[FFmpeg-cvslog] rtp: Initial H.261 support
Thomas Volkert
git at videolan.org
Fri Dec 19 02:48:15 CET 2014
ffmpeg | branch: master | Thomas Volkert <thomas at homer-conferencing.com> | Sat Dec 6 19:54:07 2014 +0100| [a505c0d7373336a4cc5aa2022111c46bdd388b1f] | committer: Martin Storsjö
rtp: Initial H.261 support
The packetizer only supports splitting at GOB headers - if
such aren't available frequently enough, it splits at any
random byte offset (not at a macroblock boundary either, which
would be allowed by the spec) and sends a payload header pretend
that it starts with a GOB header.
As long as a receiver doesn't try to handle such cases cleverly
but just drops broken frames, this shouldn't matter too much
in practice.
Signed-off-by: Martin Storsjö <martin at martin.st>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=a505c0d7373336a4cc5aa2022111c46bdd388b1f
---
Changelog | 1 +
libavformat/Makefile | 2 +
libavformat/rtpdec.c | 1 +
libavformat/rtpdec_formats.h | 1 +
libavformat/rtpdec_h261.c | 202 ++++++++++++++++++++++++++++++++++++++++++
libavformat/rtpenc.c | 19 +++-
libavformat/rtpenc.h | 1 +
libavformat/rtpenc_h261.c | 102 +++++++++++++++++++++
libavformat/sdp.c | 14 +++
libavformat/version.h | 4 +-
10 files changed, 343 insertions(+), 4 deletions(-)
diff --git a/Changelog b/Changelog
index 6af2e8a..85fb678 100644
--- a/Changelog
+++ b/Changelog
@@ -7,6 +7,7 @@ version <next>:
- avplay now exits by default at the end of playback
- XCB-based screen-grabber
- creating DASH compatible fragmented MP4, MPEG-DASH segmenting muxer
+- H.261 RTP payload format (RFC 4587) depacketizer and experimental packetizer
version 11:
diff --git a/libavformat/Makefile b/libavformat/Makefile
index 035eb72..affb95a 100644
--- a/libavformat/Makefile
+++ b/libavformat/Makefile
@@ -32,6 +32,7 @@ OBJS-$(CONFIG_RTPDEC) += rdt.o \
rtpdec_amr.o \
rtpdec_asf.o \
rtpdec_g726.o \
+ rtpdec_h261.o \
rtpdec_h263.o \
rtpdec_h263_rfc2190.o \
rtpdec_h264.o \
@@ -290,6 +291,7 @@ OBJS-$(CONFIG_RTP_MUXER) += rtp.o \
rtpenc_aac.o \
rtpenc_latm.o \
rtpenc_amr.o \
+ rtpenc_h261.o \
rtpenc_h263.o \
rtpenc_h263_rfc2190.o \
rtpenc_hevc.o \
diff --git a/libavformat/rtpdec.c b/libavformat/rtpdec.c
index b5e5200..97f1428 100644
--- a/libavformat/rtpdec.c
+++ b/libavformat/rtpdec.c
@@ -66,6 +66,7 @@ void ff_register_rtp_dynamic_payload_handlers(void)
ff_register_dynamic_payload_handler(&ff_g726_24_dynamic_handler);
ff_register_dynamic_payload_handler(&ff_g726_32_dynamic_handler);
ff_register_dynamic_payload_handler(&ff_g726_40_dynamic_handler);
+ ff_register_dynamic_payload_handler(&ff_h261_dynamic_handler);
ff_register_dynamic_payload_handler(&ff_h263_1998_dynamic_handler);
ff_register_dynamic_payload_handler(&ff_h263_2000_dynamic_handler);
ff_register_dynamic_payload_handler(&ff_h263_rfc2190_dynamic_handler);
diff --git a/libavformat/rtpdec_formats.h b/libavformat/rtpdec_formats.h
index 02335ed..0c9f49c 100644
--- a/libavformat/rtpdec_formats.h
+++ b/libavformat/rtpdec_formats.h
@@ -41,6 +41,7 @@ extern RTPDynamicProtocolHandler ff_g726_16_dynamic_handler;
extern RTPDynamicProtocolHandler ff_g726_24_dynamic_handler;
extern RTPDynamicProtocolHandler ff_g726_32_dynamic_handler;
