[FFmpeg-devel] [PATCH] add media100 bsf and use it

[Andreas Rheinhardt]

Paul B Mahol:
> -static int media100_decode_frame(AVCodecContext *avctx,
> -                                 AVFrame *frame, int *got_frame,
> -                                 AVPacket *avpkt)
> +static int filter(AVBSFContext *ctx, AVPacket *avpkt)
>  {
> -    Media100Context *ctx = avctx->priv_data;
> +    Media100Context *s = ctx->priv_data;
>      unsigned second_field_offset = 0;
>      unsigned next_field = 0;
>      unsigned dht_offset[2];
> @@ -83,18 +62,20 @@ static int media100_decode_frame(AVCodecContext *avctx,
>      AVPacket *pkt;
>      int ret;
>  
> -    if (avpkt->size + 1024 > ctx->pkt->size) {
> -        ret = av_grow_packet(ctx->pkt, avpkt->size + 1024 - ctx->pkt->size);
> -        if (ret < 0)
> -            return ret;
> -    }
> +    ret = ff_bsf_get_packet_ref(ctx, avpkt);

The avpkt here is destined for output; you should use s->pkt to get the
new input packet. This will allow to avoid the av_packet_move_ref() below.

> +    if (ret < 0)
> +        return ret;
>  
> -    ret = av_packet_make_writable(ctx->pkt);
> +    ret = av_new_packet(s->pkt, avpkt->size + 1024);
> +    if (ret < 0)
> +        return ret;
> +
> +    ret = av_packet_make_writable(s->pkt);

av_new_packet() always returns writable packets.

>      if (ret < 0)
>          return ret;
>  
>      bytestream2_init(&gb, avpkt->data, avpkt->size);
> -    bytestream2_init_writer(&pb, ctx->pkt->data, ctx->pkt->size);
> +    bytestream2_init_writer(&pb, s->pkt->data, s->pkt->size);
>  
>  second_field:
>      bytestream2_put_be32(&pb, 0);
> @@ -107,8 +88,8 @@ second_field:
>      sof_offset[field] = bytestream2_tell_p(&pb);
>      bytestream2_put_be16(&pb, 17);
>      bytestream2_put_byte(&pb, 8);
> -    bytestream2_put_be16(&pb, avctx->height / 2);
> -    bytestream2_put_be16(&pb, avctx->width);
> +    bytestream2_put_be16(&pb, ctx->par_in->height / 2);
> +    bytestream2_put_be16(&pb, ctx->par_in->width);
>      bytestream2_put_byte(&pb, 3);
>      bytestream2_put_byte(&pb, 1);
>      bytestream2_put_byte(&pb, 0x21);
> @@ -164,7 +145,7 @@ second_field:
>          goto second_field;
>      }
>  
> -    pkt = ctx->pkt;
> +    pkt = s->pkt;
>  
>      AV_WB32(pkt->data +  8, second_field_offset);
>      AV_WB32(pkt->data + 12, second_field_offset);
> @@ -186,40 +167,33 @@ second_field:
>  
>      pkt->size = bytestream2_tell_p(&pb);
>  
> -    ret = avcodec_send_packet(ctx->avctx, pkt);
> -    if (ret < 0) {
> -        av_log(avctx, AV_LOG_ERROR, "Error submitting a packet for decoding\n");
> -        return ret;
> -    }
> +    av_packet_copy_props(pkt, avpkt);
> +    av_packet_unref(avpkt);
> +    av_packet_move_ref(avpkt, s->pkt);
>  
> -    ret = avcodec_receive_frame(ctx->avctx, frame);
> -    if (ret < 0)
> -        return ret;
> +    return 0;
> +}
>