On Thu, Feb 15, 2024 at 12:13:59PM +0800, Zhao Zhili wrote: > > > > On Feb 14, 2024, at 06:50, Matthieu Bouron <matthieu.bou...@gmail.com> > > wrote: > > > > Hi, > > > > On Android, content providers are used for accessing files through shared > > mechanisms. One typical case would be an app willing to open a video from > > Google Photos, gallery apps, TikTok, Instagram or some other providers. > > A content URI looks something like "content://authority/path/id", see: > > https://developer.android.com/reference/android/content/ContentUris > > https://developer.android.com/guide/topics/providers/content-provider-basics > > > > It can currently be somehow managed through clumsy means such as using a > > "fd:" > > filename and crafting a special AVOption, which also has the drawback of > > requiring the third party to carry around opened file descriptors (with the > > multiple opened file limitations implied). Custom AVIOContexts are also an > > File descriptor is a general abstraction layer, it target more platforms than > Android specific content provider. Android provided getFd() API since API > level 12, I guess that’s the default method to deal with content provider in > native code. It’s a few lines of code to get native fd in Java, but dozens of > code > in C with JNI, which is what this patchset done. > > For multiple opened file limitations issue, they can close the file > descriptor after > open. It’s unlikely to reach the limit in normal case without leak. > > I’m OK to provide this android_content_protocol helper if user requests.
I've been doing this kind of work for 3/4 users (including myself) at this point and have to do it another time, this is what motivated me to propose this patchset. > > > option. Both options will have to deal with the JNI though and end users > > will > > have to re-implement the same exact thing. > > User still need to deal with JNI with the new android_content_protocol, more > or > less, it’s unavoidable. The advantage I see of using this protocol is that the user only need to call av_jni_set_jvm() + av_jni_set_android_app_ctx() at the start of the application and FFmpeg will handle the content-uri transparently. This is especially helpful if the Android application rely on multiple libraries that in turn rely on FFmpeg to read medias. > > > > > This patchset addresses this by adding a content provider protocol, which > > has > > an API fairly similar to fopen. Android 11 appears to provide something > > transparent within fopen(), but FFmpeg doesn't use it in the file protocol, > > and > > Android < 11 are still widely used. > > > > The first part move the JNI infrastructure from avcodec to avutil (it > > remains > > internally shared, there is little user implication), > > OK. JNI infrastructure should belong to avutil at the first place, so > hwcontext_mediacodec > and so on can use it. Unfortunately for those new avpriv_. What do you mean by "Unfortunately" ? Would you like to make the JNI API public ? [...] _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
