libavformat: add robust MPEG audio depacketization (RFC 5219)

Signed-off-by: Martin Storsjö <martin@martin.st>

Changelog

@@ -17,6 +17,7 @@ version <next>:
 - Intel QSV-accelerated H.264 decoding
 - DSS SP decoder and DSS demuxer
 - RTP depacketizer for AC3 payload format (RFC 4184)
+- RTP depacketizer for loss tolerant payload format for MP3 audio (RFC 5219)
 
 
 version 11:

libavformat/Makefile

@@ -40,6 +40,7 @@ OBJS-$(CONFIG_RTPDEC)                    += rdt.o                       \
                                             rtpdec_ilbc.o               \
                                             rtpdec_jpeg.o               \
                                             rtpdec_latm.o               \
+                                            rtpdec_mpa_robust.o         \
                                             rtpdec_mpeg12.o             \
                                             rtpdec_mpeg4.o              \
                                             rtpdec_mpegts.o             \

libavformat/rtpdec.c

@@ -78,6 +78,7 @@ void ff_register_rtp_dynamic_payload_handlers(void)
     ff_register_dynamic_payload_handler(&ff_mp4a_latm_dynamic_handler);
     ff_register_dynamic_payload_handler(&ff_mp4v_es_dynamic_handler);
     ff_register_dynamic_payload_handler(&ff_mpeg_audio_dynamic_handler);
+    ff_register_dynamic_payload_handler(&ff_mpeg_audio_robust_dynamic_handler);
     ff_register_dynamic_payload_handler(&ff_mpeg_video_dynamic_handler);
     ff_register_dynamic_payload_handler(&ff_mpeg4_generic_dynamic_handler);
     ff_register_dynamic_payload_handler(&ff_mpegts_dynamic_handler);

libavformat/rtpdec_formats.h

@@ -61,6 +61,7 @@ extern RTPDynamicProtocolHandler ff_jpeg_dynamic_handler;
 extern RTPDynamicProtocolHandler ff_mp4a_latm_dynamic_handler;
 extern RTPDynamicProtocolHandler ff_mp4v_es_dynamic_handler;
 extern RTPDynamicProtocolHandler ff_mpeg_audio_dynamic_handler;
+extern RTPDynamicProtocolHandler ff_mpeg_audio_robust_dynamic_handler;
 extern RTPDynamicProtocolHandler ff_mpeg_video_dynamic_handler;
 extern RTPDynamicProtocolHandler ff_mpeg4_generic_dynamic_handler;
 extern RTPDynamicProtocolHandler ff_mpegts_dynamic_handler;

