[FFmpeg-devel] [PATCH] libavcodec/videotoolboxenc.c: add option to hevc encoder to prioritize speed.

[Andreas Rheinhardt]

Simone Karin Lehmann:
> 
> 
>> Am 14.04.2022 um 10:13 schrieb Thilo Borgmann <thilo.borgmann at mail.de>:
>>
>> Hi,
>>
>>>> diff --git a/libavcodec/videotoolboxenc.c b/libavcodec/videotoolboxenc.c
>>>> index 418ff00b8d..ab0dad6cbc 100644
>>>> --- a/libavcodec/videotoolboxenc.c
>>>> +++ b/libavcodec/videotoolboxenc.c
>>>> @@ -236,6 +236,7 @@ typedef struct VTEncContext {
>>>>     int allow_sw;
>>>>     int require_sw;
>>>>     double alpha_quality;
>>>> +    int64_t prio_speed;
>>
>> int64_t is definitely overkill.
> 
> I just wanted to make it consistent with hevc_options[] and other variables of AV_OPT_TYPE_BOOL. these are noted as .i64. 

AV_OPT_TYPE_BOOL expects an int target; the i64 is just the member used
for initialization (it is used because an int64_t can hold all the
values that make sense for a boolean -- it is therefore used for all
AV_OPT_TYPE_INT as well).
This also means that int64_t is not only overkill, but wrong (but it
happens to work on little-endian architectures).

> Anyway, I changed it to int.
> 
>>
>>>>
>>>>     bool flushing;
>>>>     int has_b_frames;
>>>> @@ -1145,6 +1146,17 @@ static int vtenc_create_encoder(AVCodecContext   *avctx,
>>>>         return AVERROR_EXTERNAL;
>>>>     }
>>>>
>>>> +    // prioritize speed over quality
>>>> +    if (vtctx->prio_speed) {
>>>> +        status = VTSessionSetProperty(vtctx->session,
>>>> +                                      kVTCompressionPropertyKey_PrioritizeEncodingSpeedOverQuality,
>>>> +                                      kCFBooleanTrue);
>>>> +        if (status) {
>>>> +            av_log(avctx, AV_LOG_ERROR, "Error setting PrioritizeEncodingSpeedOverQuality property: %d\n", status);
>>>> +            return AVERROR_EXTERNAL;
>>>> +        }
>>
>> If its called to priotize speed over qual, why not just print a warning and continue without this option?
> 
> You’re right. A warning seems much better. Changed this too.
> 
> Here’s the modified patch. 
> 
> Signed-off-by: Simone Karin Lehmann <simone at lisanet.de>
> ---
>  libavcodec/videotoolboxenc.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/libavcodec/videotoolboxenc.c b/libavcodec/videotoolboxenc.c
> index 270496b7a7..cf931569d1 100644
> --- a/libavcodec/videotoolboxenc.c
> +++ b/libavcodec/videotoolboxenc.c
> @@ -237,6 +237,7 @@ typedef struct VTEncContext {
>      int allow_sw;
>      int require_sw;
>      double alpha_quality;
> +    int prio_speed;
>  
>      bool flushing;
>      int has_b_frames;
> @@ -1146,6 +1147,16 @@ static int vtenc_create_encoder(AVCodecContext   *avctx,
>          return AVERROR_EXTERNAL;
>      }
>  
> +    // prioritize speed over quality
> +    if (vtctx->prio_speed) {
> +        status = VTSessionSetProperty(vtctx->session,
> +                                      kVTCompressionPropertyKey_PrioritizeEncodingSpeedOverQuality,
> +                                      kCFBooleanTrue);
> +        if (status) {
> +            av_log(avctx, AV_LOG_WARNING, "PrioritizeEncodingSpeedOverQuality property is not supported on this device. Ignoring.\n");
> +        }
> +    }
> +
>      if ((vtctx->codec_id == AV_CODEC_ID_H264 || vtctx->codec_id == AV_CODEC_ID_HEVC)
>              && max_rate > 0) {
>          bytes_per_second_value = max_rate >> 3;
> @@ -2745,6 +2756,7 @@ static const AVOption hevc_options[] = {
>      { "main10",   "Main10 Profile",   0, AV_OPT_TYPE_CONST, { .i64 = HEVC_PROF_MAIN10 }, INT_MIN, INT_MAX, VE, "profile" },
>  
>      { "alpha_quality", "Compression quality for the alpha channel", OFFSET(alpha_quality), AV_OPT_TYPE_DOUBLE, { .dbl = 0.0 }, 0.0, 1.0, VE },
> +    { "prio_speed", "prioritize encoding speed", OFFSET(prio_speed), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, VE },
>  
>      COMMON_OPTIONS
>      { NULL },