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FFmpeg/libavformat/rtpdec_hevc.c
Vittorio Giovara c463dfc7e4 rtpdec_hevc: Drop a duplicated, nonstandard entry 
The RFC spec draft only specifies the "H265" name - there is no
specification saying how to interpret "HEVC" (if such a packet
format is specified it could be an entirely different format).

Since this is a very new standard (still a draft), there is little
need for compatibility with existing, broken implementations. Therefore
remove the extra alias, to avoid the risk of encouraging incorrect
usage.

Intentionally keeping the ff_hevc_dynamic_handler name for the
handler, to use "hevc" consistently as name for the codec instead
of "h265" within the library internals as long as there only is one
single variant in actual use.

Signed-off-by: Martin Storsjö <martin@martin.st>
2014-09-24 10:44:14 +03:00

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/*
* RTP parser for HEVC/H.265 payload format (draft version 6)
* 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
*
*/
#include "libavutil/avstring.h"
#include "avformat.h"
#include "rtpdec.h"
#define RTP_HEVC_PAYLOAD_HEADER_SIZE 2
#define RTP_HEVC_FU_HEADER_SIZE 1
#define RTP_HEVC_DONL_FIELD_SIZE 2
#define HEVC_SPECIFIED_NAL_UNIT_TYPES 48
/* SDP out-of-band signaling data */
struct PayloadContext {
int using_donl_field;
int profile_id;
};
static const uint8_t start_sequence[] = { 0x00, 0x00, 0x00, 0x01 };
static av_cold PayloadContext *hevc_new_context(void)
{
return av_mallocz(sizeof(PayloadContext));
}
static av_cold void hevc_free_context(PayloadContext *data)
{
av_free(data);
}
static av_cold int hevc_init(AVFormatContext *ctx, int st_index,
PayloadContext *data)
{
av_dlog(ctx, "hevc_init() for stream %d\n", st_index);
if (st_index < 0)
return 0;
ctx->streams[st_index]->need_parsing = AVSTREAM_PARSE_FULL;
return 0;
}
static av_cold int hevc_sdp_parse_fmtp_config(AVFormatContext *s,
AVStream *stream,
PayloadContext *hevc_data,
char *attr, char *value)
{
/* profile-space: 0-3 */
/* profile-id: 0-31 */
if (!strcmp(attr, "profile-id")) {
hevc_data->profile_id = atoi(value);
av_dlog(s, "SDP: found profile-id: %d\n", hevc_data->profile_id);
}
/* tier-flag: 0-1 */
/* level-id: 0-255 */
/* interop-constraints: [base16] */
/* profile-compatibility-indicator: [base16] */
/* sprop-sub-layer-id: 0-6, defines highest possible value for TID, default: 6 */
/* recv-sub-layer-id: 0-6 */
/* max-recv-level-id: 0-255 */
/* tx-mode: MSM,SSM */
/* sprop-vps: [base64] */
/* sprop-sps: [base64] */
/* sprop-pps: [base64] */
/* sprop-sei: [base64] */
/* max-lsr, max-lps, max-cpb, max-dpb, max-br, max-tr, max-tc */
/* max-fps */
/* sprop-max-don-diff: 0-32767
When the RTP stream depends on one or more other RTP
streams (in this case tx-mode MUST be equal to "MSM" and
MSM is in use), this parameter MUST be present and the
value MUST be greater than 0.
