[FFmpeg-devel] [PATCH 2/4] lavd: make lavfi device export the metadata up to the AVFrame.

Stefano Sabatini stefasab at gmail.com
Sun Oct 14 13:14:07 CEST 2012


On date Saturday 2012-10-13 16:36:55 +0200, Clément Bœsch encoded:
> On Thu, Oct 11, 2012 at 11:22:53PM +0200, Clément Bœsch wrote:
> > On Wed, Oct 10, 2012 at 12:55:11AM +0200, Clément Bœsch wrote:
> > > TODO: lavc minor bump?
> > > ---
> > >  libavcodec/avcodec.h | 1 +
> > >  libavcodec/utils.c   | 7 +++++++
> > >  libavdevice/lavfi.c  | 9 +++++++++
> > >  3 files changed, 17 insertions(+)
> > > 
> > 
> > After a discussion on IRC, we are considering something more complex but
> > more solid:

> >  - in lavd/lavfi: convert each buffer ref metadata key/value into side
> >    data type "meta" like let's say "key\0value\0"
> >  - put some metadata dict in the raw a/v contexts (just like the tiff
> >    decoder), and construct it based on the "meta" side data of each
> >    packets. (AVCodecInternal was also mentioned, I need to look how it
> >    helps)

Are these two solutions complementary or mutually exclusive?

> > 
> 
> Here we go, here is the V2. Should be better than the previous hack.
> 
> -- 
> Clément B.

> From 5924da49cf4158f7ee4cdbfea22b822137b05be3 Mon Sep 17 00:00:00 2001
> From: =?UTF-8?q?Cl=C3=A9ment=20B=C5=93sch?= <ubitux at gmail.com>
> Date: Tue, 9 Oct 2012 23:01:07 +0200
> Subject: [PATCH 2/4] lavd: make lavfi device export the metadata up to the
>  AVFrame.
> 
> TODO: lavc minor bump + APIChanges
> ---
>  libavcodec/avcodec.h  |  6 ++++++
>  libavcodec/internal.h |  7 +++++++
>  libavcodec/pcm.c      |  8 ++++++--
>  libavcodec/rawdec.c   |  6 ++++++
>  libavcodec/utils.c    | 22 ++++++++++++++++++++++
>  libavdevice/lavfi.c   | 20 ++++++++++++++++++++
>  6 files changed, 67 insertions(+), 2 deletions(-)
> 
> diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
> index 3c3dad3..9370a56 100644
> --- a/libavcodec/avcodec.h
> +++ b/libavcodec/avcodec.h
> @@ -941,6 +941,12 @@ enum AVPacketSideDataType {
>       * @endcode
>       */
>      AV_PKT_DATA_JP_DUALMONO,
> +
> +    /**
> +     * A list of zero terminated key/value strings. There is no end marker for
> +     * the list, so it is required to rely on the side data size to stop.
> +     */
> +    AV_PKT_DATA_METATAGS,

Nit: I don't like METATAGS, "META" means "beyond" (like in
"metaphyisics") or "over" (like in "metamathematics"), meta-tags is
abusing contraction rules resulting in semantical confusion. I
suggest one of these:
AV_PKT_DATA_METADATA_TAGS
AV_PKT_DATA_METADATA
AV_PKT_DATA_TAGS

I prefer the longest/more explicit, but I'm OK with the others as
well.

