@@ -6,69 +6,44 @@
See `avifinfo.h` for details on the API and `avifinfo.c` for the implementation.
See `tests/avifinfo_demo.cc` for API usage examples.
-## Contents
-
-1. [How to use](#how-to-use)
-
- 1. [Build](#build)
- 2. [Test](#test)
-
-2. [Development](#development)
-
- 1. [Coding style](#coding-style)
- 2. [Submitting patches](#submitting-patches)
-
-3. [PHP implementation](#php-implementation)
-
-4. [Bug reports](#bug-reports)
-
-## How to use {#how-to-use}
+## How to use
**libavifinfo** can be used when only a few AVIF features are needed and when
linking to or including [libavif](https://github.com/AOMediaCodec/libavif) is
not an option. For decoding an image or extracting more features, please rely on
[libavif](https://github.com/AOMediaCodec/libavif).
-Note: `AvifInfoGetFeatures()` is designed to return the same `avifImage` field
-values as
+Note: The C implementation `AvifInfoGetFeatures()` is designed to return the
+same `avifImage` field values as
[`avifDecoderParse()`](https://github.com/AOMediaCodec/libavif/blob/e34204f5370509c72b3b2f065e5ebb2767cbbd48/include/avif/avif.h#L1049).
-However **libavifinfo** is more permissive and may return features of images
-considered invalid by **libavif**.
+However **libavifinfo** is often more permissive and may return features of
+images considered invalid by **libavif**.
-### Build {#build}
+## C implementation
-`avifinfo.c` is written in C. To build from this directory:
-
-```sh
-mkdir build && \
-cd build && \
-cmake .. && \
-cmake --build . --config Release
-```
-
-### Test {#test}
-
-Tests are written in C++. GoogleTest is required.
-
-```sh
-mkdir build && \
-cd build && \
-cmake .. -DAVIFINFO_BUILD_TESTS=ON && \
-cmake --build . --config Debug && \
-ctest .
-```
-
-## Development {#development}
-
-### Coding style {#coding-style}
+### Coding style
[Google C/C++ Style Guide](https://google.github.io/styleguide/cppguide.html) is
used in this project.
-### Submitting patches {#submitting-patches}
+### Build
-If you would like to contribute to **libavifinfo**, please follow the steps for
-**libaom** at https://aomedia.googlesource.com/aom/#submitting-patches.
+`avifinfo.c` is written in C. To build from this directory:
+
+```sh
+cmake -S . -B build && \
+cmake --build build --config Release
+```
+
+### Test
+
+GoogleTest is required for the C++ tests (e.g. `sudo apt install libgtest-dev`).
+
+```sh
+cmake -S . -B build -DAVIFINFO_BUILD_TESTS=ON && \
+cmake --build build --config Debug && \
+ctest --test-dir build build
+```
## PHP implementation
@@ -81,7 +56,40 @@
See `avifinfo_test.php` for a usage example.
-## Bug reports {#bug-reports}
+### PHP test
+
+```sh
+cd tests && \
+php avifinfo_test.php
+```
+
+## Development
+
+### Submitting patches {#submitting-patches}
+
+If you would like to contribute to **libavifinfo**, please follow the steps for
+**libaom** at https://aomedia.googlesource.com/aom/#submitting-patches. Summary:
+
+- Log in at https://aomedia.googlesource.com
+- Sign in at https://aomedia-review.googlesource.com
+- Execute the contributor agreement if necessary, see http://aomedia.org/license
+- Test all implementations as described in this document
+- Copy the commit message hook:
+ `cd libavifinfo && curl -Lo .git/hooks/commit-msg https://chromium-review.googlesource.com/tools/hooks/commit-msg && chmod u+x .git/hooks/commit-msg`
+- Create a commit
+- `git push https://aomedia.googlesource.com/libavifinfo/ HEAD:refs/for/main`
+- Request a review from a project maintainer
+
+## Known users of libavifinfo
+
+- [Chromium](https://source.chromium.org/chromium/chromium/src/+/main:third_party/libavifinfo)
+ uses the C impl to extract the gain map item for HDR tone mapping.
+- [PHP-src](https://github.com/php/php-src/tree/master/ext/standard/libavifinfo)
+ uses the C impl to parse image features without relying on libavif or libheif.
+- [WordPress](https://github.com/WordPress/wordpress-develop/blob/trunk/src/wp-includes/class-avif-info.php)
+ uses the PHP impl to support AVIF images with older versions of PHP.
+
+## Bug reports
Bug reports can be filed in the Alliance for Open Media
[issue tracker](https://bugs.chromium.org/p/aomedia/issues/list).
diff --git a/avifinfo.c b/avifinfo.c
index 62abf28..599c019 100644
--- a/avifinfo.c
+++ b/avifinfo.c
@@ -318,11 +318,18 @@
// Read the 32 least-significant bits.
box->size = AvifInfoInternalReadBigEndian(data + 4, sizeof(uint32_t));
} else if (box->size == 0) {
+ // ISO/IEC 14496-12 4.2.2:
+ // if size is 0, then this box shall be in a top-level box
+ // (i.e. not contained in another box)
+ AVIFINFO_CHECK(nesting_level == 0, kInvalid);
box->size = num_remaining_bytes;
}
AVIFINFO_CHECK(box->size >= box_header_size, kInvalid);
AVIFINFO_CHECK(box->size <= num_remaining_bytes, kInvalid);
+ // 16 bytes of usertype should be read here if the box type is 'uuid'.
