Re: [FFmpeg-devel] [PATCH] Allow enabling SVC in libaomenc

[Chun-Min Chang <chun.m.chang@gmail.com>]

It looks like the command
```

git format-patch -s -o "outputfolder" --add-header "X-Unsent: 1"
--suffix .eml --to ffmpeg-devel@ffmpeg.org -1 1a2b3c4d

```
doesn't work for me. I'll see if I can find another way to submit the patch.

On Tue, Jun 11, 2024 at 1:22 PM Chun-Min Chang <chun.m.chang@gmail.com>
wrote:

> This patch updates libaomenc.c to accept parameters for SVC (Scalable
> Video Coding) settings via the FFmpeg API `av_opt_set`. The SVC
> configuration is applied based on the provided parameters. As libaom's
> SVC functionality only operates with constant bitrate encoding [1],
> these parameters will only take effect when the bitrate is set to
> constant.
>
> [1]
>
> https://aomedia.googlesource.com/aom/+/a7ef80c44bfb34b08254194b1ab72d4e93ff4b07/av1/encoder/svc_layercontext.h#115
>
> Signed-off-by: Chun-Min Chang <chun.m.chang@gmail.com>
> ---
>   libavcodec/libaomenc.c | 75 ++++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 75 insertions(+)
>
> diff --git a/libavcodec/libaomenc.c b/libavcodec/libaomenc.c
> index dec74ebecd..a8602a6b56 100644
> --- a/libavcodec/libaomenc.c
> +++ b/libavcodec/libaomenc.c
> @@ -30,6 +30,7 @@
>   #include <aom/aomcx.h>
>    #include "libavutil/avassert.h"
> +#include "libavutil/avstring.h"
>   #include "libavutil/base64.h"
>   #include "libavutil/common.h"
>   #include "libavutil/cpu.h"
> @@ -137,6 +138,7 @@ typedef struct AOMEncoderContext {
>       int enable_diff_wtd_comp;
>       int enable_dist_wtd_comp;
>       int enable_dual_filter;
> +    AVDictionary *svc_parameters;
>       AVDictionary *aom_params;
>   } AOMContext;
>   @@ -201,6 +203,7 @@ static const char *const ctlidstr[] = {
>       [AV1E_GET_TARGET_SEQ_LEVEL_IDX]     =
> "AV1E_GET_TARGET_SEQ_LEVEL_IDX",
>   #endif
>       [AV1_GET_NEW_FRAME_IMAGE]           = "AV1_GET_NEW_FRAME_IMAGE",
> +    [AV1E_SET_SVC_PARAMS]               = "AV1E_SET_SVC_PARAMS",
>   };
>    static av_cold void log_encoder_error(AVCodecContext *avctx, const
> char *desc)
> @@ -382,6 +385,31 @@ static av_cold int codecctl_imgp(AVCodecContext
> *avctx,
>       return 0;
>   }
>   +static av_cold int codecctl_svcp(AVCodecContext *avctx,
> +#ifdef UENUM1BYTE
> +                                 aome_enc_control_id id,
> +#else
> +                                 enum aome_enc_control_id id,
> +#endif
> +                                 aom_svc_params_t *svc_params)
> +{
> +    AOMContext *ctx = avctx->priv_data;
> +    char buf[80];
> +    int res;
> +
> +    snprintf(buf, sizeof(buf), "%s:", ctlidstr[id]);
> +
> +    res = aom_codec_control(&ctx->encoder, id, svc_params);
> +    if (res != AOM_CODEC_OK) {
> +        snprintf(buf, sizeof(buf), "Failed to get %s codec control",
> +                 ctlidstr[id]);
> +        log_encoder_error(avctx, buf);
> +        return AVERROR(EINVAL);
> +    }
> +
> +    return 0;
> +}
> +
>   static av_cold int aom_free(AVCodecContext *avctx)
>   {
>       AOMContext *ctx = avctx->priv_data;
> @@ -673,6 +701,18 @@ static int choose_tiling(AVCodecContext *avctx,
>       return 0;
>   }
>   +static void aom_svc_parse_int_array(int *dest, char *value, int
> max_entries)
> +{
> +    int dest_idx = 0;
> +    char *saveptr = NULL;
> +    char *token = av_strtok(value, ",", &saveptr);
> +
> +    while (token && dest_idx < max_entries) {
> +        dest[dest_idx++] = strtoul(token, NULL, 10);