libavformat/rtpdec_mpa_robust.c

+/*
+ * RTP parser for loss tolerant payload format for MP3 audio (RFC 5219)
+ * Copyright (c) 2015 Gilles Chanteperdrix <gch@xenomai.org>
+ *
+ * This file is part of Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "libavutil/attributes.h"
+#include "libavutil/intreadwrite.h"
+
+#include "rtpdec_formats.h"
+
+struct PayloadContext {
+    unsigned adu_size;
+    unsigned cur_size;
+    uint32_t timestamp;
+    uint8_t *split_buf;
+    int split_pos, split_buf_size, split_pkts;
+    AVIOContext *fragment;
+};
+
+static av_cold int mpa_robust_init(AVFormatContext *ctx, int st_index,
+                                   PayloadContext *data)
+{
+    if (st_index < 0)
+        return 0;
+    ctx->streams[st_index]->need_parsing = AVSTREAM_PARSE_HEADERS;
+    return 0;
+}
+
+static PayloadContext *mpa_robust_new_context(void)
+{
+    return av_mallocz(sizeof(PayloadContext));
+}
+
+static inline void free_fragment(PayloadContext *data)
+{
+    if (data->fragment) {
+        uint8_t *p;
+        avio_close_dyn_buf(data->fragment, &p);
+        av_free(p);
+        data->fragment = NULL;
+    }
+}
+
+static void mpa_robust_free_context(PayloadContext *data)
+{
+    free_fragment(data);
+    av_free(data->split_buf);
+    av_free(data);
+}
+
+static int mpa_robust_parse_rtp_header(AVFormatContext *ctx,
+                                       const uint8_t *buf, int len,
+                                       unsigned *adu_size, unsigned *cont)
+{
+    unsigned header_size;
+
+    if (len < 2) {
+        av_log(ctx, AV_LOG_ERROR, "Invalid %d bytes packet\n", len);
+        return AVERROR_INVALIDDATA;
+    }
+
+    *cont = !!(buf[0] & 0x80);
+    if (!(buf[0] & 0x40)) {
+        header_size = 1;
+        *adu_size = buf[0] & ~0xc0;
+    } else {
+        header_size = 2;
+        *adu_size = AV_RB16(buf) & ~0xc000;
+    }
+
+    return header_size;
+}
+
+static int mpa_robust_parse_packet(AVFormatContext *ctx, PayloadContext *data,
+                                   AVStream *st, AVPacket *pkt,
+                                   uint32_t *timestamp, const uint8_t *buf,
+                                   int len, uint16_t seq, int flags)
+{
+    unsigned adu_size, continuation;
+    int err, header_size;
+
+    if (!buf) {
+        buf = &data->split_buf[data->split_pos];
+        len = data->split_buf_size - data->split_pos;
+
+        header_size = mpa_robust_parse_rtp_header(ctx, buf, len, &adu_size,
+                                                  &continuation);
+        if (header_size < 0) {
+            av_freep(&data->split_buf);
+            return header_size;
+        }
+        buf += header_size;
+        len -= header_size;
+
+        if (continuation || adu_size > len) {
+            av_freep(&data->split_buf);
+            av_log(ctx, AV_LOG_ERROR, "Invalid frame\n");
+            return AVERROR_INVALIDDATA;
+        }
+
+        if (av_new_packet(pkt, adu_size)) {
+            av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
+            return AVERROR(ENOMEM);
+        }
+
+        pkt->stream_index = st->index;
+        memcpy(pkt->data, buf, adu_size);
+
+        data->split_pos += adu_size;
+
+        if (data->split_pos == data->split_buf_size) {
+            av_freep(&data->split_buf);
+            return 0;
+        }
+
+        return 1;
+    }
+
+
+    header_size = mpa_robust_parse_rtp_header(ctx, buf, len, &adu_size,
+                                              &continuation);
+    if (header_size < 0)
+        return header_size;
+
+    buf += header_size;
+    len -= header_size;
+
+    if (!continuation && adu_size <= len) {
+        /* One or more complete frames */
+
+        if (av_new_packet(pkt, adu_size)) {
+            av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
+            return AVERROR(ENOMEM);
+        }
+
+        pkt->stream_index = st->index;
+        memcpy(pkt->data, buf, adu_size);
+
+        buf += adu_size;
+        len -= adu_size;
+        if (len) {
+            data->split_buf_size = len;
+            data->split_buf = av_malloc(data->split_buf_size);
+            data->split_pos = 0;
+            if (!data->split_buf) {
+                av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
+                av_free_packet(pkt);
+                return AVERROR(ENOMEM);
+            }
+            memcpy(data->split_buf, buf, data->split_buf_size);
+            return 1;
+        }
+        return 0;
+    } else if (!continuation) { /* && adu_size > len */
+        /* First fragment */
+        free_fragment(data);
+
+        data->adu_size = adu_size;
+        data->cur_size = len;
+        data->timestamp = *timestamp;
+
+        err = avio_open_dyn_buf(&data->fragment);
+        if (err < 0)
+            return err;
+
+        avio_write(data->fragment, buf, len);
+        return AVERROR(EAGAIN);
+    }
+    /* else continuation == 1 */
+
+    /* 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 (adu_size = data->adu_size ||
+        data->timestamp != *timestamp) {
+        free_fragment(data);
+        av_log(ctx, AV_LOG_ERROR, "Invalid packet received\n");
+        return AVERROR_INVALIDDATA;
+    }
+
+    avio_write(data->fragment, buf, len);
+    data->cur_size += len;
+
+    if (data->cur_size < data->adu_size)
+        return AVERROR(EAGAIN);
+
+    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.\n");
+        return err;
+    }
+
+    return 0;
+}
+
+RTPDynamicProtocolHandler ff_mpeg_audio_robust_dynamic_handler = {
+    .codec_type        = AVMEDIA_TYPE_AUDIO,
+    .codec_id          = AV_CODEC_ID_MP3ADU,
+    .init              = mpa_robust_init,
+    .alloc             = mpa_robust_new_context,
+    .free              = mpa_robust_free_context,
+    .parse_packet      = mpa_robust_parse_packet,
+    .enc_name          = "mpa-robust",
+};

libavformat/version.h

@@ -30,7 +30,7 @@
 #include "libavutil/version.h"
 
 #define LIBAVFORMAT_VERSION_MAJOR 56
-#define LIBAVFORMAT_VERSION_MINOR 13
+#define LIBAVFORMAT_VERSION_MINOR 14
 #define LIBAVFORMAT_VERSION_MICRO  0
 
 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \