[FFmpeg-devel] [PATCH 3/3] avformat/rtpdec_ac3: add AC3 RTP depacketization (RFC 4184)

Thomas Volkert silvo at gmx.net
Sat Feb 14 19:21:04 CET 2015


On 02/13/2015 10:51 PM, Gilles Chanteperdrix wrote:
> Signed-off-by: Gilles Chanteperdrix <gilles.chanteperdrix at xenomai.org>
> ---
>   Changelog                    |   1 +
>   MAINTAINERS                  |   1 +
>   libavformat/Makefile         |   1 +
>   libavformat/rtpdec.c         |   1 +
>   libavformat/rtpdec_ac3.c     | 157 +++++++++++++++++++++++++++++++++++++++++++
>   libavformat/rtpdec_formats.h |   1 +
>   libavformat/version.h        |   4 +-
>   7 files changed, 164 insertions(+), 2 deletions(-)
>   create mode 100644 libavformat/rtpdec_ac3.c
>
> diff --git a/Changelog b/Changelog
> index 775fc79..085fd17 100644
> --- a/Changelog
> +++ b/Changelog
> @@ -24,6 +24,7 @@ version <next>:
>   - ported softpulldown filter from libmpcodecs as repeatfields filter
>   - dcshift filter
>   - RTP parser for loss tolerant payload format for MP3 audio (RFC 5219)
> +- RTP parser for AC3 payload format (RFC 4184)
>   
>   
>   version 2.5:
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 13b211e..8430222 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -465,6 +465,7 @@ Muxers/Demuxers:
>     rmdec.c, rmenc.c                      Ronald S. Bultje, Kostya Shishkov
>     rtmp*                                 Kostya Shishkov
>     rtp.c, rtpenc.c                       Martin Storsjo
> +  rtpdec_ac3.*                          Gilles Chanteperdrix
>     rtpdec_h261.*, rtpenc_h261.*          Thomas Volkert
>     rtpdec_hevc.*, rtpenc_hevc.*          Thomas Volkert
>     rtpdec_asf.*                          Ronald S. Bultje
> diff --git a/libavformat/Makefile b/libavformat/Makefile
> index ec312ba..073a42d 100644
> --- a/libavformat/Makefile
> +++ b/libavformat/Makefile
> @@ -29,6 +29,7 @@ OBJS-$(CONFIG_RIFFENC)                   += riffenc.o
>   OBJS-$(CONFIG_RTPDEC)                    += rdt.o                       \
>                                               rtp.o                       \
>                                               rtpdec.o                    \
> +                                            rtpdec_ac3.o                \
>                                               rtpdec_amr.o                \
>                                               rtpdec_asf.o                \
>                                               rtpdec_g726.o               \
> diff --git a/libavformat/rtpdec.c b/libavformat/rtpdec.c
> index c632340..550da4a 100644
> --- a/libavformat/rtpdec.c
> +++ b/libavformat/rtpdec.c
> @@ -72,6 +72,7 @@ void ff_register_dynamic_payload_handler(RTPDynamicProtocolHandler *handler)
>   
>   void ff_register_rtp_dynamic_payload_handlers(void)
>   {
> +    ff_register_dynamic_payload_handler(&ff_ac3_dynamic_handler);
>       ff_register_dynamic_payload_handler(&ff_amr_nb_dynamic_handler);
>       ff_register_dynamic_payload_handler(&ff_amr_wb_dynamic_handler);
>       ff_register_dynamic_payload_handler(&ff_g726_16_dynamic_handler);
> diff --git a/libavformat/rtpdec_ac3.c b/libavformat/rtpdec_ac3.c
> new file mode 100644
> index 0000000..728f421
> --- /dev/null
> +++ b/libavformat/rtpdec_ac3.c
> @@ -0,0 +1,157 @@
> +/*
> + * RTP parser for AC3 payload format (RFC 4184)
> + * Copyright (c) 2015 Gilles Chanteperdrix <gch at xenomai.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 "avformat.h"
> +#include "rtpdec_formats.h"
> +
> +#define RTP_AC3_PAYLOAD_HEADER_SIZE 2
> +
> +struct PayloadContext {
> +    unsigned nr_frames;
> +    unsigned last_frame;
> +    uint32_t timestamp;
> +    AVIOContext *fragment;
> +};
> +
> +static av_cold int ac3_init(AVFormatContext *s, int st_index,
> +			PayloadContext *data)
> +{
> +    if (st_index < 0)
> +        return 0;
> +    s->streams[st_index]->need_parsing = AVSTREAM_PARSE_FULL;
> +    return 0;
> +}
> +
> +static PayloadContext *ac3_new_context(void)
> +{
> +    return av_mallocz(sizeof(PayloadContext));
> +}
> +
> +static inline void free_fragment_if_needed(PayloadContext *data)
> +{
> +    if (data->fragment) {
> +        uint8_t *p;
> +        avio_close_dyn_buf(data->fragment, &p);
> +        av_free(p);
> +        data->fragment = NULL;
> +    }
> +}
> +
> +static void ac3_free_context(PayloadContext *data)
> +{
> +    free_fragment_if_needed(data);
> +    av_free(data);
> +}
> +
> +static int ac3_handle_packet(AVFormatContext *ctx, PayloadContext *data,
