rtp: rfc4175: add handler for YCbCr-4:2:2

This adds partial support for the RFC 4175 (raw video over RTP). The
only supported formats are the YCbCr-4:2:2 8 bit because it's natively
supported by FFmpeg with pixel format UYVY, and 10 bit which requires
the vrawdepay codec to convert the payload in a format handled by
FFmpeg.
Signed-off-by: Damien Riegel <damien.riegel@savoirfairelinux.com>
Reviewed-by: Rostislav Pehlivanov <atomnuker@gmail.com>

libavformat/Makefile

@@ -55,6 +55,7 @@ OBJS-$(CONFIG_RTPDEC)                    += rdt.o                       \
                                             rtpdec_qcelp.o              \
                                             rtpdec_qdm2.o               \
                                             rtpdec_qt.o                 \
+                                            rtpdec_rfc4175.o            \
                                             rtpdec_svq3.o               \
                                             rtpdec_vc2hq.o              \
                                             rtpdec_vp8.o                \

libavformat/rtpdec.c

@@ -114,6 +114,7 @@ void ff_register_rtp_dynamic_payload_handlers(void)
     ff_register_dynamic_payload_handler(&ff_qt_rtp_vid_handler);
     ff_register_dynamic_payload_handler(&ff_quicktime_rtp_aud_handler);
     ff_register_dynamic_payload_handler(&ff_quicktime_rtp_vid_handler);
+    ff_register_dynamic_payload_handler(&ff_rfc4175_rtp_handler);
     ff_register_dynamic_payload_handler(&ff_svq3_dynamic_handler);
     ff_register_dynamic_payload_handler(&ff_theora_dynamic_handler);
     ff_register_dynamic_payload_handler(&ff_vc2hq_dynamic_handler);

libavformat/rtpdec_formats.h

@@ -82,6 +82,7 @@ extern RTPDynamicProtocolHandler ff_qt_rtp_aud_handler;
 extern RTPDynamicProtocolHandler ff_qt_rtp_vid_handler;
 extern RTPDynamicProtocolHandler ff_quicktime_rtp_aud_handler;
 extern RTPDynamicProtocolHandler ff_quicktime_rtp_vid_handler;
+extern RTPDynamicProtocolHandler ff_rfc4175_rtp_handler;
 extern RTPDynamicProtocolHandler ff_svq3_dynamic_handler;
 extern RTPDynamicProtocolHandler ff_theora_dynamic_handler;
 extern RTPDynamicProtocolHandler ff_vc2hq_dynamic_handler;