> +        token = av_strtok(NULL, ",", &saveptr);
> +    }
> +}
> +
>   static av_cold int aom_init(AVCodecContext *avctx,
>                               const struct aom_codec_iface *iface)
>   {
> @@ -968,6 +1008,40 @@ static av_cold int aom_init(AVCodecContext *avctx,
>       if (ctx->enable_intrabc >= 0)
>           codecctl_int(avctx, AV1E_SET_ENABLE_INTRABC,
> ctx->enable_intrabc);
>   +    if (enccfg.rc_end_usage == AOM_CBR) {
> +        aom_svc_params_t svc_params = {};
> +        svc_params.framerate_factor[0] = 1;
> +        svc_params.number_spatial_layers = 1;
> +        svc_params.number_temporal_layers = 1;
> +
> +        const AVDictionaryEntry *en = NULL;
> +        while ((en = av_dict_iterate(ctx->svc_parameters, en))) {
> +            if (!strlen(en->value))
> +                return AVERROR(EINVAL);
> +
> +            if (!strcmp(en->key, "number_spatial_layers"))
> +                svc_params.number_spatial_layers = strtoul(en->value,
> NULL, 10);
> +            else if (!strcmp(en->key, "number_temporal_layers"))
> +                svc_params.number_temporal_layers = strtoul(en->value,
> NULL, 10);
> +            else if (!strcmp(en->key, "max_quantizers"))
> +                aom_svc_parse_int_array(svc_params.max_quantizers,
> en->value, AOM_MAX_LAYERS);
> +            else if (!strcmp(en->key, "min_quantizers"))
> +                aom_svc_parse_int_array(svc_params.min_quantizers,
> en->value, AOM_MAX_LAYERS);
> +            else if (!strcmp(en->key, "scaling_factor_num"))
> +                aom_svc_parse_int_array(svc_params.scaling_factor_num,
> en->value, AOM_MAX_SS_LAYERS);
> +            else if (!strcmp(en->key, "scaling_factor_den"))
> +                aom_svc_parse_int_array(svc_params.scaling_factor_den,
> en->value, AOM_MAX_SS_LAYERS);
> +            else if (!strcmp(en->key, "layer_target_bitrate"))
> +
> aom_svc_parse_int_array(svc_params.layer_target_bitrate, en->value,
> AOM_MAX_LAYERS);
> +            else if (!strcmp(en->key, "framerate_factor"))
> +                aom_svc_parse_int_array(svc_params.framerate_factor,
> en->value, AOM_MAX_TS_LAYERS);
> +        }
> +
> +        res = codecctl_svcp(avctx, AV1E_SET_SVC_PARAMS, &svc_params);
> +        if (res < 0)
> +            return res;
> +    }
> +
>   #if AOM_ENCODER_ABI_VERSION >= 23
>       {
>           const AVDictionaryEntry *en = NULL;
> @@ -1517,6 +1591,7 @@ static const AVOption options[] = {
>       { "enable-masked-comp",           "Enable masked compound",
>                      OFFSET(enable_masked_comp),
> AV_OPT_TYPE_BOOL, {.i64 = -1}, -1, 1, VE},
>       { "enable-interintra-comp",       "Enable interintra compound",
>                      OFFSET(enable_interintra_comp),
> AV_OPT_TYPE_BOOL, {.i64 = -1}, -1, 1, VE},
>       { "enable-smooth-interintra",     "Enable smooth interintra mode",
>                      OFFSET(enable_smooth_interintra),
> AV_OPT_TYPE_BOOL, {.i64 = -1}, -1, 1, VE},
> +    { "svc-parameters", "SVC configuration using a :-separated list of
> key=value parameters (only applied in CBR mode)",
> OFFSET(svc_parameters), AV_OPT_TYPE_DICT, { 0 }, 0, 0, VE},
>   #if AOM_ENCODER_ABI_VERSION >= 23
>       { "aom-params",                   "Set libaom options using a
> :-separated list of key=value pairs", OFFSET(aom_params),
> AV_OPT_TYPE_DICT, { 0 }, 0, 0, VE },
>   #endif
> --
> 2.34.1
>
>
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