rtpenc: Merge the h264 and hevc packetizers

They share a great deal of common structure; only a few minor
bits in the headers differ.

This also fixes an off-by-one in sending of the last fragment
of large HEVC nals (where it previously sent len+2 bytes, even
if it should have been len+RTP_HEVC_HEADERS_SIZE aka len+3).

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

1 files changed, 207 insertions, 0 deletions

diff --git a/libavformat/rtpenc_h264_hevc.c b/libavformat/rtpenc_h264_hevc.c
new file mode 100644
index 0000000000..9cfe0e2c64
--- /dev/null
+++ b/libavformat/rtpenc_h264_hevc.c
@@ -0,0 +1,207 @@
+/*
+ * RTP packetization for H.264 (RFC3984)
+ * RTP packetizer for HEVC/H.265 payload format (draft version 6)
+ * Copyright (c) 2008 Luca Abeni
+ * Copyright (c) 2014 Thomas Volkert <thomas@homer-conferencing.com>
+ *
+ * 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
+ */
+
+/**
+ * @file
+ * @brief H.264/HEVC packetization
+ * @author Luca Abeni <lucabe72@email.it>
+ */
+
+#include "libavutil/intreadwrite.h"
+
+#include "avformat.h"
+#include "avc.h"
+#include "rtpenc.h"
+
+static void flush_buffered(AVFormatContext *s1, int last)
+{
+    RTPMuxContext *s = s1->priv_data;
+    if (s->buf_ptr != s->buf) {
+        // If we're only sending one single NAL unit, send it as such, skip
+        // the STAP-A/AP framing
+        if (s->buffered_nals == 1) {
+            enum AVCodecID codec = s1->streams[0]->codec->codec_id;
+            if (codec == AV_CODEC_ID_H264)
+                ff_rtp_send_data(s1, s->buf + 3, s->buf_ptr - s->buf - 3, last);
+            else
+                ff_rtp_send_data(s1, s->buf + 4, s->buf_ptr - s->buf - 4, last);
+        } else
+            ff_rtp_send_data(s1, s->buf, s->buf_ptr - s->buf, last);
+    }
+    s->buf_ptr = s->buf;
+    s->buffered_nals = 0;
+}
+
+static void nal_send(AVFormatContext *s1, const uint8_t *buf, int size, int last)
+{
+    RTPMuxContext *s = s1->priv_data;
+    enum AVCodecID codec = s1->streams[0]->codec->codec_id;
+
+    av_log(s1, AV_LOG_DEBUG, "Sending NAL %x of len %d M=%d\n", buf[0] & 0x1F, size, last);
+    if (size <= s->max_payload_size) {
+        int buffered_size = s->buf_ptr - s->buf;
+        int header_size;
+        int skip_aggregate = 0;
+
+        if (codec == AV_CODEC_ID_H264) {
+            header_size = 1;
+            skip_aggregate = s->flags & FF_RTP_FLAG_H264_MODE0;
+        } else {
+            header_size = 2;
+        }
+
+        // Flush buffered NAL units if the current unit doesn't fit
+        if (buffered_size + 2 + size > s->max_payload_size) {
+            flush_buffered(s1, 0);
+            buffered_size = 0;
+        }
+        // If we aren't using mode 0, and the NAL unit fits including the
+        // framing (2 bytes length, plus 1/2 bytes for the STAP-A/AP marker),
+        // write the unit to the buffer as a STAP-A/AP packet, otherwise flush
+        // and send as single NAL.
+        if (buffered_size + 2 + header_size + size <= s->max_payload_size &&
+            !skip_aggregate) {
+            if (buffered_size == 0) {
+                if (codec == AV_CODEC_ID_H264) {
+                    *s->buf_ptr++ = 24;
+                } else {
+                    *s->buf_ptr++ = 48 << 1;
+                    *s->buf_ptr++ = 1;
+                }
+            }
+            AV_WB16(s->buf_ptr, size);
+            s->buf_ptr += 2;
+            memcpy(s->buf_ptr, buf, size);
+            s->buf_ptr += size;
+            s->buffered_nals++;
+        } else {
+            flush_buffered(s1, 0);
+            ff_rtp_send_data(s1, buf, size, last);
+        }
+    } else {
