[FFmpeg-devel] [PATCH 2/3] sbc: add parser for SBC

Aurelien Jacobs aurel at gnuage.org
Mon Nov 6 03:09:21 EET 2017


On Sun, Nov 05, 2017 at 11:43:37PM +0000, Rostislav Pehlivanov wrote:
> On 5 November 2017 at 23:35, Aurelien Jacobs <aurel at gnuage.org> wrote:
> 
> > ---
> >  libavcodec/Makefile     |   2 +
> >  libavcodec/allcodecs.c  |   2 +
> >  libavcodec/sbc_parser.c | 135 ++++++++++++++++++++++++++++++
> > ++++++++++++++++++
> >  3 files changed, 139 insertions(+)
> >  create mode 100644 libavcodec/sbc_parser.c
> >
> > diff --git a/libavcodec/Makefile b/libavcodec/Makefile
> > index 17648a1c3d..a15573748d 100644
> > --- a/libavcodec/Makefile
> > +++ b/libavcodec/Makefile
> > @@ -994,11 +994,13 @@ OBJS-$(CONFIG_PNG_PARSER)              +=
> > png_parser.o
> >  OBJS-$(CONFIG_MPEGAUDIO_PARSER)        += mpegaudio_parser.o
> >  OBJS-$(CONFIG_MPEGVIDEO_PARSER)        += mpegvideo_parser.o    \
> >                                            mpeg12.o mpeg12data.o
> > +OBJS-$(CONFIG_MSBC_PARSER)             += sbc_parser.o
> >  OBJS-$(CONFIG_OPUS_PARSER)             += opus_parser.o opus.o
> > vorbis_data.o
> >  OBJS-$(CONFIG_PNG_PARSER)              += png_parser.o
> >  OBJS-$(CONFIG_PNM_PARSER)              += pnm_parser.o pnm.o
> >  OBJS-$(CONFIG_RV30_PARSER)             += rv34_parser.o
> >  OBJS-$(CONFIG_RV40_PARSER)             += rv34_parser.o
> > +OBJS-$(CONFIG_SBC_PARSER)              += sbc_parser.o
> >  OBJS-$(CONFIG_SIPR_PARSER)             += sipr_parser.o
> >  OBJS-$(CONFIG_TAK_PARSER)              += tak_parser.o tak.o
> >  OBJS-$(CONFIG_VC1_PARSER)              += vc1_parser.o vc1.o vc1data.o  \
> > diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
> > index 95cf67ce20..02d241c4f3 100644
> > --- a/libavcodec/allcodecs.c
> > +++ b/libavcodec/allcodecs.c
> > @@ -717,11 +717,13 @@ static void register_all(void)
> >      REGISTER_PARSER(MPEG4VIDEO,         mpeg4video);
> >      REGISTER_PARSER(MPEGAUDIO,          mpegaudio);
> >      REGISTER_PARSER(MPEGVIDEO,          mpegvideo);
> > +    REGISTER_PARSER(MSBC,               msbc);
> >      REGISTER_PARSER(OPUS,               opus);
> >      REGISTER_PARSER(PNG,                png);
> >      REGISTER_PARSER(PNM,                pnm);
> >      REGISTER_PARSER(RV30,               rv30);
> >      REGISTER_PARSER(RV40,               rv40);
> > +    REGISTER_PARSER(SBC,                sbc);
> >      REGISTER_PARSER(SIPR,               sipr);
> >      REGISTER_PARSER(TAK,                tak);
> >      REGISTER_PARSER(VC1,                vc1);
> > diff --git a/libavcodec/sbc_parser.c b/libavcodec/sbc_parser.c
> > new file mode 100644
> > index 0000000000..278ac6f84f
> > --- /dev/null
> > +++ b/libavcodec/sbc_parser.c
> > @@ -0,0 +1,135 @@
> > +/*
> > + * SBC parser
> > + *
> > + * Copyright (C) 2017  Aurelien Jacobs <aurel at gnuage.org>
> > + *
> > + * 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
> > + */
> > +
> > +#include "sbc.h"
> > +#include "parser.h"
> > +
> > +typedef struct SBCParseContext {
> > +    ParseContext pc;
> > +    uint8_t header[3];
> > +    int header_size;
> > +    int buffered_size;
> > +} SBCParseContext;
> > +
> > +static int sbc_parse_header(AVCodecParserContext *s, AVCodecContext
> > *avctx,
> > +                            const uint8_t *data, size_t len)
> > +{
> > +    static const int sample_rates[4] = { 16000, 32000, 44100, 48000 };
> > +    int sr, blocks, mode, subbands, bitpool, channels, joint;
> > +    int length;
> > +
> > +    if (len < 3)
> > +        return -1;
