[FFmpeg-devel] [PATCH 2/2] vp8: WebP decoding support

Pascal Massimino pascal.massimino at gmail.com
Fri Mar 22 13:47:22 CET 2013


Hi Michael,

On Fri, Mar 22, 2013 at 4:16 AM, Michael Niedermayer <michaelni at gmx.at>wrote:

> VP8L, padding and bounds checks by Pascal Massimino
>
> Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
>


LGTM. Tested both patches locally on a set of random-featured .webp files
and results were OK.


> ---
>  libavcodec/Makefile     |    1 +
>  libavcodec/allcodecs.c  |    1 +
>  libavcodec/avcodec.h    |    1 +
>  libavcodec/codec_desc.c |    7 ++++++
>  libavcodec/vp8.c        |   61
> +++++++++++++++++++++++++++++++++++++++++++++++
>  5 files changed, 71 insertions(+)
>
> diff --git a/libavcodec/Makefile b/libavcodec/Makefile
> index 0d73067..bbb7083 100644
> --- a/libavcodec/Makefile
> +++ b/libavcodec/Makefile
> @@ -461,6 +461,7 @@ OBJS-$(CONFIG_VP8_DECODER)             += vp8.o
> vp8dsp.o vp56rac.o
>  OBJS-$(CONFIG_VPLAYER_DECODER)         += textdec.o ass.o
>  OBJS-$(CONFIG_VQA_DECODER)             += vqavideo.o
>  OBJS-$(CONFIG_WAVPACK_DECODER)         += wavpack.o
> +OBJS-$(CONFIG_WEBP_DECODER)            += vp8.o vp8dsp.o vp56rac.o
>  OBJS-$(CONFIG_WEBVTT_DECODER)          += webvttdec.o
>  OBJS-$(CONFIG_WMALOSSLESS_DECODER)     += wmalosslessdec.o wma_common.o
>  OBJS-$(CONFIG_WMAPRO_DECODER)          += wmaprodec.o wma.o wma_common.o
> diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
> index 1eaf2d3..4ff63ef 100644
> --- a/libavcodec/allcodecs.c
> +++ b/libavcodec/allcodecs.c
> @@ -283,6 +283,7 @@ void avcodec_register_all(void)
>      REGISTER_DECODER(VP6F,              vp6f);
>      REGISTER_DECODER(VP8,               vp8);
>      REGISTER_DECODER(VQA,               vqa);
> +    REGISTER_DECODER(WEBP,              webp);
>      REGISTER_ENCDEC (WMV1,              wmv1);
>      REGISTER_ENCDEC (WMV2,              wmv2);
>      REGISTER_DECODER(WMV3,              wmv3);
> diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
> index c3bd534..1b5f9d4 100644
> --- a/libavcodec/avcodec.h
> +++ b/libavcodec/avcodec.h
> @@ -292,6 +292,7 @@ enum AVCodecID {
>      AV_CODEC_ID_MVC1       = MKBETAG('M','V','C','1'),
>      AV_CODEC_ID_MVC2       = MKBETAG('M','V','C','2'),
>      AV_CODEC_ID_SNOW       = MKBETAG('S','N','O','W'),
> +    AV_CODEC_ID_WEBP       = MKBETAG('W','E','B','P'),
>
>      /* various PCM "codecs" */
>      AV_CODEC_ID_FIRST_AUDIO = 0x10000,     ///< A dummy id pointing at
> the start of audio codecs
> diff --git a/libavcodec/codec_desc.c b/libavcodec/codec_desc.c
> index ded09c9..2b3eed7 100644
> --- a/libavcodec/codec_desc.c
> +++ b/libavcodec/codec_desc.c
> @@ -1038,6 +1038,13 @@ static const AVCodecDescriptor codec_descriptors[]
> = {
>          .props     = AV_CODEC_PROP_LOSSY,
>      },
>      {
> +        .id        = AV_CODEC_ID_WEBP,
> +        .type      = AVMEDIA_TYPE_VIDEO,
> +        .name      = "webp",
> +        .long_name = NULL_IF_CONFIG_SMALL("WebP"),
> +        .props     = AV_CODEC_PROP_LOSSY,
> +    },
> +    {
>          .id        = AV_CODEC_ID_PICTOR,
>          .type      = AVMEDIA_TYPE_VIDEO,
>          .name      = "pictor",
> diff --git a/libavcodec/vp8.c b/libavcodec/vp8.c
> index ac929d0..1ab76b5 100644
> --- a/libavcodec/vp8.c
> +++ b/libavcodec/vp8.c
> @@ -2094,6 +2094,52 @@ static int
> vp8_decode_update_thread_context(AVCodecContext *dst, const AVCodecCo
>      return 0;
>  }
>
> +static unsigned apply_padding(unsigned size) { return size + (size & 1); }
> +
> +static int webp_decode_frame(AVCodecContext *avctx, void *data, int
> *data_size,
> +                             AVPacket *avpkt)
> +{
> +    const uint8_t *buf = avpkt->data;
> +    int buf_size       = avpkt->size;
> +    AVPacket pkt       = *avpkt;
> +
> +    if (buf_size >= 16
> +        && AV_RL32(buf   ) == AV_RL32("RIFF")
> +        && AV_RL32(buf+ 8) == AV_RL32("WEBP")) {
> +        unsigned riff_size = apply_padding(AV_RL32(buf+4)) + 8;
> +        buf += 12;   // Skip over main header
> +        buf_size -= 12;
> +        if (buf_size < 8 || riff_size < 8) {
> +            av_log(avctx, AV_LOG_ERROR, "Incomplete header.\n");
> +            return AVERROR_INVALIDDATA;
> +        }
> +        if (AV_RL32(buf) == AV_RL32("VP8L")) {
> +            av_log(avctx, AV_LOG_ERROR, "Unsupported WebP lossless
> format.\n");
> +            return AVERROR_PATCHWELCOME;
> +        }
> +        if (AV_RL32(buf) == AV_RL32("VP8X") && AV_RL32(buf+4) <
> (unsigned)buf_size) {
> +            unsigned size = apply_padding(AV_RL32(buf+4) + 8);
> +            buf      += size;
> +            buf_size -= size;
> +        }
> +        if (buf_size >= 8
> +            && AV_RL32(buf) == AV_RL32("ALPH") && AV_RL32(buf+4) <
> (unsigned)buf_size) {
> +            unsigned size = apply_padding(AV_RL32(buf+4) + 8);
> +            buf      += size;
> +            buf_size -= size;
> +            av_log(avctx, AV_LOG_WARNING, "Skipping alpha plane\n");
> +        }
> +        if (buf_size >= 8 && AV_RL32(buf) == AV_RL32("VP8 ")) {
> +            buf      += 8;
> +            buf_size -= 8;
> +        }
> +    }
> +    pkt.data = buf;
> +    pkt.size = buf_size;
> +
> +    return vp8_decode_frame(avctx, data, data_size, &pkt);
> +}
> +
>  AVCodec ff_vp8_decoder = {
>      .name                  = "vp8",
>      .type                  = AVMEDIA_TYPE_VIDEO,
> @@ -2108,3 +2154,18 @@ AVCodec ff_vp8_decoder = {
>      .init_thread_copy      =
> ONLY_IF_THREADS_ENABLED(vp8_decode_init_thread_copy),
>      .update_thread_context =
> ONLY_IF_THREADS_ENABLED(vp8_decode_update_thread_context),
>  };
> +
> +AVCodec ff_webp_decoder = {
> +    .name                  = "webp",
> +    .type                  = AVMEDIA_TYPE_VIDEO,
> +    .id                    = AV_CODEC_ID_WEBP,
> +    .priv_data_size        = sizeof(VP8Context),
> +    .init                  = vp8_decode_init,
> +    .close                 = vp8_decode_free,
> +    .decode                = webp_decode_frame,
> +    .capabilities          = CODEC_CAP_DR1 | CODEC_CAP_FRAME_THREADS |
> CODEC_CAP_SLICE_THREADS,
> +    .flush                 = vp8_decode_flush,
> +    .long_name             = NULL_IF_CONFIG_SMALL("WebP"),
> +    .init_thread_copy      =
> ONLY_IF_THREADS_ENABLED(vp8_decode_init_thread_copy),
> +    .update_thread_context =
> ONLY_IF_THREADS_ENABLED(vp8_decode_update_thread_context),
> +};
> --
> 1.7.9.5
>
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