> +                              AVStream *st, AVPacket *pkt, uint32_t *timestamp,
> +                              const uint8_t *buf, int len, uint16_t seq,
> +                              int flags)
> +{
> +    unsigned frame_type;
> +    unsigned nr_frames;
> +    int err;
> +
> +    if (len < RTP_AC3_PAYLOAD_HEADER_SIZE + 1) {
> +        av_log(ctx, AV_LOG_ERROR, "Invalid %d bytes packet\n", len);
> +        return AVERROR_INVALIDDATA;
> +    }
> +
> +    frame_type = buf[0] & 0x3;
> +    nr_frames = buf[1];
> +    buf += RTP_AC3_PAYLOAD_HEADER_SIZE;
> +    len -= RTP_AC3_PAYLOAD_HEADER_SIZE;
> +
> +    switch (frame_type) {
> +    case 0: /* One or more complete frames */
> +        if (!nr_frames) {
> +            av_log(ctx, AV_LOG_ERROR, "Invalid AC3 packet data\n");
> +            return AVERROR_INVALIDDATA;
> +        }
> +        if (av_new_packet(pkt, len)) {
> +            av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
> +            return AVERROR(ENOMEM);
> +        }
> +
> +        pkt->stream_index = st->index;
> +        memcpy(pkt->data, buf, len);
> +        return 0;
> +
> +    case 1:
> +    case 2: /* First fragment */
> +        free_fragment_if_needed(data);
> +
> +        data->last_frame = 1;
> +        data->nr_frames = nr_frames;
> +        err = avio_open_dyn_buf(&data->fragment);
> +        if (err < 0)
> +            return err;
> +
> +        avio_write(data->fragment, buf, len);
> +        data->timestamp = *timestamp;
> +        return AVERROR(EAGAIN);
> +
> +    case 3: /* Fragment other than first */
> +        if (!data->fragment) {
> +            av_log(ctx, AV_LOG_WARNING,
> +                   "Received packet without a start fragment; dropping.\n");
> +            return AVERROR(EAGAIN);
> +        }
> +        if (nr_frames != data->nr_frames ||
> +            data->timestamp != *timestamp) {
> +            free_fragment_if_needed(data);
> +            av_log(ctx, AV_LOG_ERROR, "Invalid packet received\n");
> +            return AVERROR_INVALIDDATA;
> +        }
> +
> +        avio_write(data->fragment, buf, len);
> +        data->last_frame++;
> +    }
> +
> +    if (!(flags & RTP_FLAG_MARKER))
> +        return AVERROR(EAGAIN);
> +
> +    if (data->last_frame != data->nr_frames) {
> +        free_fragment_if_needed(data);
> +        av_log(ctx, AV_LOG_ERROR, "Missed %d packets\n",
> +               data->nr_frames - data->last_frame);
> +        return AVERROR_INVALIDDATA;
> +    }
> +
> +    err = ff_rtp_finalize_packet(pkt, &data->fragment, st->index);
> +    if (err < 0) {
> +        av_log(ctx, AV_LOG_ERROR,
> +               "Error occurred when getting fragment buffer.");
> +        return err;
> +    }
> +
> +    return 0;
> +}
> +
> +RTPDynamicProtocolHandler ff_ac3_dynamic_handler = {
> +    .enc_name           = "ac3",
> +    .codec_type         = AVMEDIA_TYPE_AUDIO,
> +    .codec_id           = AV_CODEC_ID_AC3,
> +    .init               = ac3_init,
> +    .alloc              = ac3_new_context,
> +    .free               = ac3_free_context,
> +    .parse_packet       = ac3_handle_packet,
> +};
> diff --git a/libavformat/rtpdec_formats.h b/libavformat/rtpdec_formats.h
> index da22d70..b38cf1b 100644
> --- a/libavformat/rtpdec_formats.h
> +++ b/libavformat/rtpdec_formats.h
> @@ -35,6 +35,7 @@ int ff_h263_handle_packet(AVFormatContext *ctx, PayloadContext *data,
>                             AVStream *st, AVPacket *pkt, uint32_t *timestamp,
>                             const uint8_t *buf, int len, uint16_t seq, int flags);
>   
> +extern RTPDynamicProtocolHandler ff_ac3_dynamic_handler;
>   extern RTPDynamicProtocolHandler ff_amr_nb_dynamic_handler;
>   extern RTPDynamicProtocolHandler ff_amr_wb_dynamic_handler;
>   extern RTPDynamicProtocolHandler ff_g726_16_dynamic_handler;
> diff --git a/libavformat/version.h b/libavformat/version.h
> index 84749ec..f7fe97e 100644
> --- a/libavformat/version.h
> +++ b/libavformat/version.h
> @@ -30,8 +30,8 @@
>   #include "libavutil/version.h"
>   
>   #define LIBAVFORMAT_VERSION_MAJOR 56
> -#define LIBAVFORMAT_VERSION_MINOR  20
> -#define LIBAVFORMAT_VERSION_MICRO 102
> +#define LIBAVFORMAT_VERSION_MINOR  21
> +#define LIBAVFORMAT_VERSION_MICRO 103
>   
>   #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
>                                                  LIBAVFORMAT_VERSION_MINOR, \

Okay.

Best regards,
Thomas.


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