+        int flag_byte, header_size;
+        flush_buffered(s1, 0);
+        if (codec == AV_CODEC_ID_H264 && (s->flags & FF_RTP_FLAG_H264_MODE0)) {
+            av_log(s1, AV_LOG_ERROR,
+                   "NAL size %d > %d, try -slice-max-size %d\n", size,
+                   s->max_payload_size, s->max_payload_size);
+            return;
+        }
+        av_log(s1, AV_LOG_DEBUG, "NAL size %d > %d\n", size, s->max_payload_size);
+        if (codec == AV_CODEC_ID_H264) {
+            uint8_t type = buf[0] & 0x1F;
+            uint8_t nri = buf[0] & 0x60;
+
+            s->buf[0] = 28;        /* FU Indicator; Type = 28 ---> FU-A */
+            s->buf[0] |= nri;
+            s->buf[1] = type;
+            s->buf[1] |= 1 << 7;
+            buf  += 1;
+            size -= 1;
+
+            flag_byte   = 1;
+            header_size = 2;
+        } else {
+            uint8_t nal_type = (buf[0] >> 1) & 0x3F;
+            /*
+             * create the HEVC payload header and transmit the buffer as fragmentation units (FU)
+             *
+             *    0                   1
+             *    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+             *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+             *   |F|   Type    |  LayerId  | TID |
+             *   +-------------+-----------------+
+             *
+             *      F       = 0
+             *      Type    = 49 (fragmentation unit (FU))
+             *      LayerId = 0
+             *      TID     = 1
+             */
+            s->buf[0] = 49 << 1;
+            s->buf[1] = 1;
+
+            /*
+             *     create the FU header
+             *
+             *     0 1 2 3 4 5 6 7
+             *    +-+-+-+-+-+-+-+-+
+             *    |S|E|  FuType   |
+             *    +---------------+
+             *
+             *       S       = variable
+             *       E       = variable
+             *       FuType  = NAL unit type
+             */
+            s->buf[2]  = nal_type;
+            /* set the S bit: mark as start fragment */
+            s->buf[2] |= 1 << 7;
+
+            /* pass the original NAL header */
+            buf  += 2;
+            size -= 2;
+
+            flag_byte   = 2;
+            header_size = 3;
+        }
+
+        while (size + header_size > s->max_payload_size) {
+            memcpy(&s->buf[header_size], buf, s->max_payload_size - header_size);
+            ff_rtp_send_data(s1, s->buf, s->max_payload_size, 0);
+            buf  += s->max_payload_size - header_size;
+            size -= s->max_payload_size - header_size;
+            s->buf[flag_byte] &= ~(1 << 7);
+        }
+        s->buf[flag_byte] |= 1 << 6;
+        memcpy(&s->buf[header_size], buf, size);
+        ff_rtp_send_data(s1, s->buf, size + header_size, last);
+    }
+}
+
+void ff_rtp_send_h264_hevc(AVFormatContext *s1, const uint8_t *buf1, int size)
+{
+    const uint8_t *r, *end = buf1 + size;
+    RTPMuxContext *s = s1->priv_data;
+
+    s->timestamp = s->cur_timestamp;
+    s->buf_ptr   = s->buf;
+    if (s->nal_length_size)
+        r = ff_avc_mp4_find_startcode(buf1, end, s->nal_length_size) ? buf1 : end;
+    else
+        r = ff_avc_find_startcode(buf1, end);
+    while (r < end) {
+        const uint8_t *r1;
+
+        if (s->nal_length_size) {
+            r1 = ff_avc_mp4_find_startcode(r, end, s->nal_length_size);
+            if (!r1)
+                r1 = end;
+            r += s->nal_length_size;
+        } else {
+            while (!*(r++));
+            r1 = ff_avc_find_startcode(r, end);
+        }
+        nal_send(s1, r, r1 - r, r1 == end);
+        r = r1;
+    }
+    flush_buffered(s1, 1);
+}