[FFmpeg-devel] [PATCH] videotoolbox: Add SDK ifdefs for use of kVTVideoDecoderReferenceMissingErr

[Martin Storsjö]

On Tue, 25 Mar 2025, Zhao Zhili wrote:

>
>
>> On Mar 25, 2025, at 18:46, Martin Storsjö <martin at martin.st> wrote:
>> 
>> On Tue, 25 Mar 2025, Zhao Zhili wrote:
>> 
>>> 
>>>> 在 2025年3月25日，下午6:01，Martin Storsjö <martin at martin.st> 写道：
>>>> This error constant was only added in the macOS 12 and iOS 15
>>>> SDKs.
>>>> If building with an older SDK, assume that the error doesn't
>>>> match this constant.
>>>> This fixes build errors with older SDKs after
>>>> c6214b0d691566c7cb0f2ff5be08a24c3534e5bb.
>>>> As this constant is declared unconditionally (without any target
>>>> version guards) in the headers, one can't reproduce this issue
>>>> while building with a newer SDK and targeting an older version
>>>> with -mmacosx-version-min=.
>>>> Technically, checking just one of MAC_OS_VERSION_12_0 and
>>>> __IPHONE_15_0 is enough; the macOS SDKs and iOS SDKs share these
>>>> files, so files from a similar point in time do have the same
>>>> defines. Therefore, we don't really need to expand this with
>>>> checks for tvOS, watchOS and other OS variants.
>>>> ---
>>>> libavcodec/videotoolbox.c | 5 +++++
>>>> 1 file changed, 5 insertions(+)
>>>> diff --git a/libavcodec/videotoolbox.c b/libavcodec/videotoolbox.c
>>>> index aaa6129576..7f7b910b26 100644
>>>> --- a/libavcodec/videotoolbox.c
>>>> +++ b/libavcodec/videotoolbox.c
>>>> @@ -728,8 +728,13 @@ static void videotoolbox_decoder_callback(void *opaque,
>>>>    }
>>>>
>>>>    if (!image_buffer) {
>>>> +#if defined(MAC_OS_VERSION_12_0) || defined(__IPHONE_15_0)
>>>> +        // kVTVideoDecoderReferenceMissingErr was defined in the macOS 12/iOS 15 SDK
>>>>        if (status != kVTVideoDecoderReferenceMissingErr)
>>>>            vtctx->reconfig_needed = true;
>>>> +#else
>>>> +        vtctx->reconfig_needed = true;
>>>> +#endif
>>> 
>>> I used its numeric value initially, but after checking the doc,
>>> 
>>> kVTVideoDecoderReferenceMissingErr
>>> iOS 6.0+
>>> iPadOS 6.0+
>>> Mac Catalyst 13.0+
>>> macOS 10.8+
>>> tvOS 10.2+
>>> visionOS 1.0+
>>> 
>>> I replaced it with the enum.
>>> 
>>> Now I wondering what does this macOS 10.8 mean.
>>> 
>>> Anyway, can we use the numeric value here?
>> 
>> Can you link to which docs declare this to be available since macOS 10.8?
>
> https://developer.apple.com/documentation/videotoolbox/kvtvideodecoderreferencemissingerr?language=objc

Thanks, that's interesting. Apparently they don't really track the 
availability of the individual enum entries very thoroughly here...

// Martin