extern RTPDynamicProtocolHandler ff_g726_40_dynamic_handler;
+extern RTPDynamicProtocolHandler ff_h261_dynamic_handler;
extern RTPDynamicProtocolHandler ff_h263_1998_dynamic_handler;
extern RTPDynamicProtocolHandler ff_h263_2000_dynamic_handler;
extern RTPDynamicProtocolHandler ff_h263_rfc2190_dynamic_handler;
diff --git a/libavformat/rtpdec_h261.c b/libavformat/rtpdec_h261.c
new file mode 100644
index 0000000..4988300
--- /dev/null
+++ b/libavformat/rtpdec_h261.c
@@ -0,0 +1,202 @@
+/*
+ * RTP parser for H.261 payload format (RFC 4587)
+ * Copyright (c) 2014 Thomas Volkert <thomas at 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
+ */
+
+#include "libavcodec/get_bits.h"
+#include "avformat.h"
+#include "rtpdec_formats.h"
+
+#define RTP_H261_PAYLOAD_HEADER_SIZE 4
+
+struct PayloadContext {
+ AVIOContext *buf;
+ uint8_t endbyte;
+ int endbyte_bits;
+ uint32_t timestamp;
+};
+
+static av_cold PayloadContext *h261_new_context(void)
+{
+ return av_mallocz(sizeof(PayloadContext));
+}
+
+static void h261_free_dyn_buffer(AVIOContext **dyn_buf)
+{
+ uint8_t *ptr_dyn_buffer;
+ avio_close_dyn_buf(*dyn_buf, &ptr_dyn_buffer);
+ av_free(ptr_dyn_buffer);
+ *dyn_buf = NULL;
+}
+
+static av_cold void h261_free_context(PayloadContext *pl_ctx)
+{
+ /* return if context is invalid */
+ if (!pl_ctx)
+ return;
+
+ /* free buffer if it is valid */
+ if (pl_ctx->buf) {
+ h261_free_dyn_buffer(&pl_ctx->buf);
+ }
+
+ /* free context */
+ av_free(pl_ctx);
+}
+
+static av_cold int h261_init(AVFormatContext *ctx, int st_index,
+ PayloadContext *data)
+{
+ if (st_index < 0)
+ return 0;
+
+ ctx->streams[st_index]->need_parsing = AVSTREAM_PARSE_FULL;
+
+ return 0;
+}
+
+static int h261_handle_packet(AVFormatContext *ctx, PayloadContext *rtp_h261_ctx,
+ AVStream *st, AVPacket *pkt, uint32_t *timestamp,
+ const uint8_t *buf, int len, uint16_t seq,
+ int flags)
+{
+ int sbit, ebit, gobn, mbap, quant;
+ int res;
+
+ /* drop data of previous packets in case of non-continuous (lossy) packet stream */
+ if (rtp_h261_ctx->buf && rtp_h261_ctx->timestamp != *timestamp) {
+ h261_free_dyn_buffer(&rtp_h261_ctx->buf);
+ rtp_h261_ctx->endbyte_bits = 0;
+ }
+
+ /* sanity check for size of input packet: 1 byte payload at least */
+ if (len < RTP_H261_PAYLOAD_HEADER_SIZE + 1) {
+ av_log(ctx, AV_LOG_ERROR, "Too short RTP/H.261 packet, got %d bytes\n", len);
+ return AVERROR_INVALIDDATA;
+ }
+
+ /*
+ * decode the H.261 payload header according to section 4.1 of RFC 4587:
+ * (uses 4 bytes between RTP header and H.261 stream per packet)
+ *
+ * 0 1 2 3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |SBIT |EBIT |I|V| GOBN | MBAP | QUANT | HMVD | VMVD |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *
+ * Start bit position (SBIT): 3 bits
+ * End bit position (EBIT): 3 bits
+ * INTRA-frame encoded data (I): 1 bit
+ * Motion Vector flag (V): 1 bit
+ * GOB number (GOBN): 4 bits
+ * Macroblock address predictor (MBAP): 5 bits
+ * Quantizer (QUANT): 5 bits
+ * Horizontal motion vector data (HMVD): 5 bits
+ * Vertical motion vector data (VMVD): 5 bits
+ */
+ sbit = (buf[0] >> 5) & 0x07;
+ ebit = (buf[0] >> 2) & 0x07;
