[FFmpeg-devel] [PATCH v4 1/2] avcodec/libvpxenc: add VP9 temporal scalability encoding option

[James Zern]

Hi,

On Fri, Jan 10, 2020 at 9:59 AM Wonkap Jang
<wonkap-at-google.com at ffmpeg.org> wrote:
>
> This commit reuses the configuration options for VP8 that enables
> temporal scalability for VP9. It also adds a way to enable three
> preset temporal structures (refer to the documentation for more
> detail) that can be used in offline encoding.
> ---
>  doc/encoders.texi      |  18 ++-
>  libavcodec/libvpxenc.c | 251 +++++++++++++++++++++++++++++++++++++----
>  2 files changed, 243 insertions(+), 26 deletions(-)
>
> [...]
>  #endif
> @@ -223,8 +231,16 @@ static av_cold void dump_enc_cfg(AVCodecContext *avctx,
>             "  %*s%u\n", width, "ts_number_layers:", cfg->ts_number_layers);
>      av_log(avctx, level,
>             "\n  %*s", width, "ts_target_bitrate:");

This should move to the vp8 branch and a new heading added for vp9's
layer_target_bitrate.

> [...]
> -static int vp8_ts_param_parse(struct vpx_codec_enc_cfg *enccfg, char *key, char *value)
> +static void set_temporal_layer_pattern(int layering_mode,
> +                                       vpx_codec_enc_cfg_t *cfg,
> +                                       int *layer_flags,
> +                                       int *flag_periodicity)
> +{
> +    switch (layering_mode) {
> +    case 2: {
> +        /**
> +         * 2-layers, 2-frame period.
> +         */
> +        int ids[2] = { 0, 1 };

these can be static const.

> +        cfg->ts_periodicity = 2;
> +        *flag_periodicity = 2;
> +        cfg->ts_number_layers = 2;
> +        cfg->ts_rate_decimator[0] = 2;
> +        cfg->ts_rate_decimator[1] = 1;
> +        memcpy(cfg->ts_layer_id, ids, sizeof(ids));
> +
> +        layer_flags[0] =
> +             VP8_EFLAG_NO_REF_GF | VP8_EFLAG_NO_REF_ARF |
> +             VP8_EFLAG_NO_UPD_GF | VP8_EFLAG_NO_UPD_ARF;
> +

this line can be removed.

> +        layer_flags[1] =
> +            VP8_EFLAG_NO_UPD_ARF | VP8_EFLAG_NO_UPD_GF |
> +            VP8_EFLAG_NO_UPD_LAST |
> +            VP8_EFLAG_NO_REF_ARF | VP8_EFLAG_NO_REF_GF;
> +        break;
> +    }
> +    case 3: {
> +        /**
> +         * 3-layers structure with one reference frame.
> +         *  This works same as temporal_layering_mode 3.
> +         *
> +         * 3-layers, 4-frame period.
> +         */
> +        int ids[4] = { 0, 2, 1, 2 };
> +        cfg->ts_periodicity = 4;
> +        *flag_periodicity = 4;
> +        cfg->ts_number_layers = 3;
> +        cfg->ts_rate_decimator[0] = 4;
> +        cfg->ts_rate_decimator[1] = 2;
> +        cfg->ts_rate_decimator[2] = 1;
> +        memcpy(cfg->ts_layer_id, ids, sizeof(ids));
> +
> +        /**
> +         * 0=L, 1=GF, 2=ARF,

what about [3]?

> +         * Intra-layer prediction disabled.
> +         */
> +        layer_flags[0] =
> +            VP8_EFLAG_NO_REF_GF | VP8_EFLAG_NO_REF_ARF |
> +            VP8_EFLAG_NO_UPD_GF | VP8_EFLAG_NO_UPD_ARF;
> +        layer_flags[2] =

can you reorder this to be in the natural 0...3 order?

> [...]
> +        /**
> +         * 0=L, 1=GF, 2=ARF, Intra-layer prediction disabled.
> +         */
> +        layer_flags[0] =
> +            VP8_EFLAG_NO_REF_GF | VP8_EFLAG_NO_REF_ARF |
> +            VP8_EFLAG_NO_UPD_GF | VP8_EFLAG_NO_UPD_ARF;
> +        layer_flags[2] =

same comment here about order.

> [...]
> +
> +#if (VPX_ENCODER_ABI_VERSION >= 12) && CONFIG_LIBVPX_VP9_ENCODER
> +    enccfg->temporal_layering_mode = 1; // only bypass mode is being supported for now.

...mode is supported...

> +    enccfg->ss_number_layers = 1; // making sure the spatial scalability is off. Will support this in future.

this can be TODO: add spatial scalability support.

> +#endif
> +    if (ts_layering_mode) {
> +      // make sure the ts_layering_mode comes at the end of the ts_parameter string to ensure that
> +      // correct configuration is done.
> +      ctx->ts_layer_flags = av_malloc(sizeof(int) * VPX_TS_MAX_PERIODICITY);

prefer sizeof(var).

> [...]
>
> -    if(!avctx->bit_rate)
> -        if(avctx->rc_max_rate || avctx->rc_buffer_size || avctx->rc_initial_buffer_occupancy) {
> +    if (!avctx->bit_rate)
> +        if (avctx->rc_max_rate || avctx->rc_buffer_size || avctx->rc_initial_buffer_occupancy) {

this is unrelated to the change, please remove it.

> [...]
> +#if VPX_ENCODER_ABI_VERSION >= 12
> +        codecctl_int(avctx, VP9E_SET_SVC, 1);
> +        codecctl_intp(avctx, VP9E_SET_SVC_PARAMETERS, (int *) &svc_params);

drop the space after the cast.

> [...]
> +#if CONFIG_LIBVPX_VP9_ENCODER && VPX_ENCODER_ABI_VERSION >= 12
> +        else if (avctx->codec_id == AV_CODEC_ID_VP9) {
> +            codecctl_intp(avctx, VP9E_SET_SVC_LAYER_ID, (int *) &layer_id);

drop the space after the cast.