+ // 'uuid' boxes are skipped so usertype is part of the skipped body.
+
const int has_fullbox_header =
!memcmp(box->type, "meta", 4) || !memcmp(box->type, "pitm", 4) ||
!memcmp(box->type, "ipma", 4) || !memcmp(box->type, "ispe", 4) ||
@@ -483,7 +490,11 @@
if (strcmp(aux_type, kGainmapStr) == 0) {
// Note: It is unlikely but it is possible that this gain map
// does not belong to the primary item or a tile. Ignore this issue.
- features->gainmap_property_index = box_index;
+ if (box_index <= AVIFINFO_MAX_VALUE) {
+ features->gainmap_property_index = (uint8_t)box_index;
+ } else {
+ features->data_was_skipped = 1;
+ }
} else if (box.content_size >= kAlphaStrLength &&
memcmp(aux_type, kAlphaStr, kGainmapStrLength) == 0) {
// The beginning of the aux type matches the alpha aux type string.
@@ -511,7 +522,7 @@
AVIFINFO_RETURN(kNotFound);
}
-// Parses a 'stream' of an "iprp" box into 'features'. The "ipco" box contain
+// Parses a 'stream' of an "iprp" box into 'features'. The "ipco" box contains
// the properties which are linked to items by the "ipma" box.
static AvifInfoInternalStatus ParseIprp(int nesting_level,
AvifInfoInternalStream* stream,
@@ -692,38 +703,37 @@
if (!memcmp(box.type, "infe", 4)) {
// See ISO/IEC 14496-12:2015(E) 8.11.6.2
- uint32_t num_read_bytes = 0;
-
const uint32_t num_bytes_per_id = (box.version == 2) ? 2 : 4;
const uint8_t* data;
// item_ID (16 or 32) + item_protection_index (16) + item_type (32).
- AVIFINFO_CHECK((num_bytes_per_id + 6) <= num_remaining_bytes, kInvalid);
+ AVIFINFO_CHECK(num_bytes_per_id + 2 + 4 <= box.content_size, kInvalid);
AVIFINFO_CHECK_FOUND(
AvifInfoInternalRead(stream, num_bytes_per_id, &data));
- num_read_bytes += num_bytes_per_id;
const uint32_t item_id =
AvifInfoInternalReadBigEndian(data, num_bytes_per_id);
- // Skip item_protection_index
+ // Skip item_protection_index.
AVIFINFO_CHECK_FOUND(AvifInfoInternalSkip(stream, 2));
- num_read_bytes += 2;
const uint8_t* item_type;
AVIFINFO_CHECK_FOUND(AvifInfoInternalRead(stream, 4, &item_type));
- num_read_bytes += 4;
if (!memcmp(item_type, "tmap", 4)) {
// Tone Mapped Image: indicates the presence of a gain map.
- features->tone_mapped_item_id = item_id;
+ if (item_id <= AVIFINFO_MAX_VALUE) {
+ features->tone_mapped_item_id = (uint8_t)item_id;
+ } else {
+ features->data_was_skipped = 1;
+ }
}
- AVIFINFO_CHECK_FOUND(
- AvifInfoInternalSkip(stream, box.content_size - num_read_bytes));
+ AVIFINFO_CHECK_FOUND(AvifInfoInternalSkip(
+ stream, box.content_size - (num_bytes_per_id + 2 + 4)));
} else {
AVIFINFO_CHECK_FOUND(AvifInfoInternalSkip(stream, box.content_size));
}
num_remaining_bytes -= box.size;
- if (num_remaining_bytes <= 0) break;
+ if (num_remaining_bytes == 0) break; // Ignore entry_count bigger than box.
}
AVIFINFO_RETURN(kNotFound);
}
@@ -822,7 +832,6 @@
AVIFINFO_CHECK_FOUND(AvifInfoInternalSkip(stream, box.content_size));
}
}
- AVIFINFO_RETURN(kInvalid); // No "meta" no good.
}
//------------------------------------------------------------------------------
diff --git a/avifinfo.php b/avifinfo.php
index bebcc35..81269ec 100644
--- a/avifinfo.php
+++ b/avifinfo.php
@@ -250,6 +250,10 @@
// Read the 32 least-significant bits.
$this->size = read_big_endian( substr( $data, 4, 4 ), 4 );
} else if ( $this->size == 0 ) {
+ // ISO/IEC 14496-12 4.2.2:
+ // if size is 0, then this box shall be in a top-level box
+ // (i.e. not contained in another box)
+ // Unfortunately the presence of a parent box is unknown here.
$this->size = $num_remaining_bytes;
}
if ( $this->size < $header_size ) {
@@ -259,6 +263,9 @@
return INVALID;
}
+ // 16 bytes of usertype should be read here if the box type is 'uuid'.
+ // 'uuid' boxes are skipped so usertype is part of the skipped body.
+
$has_fullbox_header = $this->type == 'meta' || $this->type == 'pitm' ||
$this->type == 'ipma' || $this->type == 'ispe' ||
$this->type == 'pixi' || $this->type == 'iref' ||
@@ -477,7 +484,7 @@
/**
* Parses an "iprp" box.
*
- * The "ipco" box contain the properties which are linked to items by the "ipma" box.
+ * The "ipco" box contains the properties which are linked to items by the "ipma" box.
*
* @param stream $handle The resource the box will be parsed from.
* @param int $num_remaining_bytes The number of bytes that should be available from the resource.