*/
if (!strcmp(attr, "sprop-max-don-diff")) {
if (atoi(value) > 0)
hevc_data->using_donl_field = 1;
av_dlog(s, "Found sprop-max-don-diff in SDP, DON field usage is: %d\n",
hevc_data->using_donl_field);
}
/* sprop-depack-buf-nalus: 0-32767 */
if (!strcmp(attr, "sprop-depack-buf-nalus")) {
if (atoi(value) > 0)
hevc_data->using_donl_field = 1;
av_dlog(s, "Found sprop-depack-buf-nalus in SDP, DON field usage is: %d\n",
hevc_data->using_donl_field);
}
/* sprop-depack-buf-bytes: 0-4294967295 */
/* depack-buf-cap */
/* sprop-segmentation-id: 0-3 */
/* sprop-spatial-segmentation-idc: [base16] */
/* dec-parallel-ca: */
/* include-dph */
return 0;
}
static av_cold int hevc_parse_sdp_line(AVFormatContext *ctx, int st_index,
PayloadContext *hevc_data, const char *line)
{
AVStream *current_stream;
AVCodecContext *codec;
const char *sdp_line_ptr = line;
if (st_index < 0)
return 0;
current_stream = ctx->streams[st_index];
codec = current_stream->codec;
if (av_strstart(sdp_line_ptr, "framesize:", &sdp_line_ptr)) {
char str_video_width[50];
char *str_video_width_ptr = str_video_width;
/*
* parse "a=framesize:96 320-240"
*/
/* ignore spaces */
while (*sdp_line_ptr && *sdp_line_ptr == ' ')
sdp_line_ptr++;
/* ignore RTP payload ID */
while (*sdp_line_ptr && *sdp_line_ptr != ' ')
sdp_line_ptr++;
/* ignore spaces */
while (*sdp_line_ptr && *sdp_line_ptr == ' ')
sdp_line_ptr++;
/* extract the actual video resolution description */
while (*sdp_line_ptr && *sdp_line_ptr != '-' &&
(str_video_width_ptr - str_video_width) < sizeof(str_video_width) - 1)
*str_video_width_ptr++ = *sdp_line_ptr++;
/* add trailing zero byte */
*str_video_width_ptr = '\0';
/* determine the width value */
codec->width = atoi(str_video_width);
/* jump beyond the "-" and determine the height value */
codec->height = atoi(sdp_line_ptr + 1);
} else if (av_strstart(sdp_line_ptr, "fmtp:", &sdp_line_ptr)) {
return ff_parse_fmtp(ctx, current_stream, hevc_data, sdp_line_ptr,
hevc_sdp_parse_fmtp_config);
}
return 0;
}
static int hevc_handle_packet(AVFormatContext *ctx, PayloadContext *rtp_hevc_ctx,
AVStream *st, AVPacket *pkt, uint32_t *timestamp,
const uint8_t *buf, int len, uint16_t seq,
int flags)
{
const uint8_t *rtp_pl = buf;
int tid, lid, nal_type;
int first_fragment, last_fragment, fu_type;
uint8_t new_nal_header[2];
int res = 0;
/* sanity check for size of input packet: 1 byte payload at least */
if (len < RTP_HEVC_PAYLOAD_HEADER_SIZE + 1) {
av_log(ctx, AV_LOG_ERROR, "Too short RTP/HEVC packet, got %d bytes\n", len);
return AVERROR_INVALIDDATA;
}
/*
decode the HEVC payload header according to section 4 of draft version 6:
0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|F| Type | LayerId | TID |
+-------------+-----------------+
Forbidden zero (F): 1 bit
NAL unit type (Type): 6 bits
NUH layer ID (LayerId): 6 bits
NUH temporal ID plus 1 (TID): 3 bits
*/
nal_type = (buf[0] >> 1) & 0x3f;
lid = ((buf[0] << 5) & 0x20) | ((buf[1] >> 3) & 0x1f);
tid = buf[1] & 0x07;
/* sanity check for correct layer ID */
if (lid) {
/* future scalable or 3D video coding extensions */
avpriv_report_missing_feature(ctx, "Multi-layer HEVC coding\n");
return AVERROR_PATCHWELCOME;
}
/* sanity check for correct temporal ID */
if (!tid) {
av_log(ctx, AV_LOG_ERROR, "Illegal temporal ID in RTP/HEVC packet\n");
return AVERROR_INVALIDDATA;
}
/* sanity check for correct NAL unit type */
if (nal_type > 50) {
av_log(ctx, AV_LOG_ERROR, "Unsupported (HEVC) NAL type (%d)\n", nal_type);
return AVERROR_INVALIDDATA;
}
switch (nal_type) {