> > +
> > +    if (data[0] == MSBC_SYNCWORD && data[1] == 0 && data[2] == 0) {
> > +        avctx->channels = 1;
> > +        avctx->sample_fmt = AV_SAMPLE_FMT_S16;
> > +        avctx->sample_rate = 16000;
> > +        avctx->frame_size = 120;
> > +        s->duration = avctx->frame_size;
> > +        return 57;
> > +    }
> > +
> > +    if (data[0] != SBC_SYNCWORD)
> > +        return -2;
> > +
> > +    sr       =   (data[1] >> 6) & 0x03;
> > +    blocks   = (((data[1] >> 4) & 0x03) + 1) << 2;
> > +    mode     =   (data[1] >> 2) & 0x03;
> > +    subbands = (((data[1] >> 0) & 0x01) + 1) << 2;
> > +    bitpool  = data[2];
> > +
> > +    channels = mode == SBC_MODE_MONO ? 1 : 2;
> > +    joint    = mode == SBC_MODE_JOINT_STEREO;
> > +
> > +    length = 4 + (subbands * channels) / 2;
> > +    if (channels == 1 || mode == SBC_MODE_DUAL_CHANNEL)
> > +        length += ((channels * blocks * bitpool) + 7) / 8;
> > +    else
> > +        length += (((joint ? subbands : 0) + blocks * bitpool) + 7) / 8;
> > +
> > +    avctx->channels = channels;
> > +    avctx->sample_fmt = AV_SAMPLE_FMT_S16;
> > +    avctx->sample_rate = sample_rates[sr];
> > +    avctx->frame_size = subbands * blocks;
> > +    s->duration = avctx->frame_size;
> > +    return length;
> > +}
> > +
> > +static int sbc_parse(AVCodecParserContext *s, AVCodecContext *avctx,
> > +                     const uint8_t **poutbuf, int *poutbuf_size,
> > +                     const uint8_t *buf, int buf_size)
> > +{
> > +    SBCParseContext *pc = s->priv_data;
> > +    int next;
> > +
> > +    if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
> > +        next = buf_size;
> > +    } else {
> > +        if (pc->header_size) {
> > +            memcpy(pc->header + pc->header_size, buf,
> > +                   sizeof(pc->header) - pc->header_size);
> > +            next = sbc_parse_header(s, avctx, pc->header,
> > sizeof(pc->header))
> > +                 - pc->buffered_size;
> > +            pc->header_size = 0;
> > +        } else {
> > +            next = sbc_parse_header(s, avctx, buf, buf_size);
> > +            if (next >= buf_size)
> > +                next = -1;
> > +        }
> > +
> > +        if (next < 0) {
> > +            pc->header_size = FFMIN(sizeof(pc->header), buf_size);
> > +            memcpy(pc->header, buf, pc->header_size);
> > +            pc->buffered_size = buf_size;
> > +            next = END_NOT_FOUND;
> > +        }
> > +
> > +        if (ff_combine_frame(&pc->pc, next, &buf, &buf_size) < 0) {
> > +            *poutbuf      = NULL;
> > +            *poutbuf_size = 0;
> > +            return buf_size;
> > +        }
> > +    }
> > +
> > +    *poutbuf      = buf;
> > +    *poutbuf_size = buf_size;
> > +    return next;
> > +}
> > +
> > +#if CONFIG_SBC_PARSER
> > +AVCodecParser ff_sbc_parser = {
> > +    .codec_ids      = { AV_CODEC_ID_SBC },
> > +    .priv_data_size = sizeof(SBCParseContext),
> > +    .parser_parse   = sbc_parse,
> > +    .parser_close   = ff_parse_close,
> > +};
> > +#endif
> > +
> > +#if CONFIG_MSBC_PARSER
> > +AVCodecParser ff_msbc_parser = {
> > +    .codec_ids      = { AV_CODEC_ID_MSBC },
> > +    .priv_data_size = sizeof(SBCParseContext),
> > +    .parser_parse   = sbc_parse,
> > +    .parser_close   = ff_parse_close,
> > +};
> > +#endif
> >
> 
> 
> Remove the msbc parser and add its codec ID to ff_sbc_parser.codec_ids,
> since there's no difference in parsing between the two.

Right, I will change this.

--
Aurel


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