[FFmpeg-devel] [PATCH v2] avfilter/showinfo: support Content Light Level information

[James Almer]

On 8/17/2019 8:09 PM, Limin Wang wrote:
> On Sat, Aug 17, 2019 at 02:49:29PM -0300, James Almer wrote:
>> On 8/17/2019 2:44 PM, James Almer wrote:
>>> On 8/10/2019 11:58 AM, lance.lmwang at gmail.com wrote:
>>>> From: Limin Wang <lance.lmwang at gmail.com>
>>>>
>>>> show real information instead of the unknown side data type message for HDR10 stream
>>>>
>>>> Signed-off-by: Limin Wang <lance.lmwang at gmail.com>
>>>> ---
>>>>  libavfilter/vf_showinfo.c | 17 +++++++++++++++++
>>>>  1 file changed, 17 insertions(+)
>>>>
>>>> diff --git a/libavfilter/vf_showinfo.c b/libavfilter/vf_showinfo.c
>>>> index 9fa322e..94d17bf 100644
>>>> --- a/libavfilter/vf_showinfo.c
>>>> +++ b/libavfilter/vf_showinfo.c
>>>> @@ -160,6 +160,20 @@ static void dump_mastering_display(AVFilterContext *ctx, AVFrameSideData *sd)
>>>>             av_q2d(mastering_display->min_luminance), av_q2d(mastering_display->max_luminance));
>>>>  }
>>>>  
>>>> +static void dump_content_light_metadata(AVFilterContext *ctx, AVFrameSideData *sd)
>>>> +{
>>>> +    AVContentLightMetadata* metadata = (AVContentLightMetadata*)sd->data;
>>>> +
>>>> +    if (sd->size < sizeof(*metadata)) {
>>>
>>> sizeof(AVContentLightMetadata) is not part of the ABI, so just remove
>>> this check.
>>
>> Oh, your first version was like that, and this one is the result of
>> someone suggesting to add the check.
>>
>> Pushed the correct version then.
> 
> thanks, when we should check the size as some other metadata have the
> size check?

When the doxy for the relevant struct or the side data type states its
size is part of the ABI.
Some are (AVReplayGain, display matrix, etc), and some aren't
(AVDynamicHDRPlus, AVContentLightMetadata, AVMasteringDisplayMetadata,
AVSphericalMapping, etc).
> 
>>
>>>
>>>> +        av_log(ctx, AV_LOG_ERROR, "invalid data");
>>>> +        return;
>>>> +    }
>>>> +
>>>> +    av_log(ctx, AV_LOG_INFO, "Content Light Level information: "
>>>> +           "MaxCLL=%d, MaxFALL=%d",
>>>> +           metadata->MaxCLL, metadata->MaxFALL);
>>>> +}
>>>> +
>>>>  static void dump_color_property(AVFilterContext *ctx, AVFrame *frame)
>>>>  {
>>>>      const char *color_range_str     = av_color_range_name(frame->color_range);
>>>> @@ -301,6 +315,9 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
>>>>          case AV_FRAME_DATA_MASTERING_DISPLAY_METADATA:
>>>>              dump_mastering_display(ctx, sd);
>>>>              break;
>>>> +        case AV_FRAME_DATA_CONTENT_LIGHT_LEVEL:
>>>> +            dump_content_light_metadata(ctx, sd);
>>>> +            break;
>>>>          default:
>>>>              av_log(ctx, AV_LOG_WARNING, "unknown side data type %d (%d bytes)",
>>>>                     sd->type, sd->size);
>>>>
>>>
>>
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