/* aggregated packets (AP) */
case 48:
/* pass the HEVC payload header */
buf += RTP_HEVC_PAYLOAD_HEADER_SIZE;
len -= RTP_HEVC_PAYLOAD_HEADER_SIZE;
/* pass the HEVC DONL field */
if (rtp_hevc_ctx->using_donl_field) {
buf += RTP_HEVC_DONL_FIELD_SIZE;
len -= RTP_HEVC_DONL_FIELD_SIZE;
}
/* fall-through */
/* video parameter set (VPS) */
case 32:
/* sequence parameter set (SPS) */
case 33:
/* picture parameter set (PPS) */
case 34:
/* supplemental enhancement information (SEI) */
case 39:
/* single NAL unit packet */
default:
/* sanity check for size of input packet: 1 byte payload at least */
if (len < 1) {
av_log(ctx, AV_LOG_ERROR,
"Too short RTP/HEVC packet, got %d bytes of NAL unit type %d\n",
len, nal_type);
return AVERROR_INVALIDDATA;
}
/* create A/V packet */
if ((res = av_new_packet(pkt, sizeof(start_sequence) + len)) < 0)
return res;
/* A/V packet: copy start sequence */
memcpy(pkt->data, start_sequence, sizeof(start_sequence));
/* A/V packet: copy NAL unit data */
memcpy(pkt->data + sizeof(start_sequence), buf, len);
break;
/* fragmentation unit (FU) */
case 49:
/* pass the HEVC payload header */
buf += RTP_HEVC_PAYLOAD_HEADER_SIZE;
len -= RTP_HEVC_PAYLOAD_HEADER_SIZE;
if (len < 1)
return AVERROR_INVALIDDATA;
/*
decode the FU header
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|S|E| FuType |
+---------------+
Start fragment (S): 1 bit
End fragment (E): 1 bit
FuType: 6 bits
*/
first_fragment = buf[0] & 0x80;
last_fragment = buf[0] & 0x40;
fu_type = buf[0] & 0x3f;
/* pass the HEVC FU header */
buf += RTP_HEVC_FU_HEADER_SIZE;
len -= RTP_HEVC_FU_HEADER_SIZE;
/* pass the HEVC DONL field */
if (rtp_hevc_ctx->using_donl_field) {
buf += RTP_HEVC_DONL_FIELD_SIZE;
len -= RTP_HEVC_DONL_FIELD_SIZE;
}
av_dlog(ctx, " FU type %d with %d bytes\n", fu_type, len);
if (len > 0) {
new_nal_header[0] = (rtp_pl[0] & 0x81) | (fu_type << 1);
new_nal_header[1] = rtp_pl[1];
/* start fragment vs. subsequent fragments */
if (first_fragment) {
if (!last_fragment) {
/* create A/V packet which is big enough */
if ((res = av_new_packet(pkt, sizeof(start_sequence) + sizeof(new_nal_header) + len)) < 0)
return res;
/* A/V packet: copy start sequence */
memcpy(pkt->data, start_sequence, sizeof(start_sequence));
/* A/V packet: copy new NAL header */
memcpy(pkt->data + sizeof(start_sequence), new_nal_header, sizeof(new_nal_header));
/* A/V packet: copy NAL unit data */
memcpy(pkt->data + sizeof(start_sequence) + sizeof(new_nal_header), buf, len);
} else {
av_log(ctx, AV_LOG_ERROR, "Illegal combination of S and E bit in RTP/HEVC packet\n");
res = AVERROR_INVALIDDATA;
}
} else {
/* create A/V packet */
if ((res = av_new_packet(pkt, len)) < 0)
return res;
/* A/V packet: copy NAL unit data */
memcpy(pkt->data, buf, len);
}
} else {
/* sanity check for size of input packet: 1 byte payload at least */
av_log(ctx, AV_LOG_ERROR,
"Too short RTP/HEVC packet, got %d bytes of NAL unit type %d\n",
len, nal_type);
res = AVERROR_INVALIDDATA;
}
break;
/* PACI packet */
case 50:
/* Temporal scalability control information (TSCI) */
avpriv_report_missing_feature(ctx, "PACI packets for RTP/HEVC\n");
res = AVERROR_PATCHWELCOME;
break;
}
pkt->stream_index = st->index;
return res;
}
RTPDynamicProtocolHandler ff_hevc_dynamic_handler = {
.enc_name = "H265",
.codec_type = AVMEDIA_TYPE_VIDEO,
.codec_id = AV_CODEC_ID_HEVC,
.init = hevc_init,
.parse_sdp_a_line = hevc_parse_sdp_line,
.alloc = hevc_new_context,
.free = hevc_free_context,
.parse_packet = hevc_handle_packet
};
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