>  };
>  
>  typedef struct AVPacket {
> diff --git a/libavcodec/internal.h b/libavcodec/internal.h
> index ed38c61..60573d4 100644
> --- a/libavcodec/internal.h
> +++ b/libavcodec/internal.h
> @@ -178,4 +178,11 @@ int ff_get_logical_cpus(AVCodecContext *avctx);
>  
>  int avpriv_h264_has_num_reorder_frames(AVCodecContext *avctx);
>  
> +/**
> + * Construct a new metadata dictionary in the given frame from a
> + * AV_PKT_DATA_METATAGS side data of the provided packet.
> + * @note the frame->metadata is always destroyed
> + */
> +int ff_set_metadata_from_side_data(AVFrame *frame, AVPacket *pkt);
> +
>  #endif /* AVCODEC_INTERNAL_H */
> diff --git a/libavcodec/pcm.c b/libavcodec/pcm.c
> index dd626dc..d9463e8 100644
> --- a/libavcodec/pcm.c
> +++ b/libavcodec/pcm.c
> @@ -58,8 +58,10 @@ static av_cold int pcm_encode_init(AVCodecContext *avctx)
>  
>  static av_cold int pcm_encode_close(AVCodecContext *avctx)
>  {
> -    av_freep(&avctx->coded_frame);
> -
> +    if (avctx->coded_frame) {
> +        av_dict_free(&avctx->coded_frame->metadata);
> +        av_freep(&avctx->coded_frame);
> +    }
>      return 0;
>  }
>  
> @@ -470,6 +472,8 @@ static int pcm_decode_frame(AVCodecContext *avctx, void *data,
>          return -1;
>      }
>  
> +    ff_set_metadata_from_side_data(&s->frame, avpkt);
> +
>      *got_frame_ptr   = 1;
>      *(AVFrame *)data = s->frame;
>  
> diff --git a/libavcodec/rawdec.c b/libavcodec/rawdec.c
> index d426f43..2275029 100644
> --- a/libavcodec/rawdec.c
> +++ b/libavcodec/rawdec.c
> @@ -25,6 +25,7 @@
>   */
>  
>  #include "avcodec.h"
> +#include "internal.h"
>  #include "raw.h"
>  #include "libavutil/avassert.h"
>  #include "libavutil/common.h"
> @@ -258,6 +259,9 @@ static int raw_decode(AVCodecContext *avctx,
>          }
>      }
>  
> +    ff_set_metadata_from_side_data(avctx->coded_frame, avpkt);
> +    frame->metadata = avctx->coded_frame->metadata;
> +
>      *data_size = sizeof(AVPicture);
>      return buf_size;
>  }
> @@ -266,6 +270,8 @@ static av_cold int raw_close_decoder(AVCodecContext *avctx)
>  {
>      RawVideoContext *context = avctx->priv_data;
>  
> +    if (avctx->coded_frame)
> +        av_dict_free(&avctx->coded_frame->metadata);
>      av_freep(&context->buffer);
>      return 0;
>  }
> diff --git a/libavcodec/utils.c b/libavcodec/utils.c
> index 183776a..d987e45 100644
> --- a/libavcodec/utils.c
> +++ b/libavcodec/utils.c
> @@ -2590,3 +2590,25 @@ int avcodec_is_open(AVCodecContext *s)
>  {
>      return !!s->internal;
>  }
> +
> +int ff_set_metadata_from_side_data(AVFrame *frame, AVPacket *pkt)
> +{
> +    int size;
> +    const uint8_t *side_meta;
> +    const uint8_t *end;
> +
> +    av_dict_free(&frame->metadata);
> +    side_meta = av_packet_get_side_data(pkt, AV_PKT_DATA_METATAGS, &size);
> +    if (!side_meta)
> +        return 0;
> +    end = side_meta + size;

> +    while (side_meta < end) {
> +        const uint8_t *key = side_meta;
> +        const uint8_t *val = side_meta + strlen(key) + 1;
> +        int ret = av_dict_set(&frame->metadata, key, val, 0);
> +        if (ret < 0)
> +            return ret;
> +        side_meta = val + strlen(val) + 1;
> +    }
> +    return 0;
> +}
> diff --git a/libavdevice/lavfi.c b/libavdevice/lavfi.c
> index 944794f..faf918a 100644
> --- a/libavdevice/lavfi.c
> +++ b/libavdevice/lavfi.c
> @@ -27,6 +27,7 @@
>  
>  #include "float.h"              /* DBL_MIN, DBL_MAX */
>  
> +#include "libavutil/bprint.h"
>  #include "libavutil/log.h"
>  #include "libavutil/mem.h"
>  #include "libavutil/opt.h"
> @@ -339,6 +340,25 @@ static int lavfi_read_packet(AVFormatContext *avctx, AVPacket *pkt)
>          memcpy(pkt->data, ref->data[0], size);
>      }
>  
> +    if (ref->metadata) {
> +        uint8_t *meta;
> +        AVDictionaryEntry *e = NULL;
> +        AVBPrint meta_buf;
> +
> +        av_bprint_init(&meta_buf, 0, AV_BPRINT_SIZE_UNLIMITED);
> +        while ((e = av_dict_get(ref->metadata, "", e, AV_DICT_IGNORE_SUFFIX))) {
> +            av_bprintf(&meta_buf, "%s", e->key);
> +            av_bprint_chars(&meta_buf, '\0', 1);
> +            av_bprintf(&meta_buf, "%s", e->value);
> +            av_bprint_chars(&meta_buf, '\0', 1);
> +        }
> +        meta = av_packet_new_side_data(pkt, AV_PKT_DATA_METATAGS, meta_buf.len);
> +        if (!meta)
> +            return AVERROR(ENOMEM);

Leak meta_buf is !meta (as noted by Nicolas).

[...]
-- 
FFmpeg = Foolish and Fanciful MultiPurpose Elaborated Gladiator


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