[FFmpeg-devel] [PATCH] png parser

[Michael Niedermayer]

On Mon, Jun 01, 2009 at 12:27:52PM +0200, Peter Holik wrote:
> Hi!
> 
> I've now reworked my patch to really parse a png for end of frame.
> 
> Now you can filter out png's of any stream like
> 
> cat garbage a.png garbage b.png garbage | ffmpeg -f image2pipe -vcodec png -i - c%d.png
> 
> cu Peter
>  Makefile     |    1 
>  allcodecs.c  |    1 
>  png_parser.c |  124 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 126 insertions(+)
> 63f7cd1bb826726f1d2a9e7254410cd7ec98a81c  png-parser.patch
> diff --git a/libavcodec/Makefile b/libavcodec/Makefile
> index 14ef9f4..189231b 100644
> --- a/libavcodec/Makefile
> +++ b/libavcodec/Makefile
> @@ -411,6 +411,7 @@ OBJS-$(CONFIG_MLP_PARSER)              += mlp_parser.o mlp.o
>  OBJS-$(CONFIG_MPEG4VIDEO_PARSER)       += mpeg4video_parser.o h263.o mpeg12data.o mpegvideo.o error_resilience.o
>  OBJS-$(CONFIG_MPEGAUDIO_PARSER)        += mpegaudio_parser.o mpegaudiodecheader.o mpegaudiodata.o
>  OBJS-$(CONFIG_MPEGVIDEO_PARSER)        += mpegvideo_parser.o mpeg12.o mpeg12data.o mpegvideo.o error_resilience.o
> +OBJS-$(CONFIG_PNG_PARSER)              += png_parser.o
>  OBJS-$(CONFIG_PNM_PARSER)              += pnm_parser.o pnm.o
>  OBJS-$(CONFIG_VC1_PARSER)              += vc1_parser.o
>  OBJS-$(CONFIG_VP3_PARSER)              += vp3_parser.o
> diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
> index e8d5d27..362021f 100644
> --- a/libavcodec/allcodecs.c
> +++ b/libavcodec/allcodecs.c
> @@ -334,6 +334,7 @@ void avcodec_register_all(void)
>      REGISTER_PARSER  (MPEG4VIDEO, mpeg4video);
>      REGISTER_PARSER  (MPEGAUDIO, mpegaudio);
>      REGISTER_PARSER  (MPEGVIDEO, mpegvideo);
> +    REGISTER_PARSER  (PNG, png);
>      REGISTER_PARSER  (PNM, pnm);
>      REGISTER_PARSER  (VC1, vc1);
>      REGISTER_PARSER  (VP3, vp3);
> diff --git a/libavcodec/png_parser.c b/libavcodec/png_parser.c
> new file mode 100644
> index 0000000..64f2356
> --- /dev/null
> +++ b/libavcodec/png_parser.c
> @@ -0,0 +1,124 @@
> +/*
> + * PNG parser
> + * Copyright (c) 2009 Peter Holik
> + *
> + * This file is part of FFmpeg.
> + *
> + * FFmpeg is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later version.
> + *
> + * FFmpeg is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with FFmpeg; if not, write to the Free Software
> + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
> + */
> +
> +/**
> + * @file libavcodec/png_parser.c
> + * PNG parser
> + */
> +
> +#include "parser.h"
> +#include "bytestream.h"
> +#include "png.h"
> +
> +static int png_parse(AVCodecParserContext *s, AVCodecContext *avctx,
> +                     const uint8_t **poutbuf, int *poutbuf_size,
> +                     const uint8_t *buf, int buf_size)
> +{
> +    ParseContext *pc = s->priv_data;
> +    uint8_t *bytestream;
> +    uint8_t *bytestream_start;
> +    uint8_t *bytestream_end;
> +
> +    /* EOF considered as end of frame */
> +    if (buf_size == 0)
> +        goto flush;
> +
> +    *poutbuf      = NULL;
> +    *poutbuf_size = 0;
> +
> +    /* first add new buffer to parsebuffer */
> +    bytestream_start = av_fast_realloc(pc->buffer, &pc->buffer_size,
> +                          pc->index + buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
> +    if(!bytestream_start)
> +        goto fail;
> +    pc->buffer = bytestream_start;
> +    memcpy(&pc->buffer[pc->index], buf, buf_size);

mandatory copying is unacceptable
the case where each input is exactly a png frame for example should
be free of any timeconsuming operation

maybe ff_combine_frame() would be usefull

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

The bravest are surely those who have the clearest vision
of what is before them, glory and danger alike, and yet
notwithstanding go out to meet it. -- Thucydides
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 189 bytes
Desc: Digital signature
URL: <http://lists.mplayerhq.hu/pipermail/ffmpeg-devel/attachments/20090603/8528bfd8/attachment.pgp>