[FFmpeg-devel] [PATCH]Allow MPEG4 VDPAU decoding

[Michael Niedermayer]

On Thu, Nov 05, 2009 at 02:19:30AM +0100, Carl Eugen Hoyos wrote:
> Hi!
>
> Attached is a new (tested) version of the patch to support MPEG4 VDPAU 
> decoding.
>
> Please comment, Carl Eugen
[...]
> +void ff_vdpau_mpeg4_decode_picture(MpegEncContext *s, const uint8_t *buf,
> +                                   int buf_size)
> +{
> +    struct vdpau_render_state *render, *last, *next;
> +    int i;
> +
> +    if (!s->current_picture_ptr) return;
> +
> +    render = (struct vdpau_render_state *)s->current_picture_ptr->data[0];
> +    assert(render);
> +
> +    /* fill VdpPictureInfoMPEG4Part2 struct */
> +    render->info.mpeg4.vop_time_increment_resolution     = s->avctx->time_base.den;
> +    render->info.mpeg4.vop_coding_type                   = 0;
> +    render->info.mpeg4.vop_fcode_forward                 = s->f_code;
> +    render->info.mpeg4.vop_fcode_backward                = s->b_code;
> +    render->info.mpeg4.resync_marker_disable             = !s->resync_marker;
> +    render->info.mpeg4.interlaced                        = !s->progressive_sequence;
> +    render->info.mpeg4.quant_type                        = s->mpeg_quant;
> +    render->info.mpeg4.quarter_sample                    = s->quarter_sample;
> +    render->info.mpeg4.short_video_header                = s->avctx->codec->id == CODEC_ID_H263;
> +    render->info.mpeg4.rounding_control                  = s->no_rounding;
> +    render->info.mpeg4.alternate_vertical_scan_flag      = s->alternate_scan;
> +    render->info.mpeg4.top_field_first                   = s->top_field_first;
> +    for (i = 0; i < 64; ++i) {
> +        render->info.mpeg4.intra_quantizer_matrix[i]     = s->intra_matrix[i];
> +        render->info.mpeg4.non_intra_quantizer_matrix[i] = s->inter_matrix[i];
> +    }
> +    render->info.mpeg4.forward_reference                 = VDP_INVALID_HANDLE;
> +    render->info.mpeg4.backward_reference                = VDP_INVALID_HANDLE;
> +
> +    switch (s->pict_type) {
> +    case FF_B_TYPE:
> +        next = (struct vdpau_render_state *)s->next_picture.data[0];
> +        assert(next);
> +        render->info.mpeg4.backward_reference     = next->surface;
> +        render->info.mpeg4.vop_coding_type        = 2;
> +        // no break here, going to set forward prediction
> +    case FF_P_TYPE:
> +        last = (struct vdpau_render_state *)s->last_picture.data[0];

> +        if (!last) // FIXME: Does this test make sense?
> +            last = render; // predict second field from the first

i dont think this test makes sense, there is no I field + P field in
mpeg4-asp actually there are no field pictures in there at all ...


> +        render->info.mpeg4.forward_reference      = last->surface;

> +        if (!render->info.mpeg4.vop_coding_type)
> +            render->info.mpeg4.vop_coding_type    = 1;

this looks unneeded as well


[...]
> @@ -67,6 +67,8 @@
>          s->h263_pred = 1;
>          s->low_delay = 0; //default, might be overriden in the vol header during header parsing
>          avctx->chroma_sample_location = AVCHROMA_LOC_LEFT;
> +        if (CONFIG_MPEG4_VDPAU_DECODER && (s->avctx->codec->capabilities & CODEC_CAP_HWACCEL_VDPAU))
> +            avctx->codec->pix_fmts = (enum PixelFormat[]){PIX_FMT_VDPAU_MPEG4, PIX_FMT_NONE};
>          break;
>      case CODEC_ID_MSMPEG4V1:
>          s->h263_msmpeg4 = 1;

you cant do that, avctx->codec is shared amongth all instances of mpeg4
decoders


[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Asymptotically faster algorithms should always be preferred if you have
asymptotical amounts of data
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