libavformat/rtpdec_rfc4175.c

+/*
+ * RTP Depacketization of RAW video (TR-03)
+ * Copyright (c) 2016 Savoir-faire Linux, Inc
+ *
+ * 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
+ */
+
+/* Development sponsored by CBC/Radio-Canada */
+
+#include "avio_internal.h"
+#include "rtpdec_formats.h"
+#include "libavutil/avstring.h"
+#include "libavutil/pixdesc.h"
+
+struct PayloadContext {
+    char *sampling;
+    int depth;
+    int width;
+    int height;
+
+    uint8_t *frame;
+    unsigned int frame_size;
+    unsigned int pgroup; /* size of the pixel group in bytes */
+    unsigned int xinc;
+
+    uint32_t timestamp;
+};
+
+static int rfc4175_parse_format(AVStream *stream, PayloadContext *data)
+{
+    enum AVPixelFormat pixfmt = AV_PIX_FMT_NONE;
+    int bits_per_sample = 0;
+    int tag = 0;
+
+    if (!strncmp(data->sampling, "YCbCr-4:2:2", 11)) {
+        tag = MKTAG('U', 'Y', 'V', 'Y');
+        data->xinc = 2;
+
+        if (data->depth == 8) {
+            data->pgroup = 4;
+            bits_per_sample = 16;
+            pixfmt = AV_PIX_FMT_UYVY422;
+        } else if (data->depth == 10) {
+            data->pgroup = 5;
+            bits_per_sample = 20;
+            pixfmt = AV_PIX_FMT_YUV422P10;
+        } else {
+            return AVERROR_INVALIDDATA;
+        }
+    } else {
+        return AVERROR_INVALIDDATA;
+    }
+
+    stream->codecpar->format = pixfmt;
+    stream->codecpar->codec_tag = tag;
+    stream->codecpar->bits_per_coded_sample = bits_per_sample;
+    data->frame_size = data->width * data->height * data->pgroup / data->xinc;
+
+    return 0;
+}
+
+static int rfc4175_parse_fmtp(AVFormatContext *s, AVStream *stream,
+                              PayloadContext *data, const char *attr,
+                              const char *value)
+{
+    if (!strncmp(attr, "width", 5))
+        data->width = atoi(value);
+    else if (!strncmp(attr, "height", 6))
+        data->height = atoi(value);
+    else if (!strncmp(attr, "sampling", 8))
+        data->sampling = av_strdup(value);
+    else if (!strncmp(attr, "depth", 5))
+        data->depth = atoi(value);
+
+    return 0;
+}
+
+static int rfc4175_parse_sdp_line(AVFormatContext *s, int st_index,
+                                  PayloadContext *data, const char *line)
+{
+    const char *p;
+
+    if (st_index < 0)
+        return 0;
+
+    if (av_strstart(line, "fmtp:", &p)) {
+        AVStream *stream = s->streams[st_index];
+        int ret = ff_parse_fmtp(s, stream, data, p, rfc4175_parse_fmtp);
+
+        if (ret < 0)
+            return ret;
+
+
+        if (!data->sampling || !data->depth || !data->width || !data->height)
+            return -1;
+
+        stream->codecpar->width = data->width;
+        stream->codecpar->height = data->height;
+
+        ret = rfc4175_parse_format(stream, data);
+        av_freep(&data->sampling);
+
+        return ret;
+    }
+
+    return 0;
+}
+
+static int rfc4175_finalize_packet(PayloadContext *data, AVPacket *pkt,
+                                   int stream_index)
+{
+   int ret;
+
+   pkt->stream_index = stream_index;
+   ret = av_packet_from_data(pkt, data->frame, data->frame_size);
+   if (ret < 0) {
+       av_freep(&data->frame);
+   }
+
+   data->frame = NULL;
+
+   return ret;
+}
+
+static int rfc4175_handle_packet(AVFormatContext *ctx, PayloadContext *data,
+                                 AVStream *st, AVPacket *pkt, uint32_t *timestamp,
+                                 const uint8_t * buf, int len,
+                                 uint16_t seq, int flags)
+{
+    int length, line, offset, cont;
+    const uint8_t *headers = buf + 2; /* skip extended seqnum */
+    const uint8_t *payload = buf + 2;
+    int payload_len = len - 2;
+    int missed_last_packet = 0;
+
+    uint8_t *dest;
+
+    if (*timestamp != data->timestamp) {
+        if (data->frame) {
+            /*
+             * if we're here, it means that two RTP packets didn't have the
+             * same timestamp, which is a sign that they were packets from two
+             * different frames, but we didn't get the flag RTP_FLAG_MARKER on
+             * the first one of these frames (last packet of a frame).
+             * Finalize the previous frame anyway by filling the AVPacket.
+             */
+            av_log(ctx, AV_LOG_ERROR, "Missed previous RTP Marker\n");
+            missed_last_packet = 1;
+            rfc4175_finalize_packet(data, pkt, st->index);
+        }
+
+        data->frame = av_malloc(data->frame_size);
+
+        data->timestamp = *timestamp;
+
+        if (!data->frame) {
+            av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
+            return AVERROR(ENOMEM);
+        }
+    }
+
+    /*
+     * looks for the 'Continuation bit' in scan lines' headers
+     * to find where data start
+     */
+    do {
+        if (payload_len < 6)
+            return AVERROR_INVALIDDATA;
+
+        cont = payload[4] & 0x80;
+        payload += 6;
+        payload_len -= 6;
+    } while (cont);
+
+    /* and now iterate over every scan lines */
+    do {
+        int copy_offset;
+
+        if (payload_len < data->pgroup)
+            return AVERROR_INVALIDDATA;
+
+        length = (headers[0] << 8) | headers[1];
+        line = ((headers[2] & 0x7f) << 8) | headers[3];
+        offset = ((headers[4] & 0x7f) << 8) | headers[5];
+        cont = headers[4] & 0x80;
+        headers += 6;
+
+        if (length % data->pgroup)
+            return AVERROR_INVALIDDATA;
+
+        if (length > payload_len)
+            length = payload_len;
+
+        /* prevent ill-formed packets to write after buffer's end */
+        copy_offset = (line * data->width + offset) * data->pgroup / data->xinc;
+        if (copy_offset + length > data->frame_size)
+            return AVERROR_INVALIDDATA;
+
+        dest = data->frame + copy_offset;
+        memcpy(dest, payload, length);
+
+        payload += length;
+        payload_len -= length;
+    } while (cont);
+
+    if ((flags & RTP_FLAG_MARKER)) {
+        return rfc4175_finalize_packet(data, pkt, st->index);
+    } else if (missed_last_packet) {
+        return 0;
+    }
+
+    return AVERROR(EAGAIN);
+}
+
+RTPDynamicProtocolHandler ff_rfc4175_rtp_handler = {
+    .enc_name           = "raw",
+    .codec_type         = AVMEDIA_TYPE_VIDEO,
+    .codec_id           = AV_CODEC_ID_BITPACKED,
+    .priv_data_size     = sizeof(PayloadContext),
+    .parse_sdp_a_line   = rfc4175_parse_sdp_line,
+    .parse_packet       = rfc4175_handle_packet,
+};