+ gobn = (buf[1] >> 4) & 0x0f;
+ mbap = ((buf[1] << 1) & 0x1e) | ((buf[2] >> 7) & 0x01);
+ quant = (buf[2] >> 2) & 0x1f;
+
+ /* pass the H.261 payload header and continue with the actual payload */
+ buf += RTP_H261_PAYLOAD_HEADER_SIZE;
+ len -= RTP_H261_PAYLOAD_HEADER_SIZE;
+
+ /* start frame buffering with new dynamic buffer */
+ if (!rtp_h261_ctx->buf) {
+ /* sanity check: a new frame starts with gobn=0, sbit=0, mbap=0, quant=0 */
+ if (!gobn && !sbit && !mbap && !quant) {
+ res = avio_open_dyn_buf(&rtp_h261_ctx->buf);
+ if (res < 0)
+ return res;
+ /* update the timestamp in the frame packet with the one from the RTP packet */
+ rtp_h261_ctx->timestamp = *timestamp;
+ } else {
+ /* frame not started yet, need more packets */
+ return AVERROR(EAGAIN);
+ }
+ }
+
+ /* do the "byte merging" at the boundaries of two consecutive frame fragments */
+ if (rtp_h261_ctx->endbyte_bits || sbit) {
+ if (rtp_h261_ctx->endbyte_bits == sbit) {
+ rtp_h261_ctx->endbyte |= buf[0] & (0xff >> sbit);
+ rtp_h261_ctx->endbyte_bits = 0;
+ buf++;
+ len--;
+ avio_w8(rtp_h261_ctx->buf, rtp_h261_ctx->endbyte);
+ } else {
+ /* ebit/sbit values inconsistent, assuming packet loss */
+ GetBitContext gb;
+ init_get_bits(&gb, buf, len*8 - ebit);
+ skip_bits(&gb, sbit);
+ if (rtp_h261_ctx->endbyte_bits) {
+ rtp_h261_ctx->endbyte |= get_bits(&gb, 8 - rtp_h261_ctx->endbyte_bits);
+ avio_w8(rtp_h261_ctx->buf, rtp_h261_ctx->endbyte);
+ }
+ while (get_bits_left(&gb) >= 8)
+ avio_w8(rtp_h261_ctx->buf, get_bits(&gb, 8));
+ rtp_h261_ctx->endbyte_bits = get_bits_left(&gb);
+ if (rtp_h261_ctx->endbyte_bits)
+ rtp_h261_ctx->endbyte = get_bits(&gb, rtp_h261_ctx->endbyte_bits) <<
+ (8 - rtp_h261_ctx->endbyte_bits);
+ ebit = 0;
+ len = 0;
+ }
+ }
+ if (ebit) {
+ if (len > 0)
+ avio_write(rtp_h261_ctx->buf, buf, len - 1);
+ rtp_h261_ctx->endbyte_bits = 8 - ebit;
+ rtp_h261_ctx->endbyte = buf[len - 1] & (0xff << ebit);
+ } else {
+ avio_write(rtp_h261_ctx->buf, buf, len);
+ }
+
+ /* RTP marker bit means: last fragment of current frame was received;
+ otherwise, an additional fragment is needed for the current frame */
+ if (!(flags & RTP_FLAG_MARKER))
+ return AVERROR(EAGAIN);
+
+ /* write the completed last byte from the "byte merging" */
+ if (rtp_h261_ctx->endbyte_bits)
+ avio_w8(rtp_h261_ctx->buf, rtp_h261_ctx->endbyte);
+ rtp_h261_ctx->endbyte_bits = 0;
+
+ /* close frame buffering and create resulting A/V packet */
+ res = ff_rtp_finalize_packet(pkt, &rtp_h261_ctx->buf, st->index);
+ if (res < 0)
+ return res;
+
+ return 0;
+}
+
+RTPDynamicProtocolHandler ff_h261_dynamic_handler = {
+ .enc_name = "H261",
+ .codec_type = AVMEDIA_TYPE_VIDEO,
+ .codec_id = AV_CODEC_ID_H261,
+ .init = h261_init,
+ .alloc = h261_new_context,
+ .free = h261_free_context,
+ .parse_packet = h261_handle_packet,
+ .static_payload_id = 31,
+};
diff --git a/libavformat/rtpenc.c b/libavformat/rtpenc.c
index e5dc805..bf82da0 100644
--- a/libavformat/rtpenc.c
+++ b/libavformat/rtpenc.c
@@ -49,6 +49,7 @@ static const AVClass rtp_muxer_class = {
static int is_supported(enum AVCodecID id)
{
switch(id) {
+ case AV_CODEC_ID_H261:
case AV_CODEC_ID_H263:
case AV_CODEC_ID_H263P:
case AV_CODEC_ID_H264:
@@ -88,7 +89,7 @@ static int is_supported(enum AVCodecID id)
static int rtp_write_header(AVFormatContext *s1)
{
RTPMuxContext *s = s1->priv_data;
- int n;
+ int n, ret = AVERROR(EINVAL);
AVStream *st;
if (s1->nb_streams != 1) {
@@ -191,6 +192,17 @@ static int rtp_write_header(AVFormatContext *s1)
s->max_payload_size = n * TS_PACKET_SIZE;
s->buf_ptr = s->buf;
break;
+ case AV_CODEC_ID_H261:
+ if (s1->strict_std_compliance > FF_COMPLIANCE_EXPERIMENTAL) {
+ av_log(s, AV_LOG_ERROR,
+ "Packetizing H261 is experimental and produces incorrect "
+ "packetization for cases where GOBs don't fit into packets "
+ "(even though most receivers may handle it just fine). "
+ "Please set -f_strict experimental in order to enable it.\n");
+ ret = AVERROR_EXPERIMENTAL;
+ goto fail;
+ }
+ break;
case AV_CODEC_ID_H264:
/* check for H.264 MP4 syntax */
if (st->codec->extradata_size > 4 && st->codec->extradata[0] == 1) {
@@ -273,7 +285,7 @@ defaultcase:
fail:
av_freep(&s->buf);
- return AVERROR(EINVAL);
+ return ret;
}
/* send an rtcp sender report packet */
@@ -567,6 +579,9 @@ static int rtp_write_packet(AVFormatContext *s1, AVPacket *pkt)
case AV_CODEC_ID_H264:
ff_rtp_send_h264(s1, pkt->data, size);
break;
+ case AV_CODEC_ID_H261:
+ ff_rtp_send_h261(s1, pkt->data, size);
+ break;
case AV_CODEC_ID_H263:
if (s->flags & FF_RTP_FLAG_RFC2190) {
int mb_info_size = 0;
diff --git a/libavformat/rtpenc.h b/libavformat/rtpenc.h
index 4a72a49..f2ac0fa 100644
--- a/libavformat/rtpenc.h
+++ b/libavformat/rtpenc.h
@@ -81,6 +81,7 @@ typedef struct RTPMuxContext RTPMuxContext;
void ff_rtp_send_data(AVFormatContext *s1, const uint8_t *buf1, int len, int m);
void ff_rtp_send_h264(AVFormatContext *s1, const uint8_t *buf1, int size);
+void ff_rtp_send_h261(AVFormatContext *s1, const uint8_t *buf1, int size);
void ff_rtp_send_h263(AVFormatContext *s1, const uint8_t *buf1, int size);
void ff_rtp_send_h263_rfc2190(AVFormatContext *s1, const uint8_t *buf1, int size,
const uint8_t *mb_info, int mb_info_size);
diff --git a/libavformat/rtpenc_h261.c b/libavformat/rtpenc_h261.c
new file mode 100644
index 0000000..514e7bf
--- /dev/null
+++ b/libavformat/rtpenc_h261.c
@@ -0,0 +1,102 @@
+/*
+ * RTP packetization for H.261 video (RFC 4587)
+ * Copyright (c) 2014 Thomas Volkert <thomas at 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
+ */
+
+#include "avformat.h"
+#include "rtpenc.h"
+
+#define RTP_H261_HEADER_SIZE 4
+
+static const uint8_t *find_resync_marker_reverse(const uint8_t *restrict start,
+ const uint8_t *restrict end)
+{
+ const uint8_t *p = end - 1;
+ start += 1; /* Make sure we never return the original start. */
+ for (; p > start; p--) {
+ if (p[0] == 0 && p[1] == 1)
+ return p;
+ }
+ return end;
+}
+
+void ff_rtp_send_h261(AVFormatContext *ctx, const uint8_t *frame_buf, int frame_size)
+{
+ int cur_frame_size;
+ int last_packet_of_frame;
+ RTPMuxContext *rtp_ctx = ctx->priv_data;
+
+ /* use the default 90 KHz time stamp */
+ rtp_ctx->timestamp = rtp_ctx->cur_timestamp;
+
+ /* continue as long as not all frame data is processed */
+ while (frame_size > 0) {
+ /*
+ * encode the H.261 payload header according to section 4.1 of RFC 4587:
