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authorGilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>2015-02-13 22:51:34 +0100
committerMichael Niedermayer <michaelni@gmx.at>2015-02-14 20:13:52 +0100
commit3eec775b211c5fd00300e2042ae8f116293e5d55 (patch)
tree2e3a6d0b73f41ba424336f2be90c03dd41cb39c8 /libavformat/rtpdec_ac3.c
parent22470510d1f9441e848bbe107c7963b6d492b47f (diff)
downloadffmpeg-3eec775b211c5fd00300e2042ae8f116293e5d55.tar.gz
avformat/rtpdec_ac3: add AC3 RTP depacketization (RFC 4184)
Signed-off-by: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org> Reviewed-by: Thomas Volkert <silvo@gmx.net> Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Diffstat (limited to 'libavformat/rtpdec_ac3.c')
-rw-r--r--libavformat/rtpdec_ac3.c157
1 files changed, 157 insertions, 0 deletions
diff --git a/libavformat/rtpdec_ac3.c b/libavformat/rtpdec_ac3.c
new file mode 100644
index 0000000000..7454a9af13
--- /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@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,
+};