+ * (uses 4 bytes between RTP header and H.261 stream per packet)
+ *
+ * 0 1 2 3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |SBIT |EBIT |I|V| GOBN | MBAP | QUANT | HMVD | VMVD |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *
+ * Start bit position (SBIT): 3 bits
+ * End bit position (EBIT): 3 bits
+ * INTRA-frame encoded data (I): 1 bit
+ * Motion Vector flag (V): 1 bit
+ * GOB number (GOBN): 4 bits
+ * Macroblock address predictor (MBAP): 5 bits
+ * Quantizer (QUANT): 5 bits
+ * Horizontal motion vector data (HMVD): 5 bits
+ * Vertical motion vector data (VMVD): 5 bits
+ */
+ rtp_ctx->buf[0] = 1; /* sbit=0, ebit=0, i=0, v=1 */
+ rtp_ctx->buf[1] = 0; /* gobn=0, mbap=0 */
+ rtp_ctx->buf[2] = 0; /* quant=0, hmvd=5 */
+ rtp_ctx->buf[3] = 0; /* vmvd=0 */
+ if (frame_size < 2 || frame_buf[0] != 0 || frame_buf[1] != 1) {
+ /* A full, correct fix for this would be to make the H261 encoder
+ * support inserting extra GOB headers (triggered by setting e.g.
+ * "-ps 1"), and including information about macroblock boundaries
+ * (such as for h263_rfc2190). */
+ av_log(ctx, AV_LOG_WARNING,
+ "RTP/H261 packet not cut at a GOB boundary, not signaled correctly\n");
+ }
+
+ cur_frame_size = FFMIN(rtp_ctx->max_payload_size - RTP_H261_HEADER_SIZE, frame_size);
+
+ /* look for a better place to split the frame into packets */
+ if (cur_frame_size < frame_size) {
+ const uint8_t *packet_end = find_resync_marker_reverse(frame_buf,
+ frame_buf + cur_frame_size);
+ cur_frame_size = packet_end - frame_buf;
+ }
+
+ /* calculate the "marker" bit for the RTP header */
+ last_packet_of_frame = cur_frame_size == frame_size;
+
+ /* complete and send RTP packet */
+ memcpy(&rtp_ctx->buf[RTP_H261_HEADER_SIZE], frame_buf, cur_frame_size);
+ ff_rtp_send_data(ctx, rtp_ctx->buf, RTP_H261_HEADER_SIZE + cur_frame_size, last_packet_of_frame);
+
+ frame_buf += cur_frame_size;
+ frame_size -= cur_frame_size;
+ }
+}
diff --git a/libavformat/sdp.c b/libavformat/sdp.c
index a14a239..fe43e04 100644
--- a/libavformat/sdp.c
+++ b/libavformat/sdp.c
@@ -498,6 +498,20 @@ static char *sdp_write_media_attributes(char *buff, int size, AVCodecContext *c,
payload_type, mode, config ? config : "");
break;
}
+ case AV_CODEC_ID_H261:
+ {
+ const char *pic_fmt = NULL;
+ /* only QCIF and CIF are specified as supported in RFC 4587 */
+ if (c->width == 176 && c->height == 144)
+ pic_fmt = "QCIF=1";
+ else if (c->width == 352 && c->height == 288)
+ pic_fmt = "CIF=1";
+ if (payload_type >= RTP_PT_PRIVATE)
+ av_strlcatf(buff, size, "a=rtpmap:%d H261/90000\r\n", payload_type);
+ if (pic_fmt)
+ av_strlcatf(buff, size, "a=fmtp:%d %s\r\n", payload_type, pic_fmt);
+ break;
+ }
case AV_CODEC_ID_H263:
case AV_CODEC_ID_H263P:
/* a=framesize is required by 3GPP TS 26.234 (PSS). It
diff --git a/libavformat/version.h b/libavformat/version.h
index 16c5e2e..b2f5327 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 7
-#define LIBAVFORMAT_VERSION_MICRO 2
+#define LIBAVFORMAT_VERSION_MINOR 8
+#define LIBAVFORMAT_VERSION_MICRO 0
#define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
LIBAVFORMAT_VERSION_MINOR, \
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