/*
* RTP VP8 Depacketizer
* Copyright (c) 2010 Josh Allmann
+ * Copyright (c) 2012 Martin Storsjo
*
- * This file is part of FFmpeg.
+ * This file is part of Libav.
*
- * FFmpeg is free software; you can redistribute it and/or
+ * 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.
*
- * FFmpeg is distributed in the hope that it will be useful,
+ * 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 FFmpeg; if not, write to the Free Software
+ * 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 RTP support for the VP8 payload
* @author Josh Allmann <joshua.allmann@gmail.com>
- * ( http://www.webmproject.org/code/specs/rtp/ )
+ * @see http://tools.ietf.org/html/draft-ietf-payload-vp8-05
*/
#include "libavcodec/bytestream.h"
struct PayloadContext {
AVIOContext *data;
- uint32_t timestamp;
- int is_keyframe;
+ uint32_t timestamp;
+ int is_keyframe;
+ /* If sequence_ok is set, we keep returning data (even if we might have
+ * lost some data, but we haven't lost any too critical data that would
+ * cause the decoder to desynchronize and output random garbage).
+ */
+ int sequence_ok;
+ int first_part_size;
+ uint16_t prev_seq;
+ int prev_pictureid;
+ int broken_frame;
+ /* If sequence_dirty is set, we have lost some data (critical or
+ * non-critical) and decoding will have some sort of artefacts, and
+ * we thus should request a new keyframe.
+ */
+ int sequence_dirty;
+ int got_keyframe;
};
-static void prepare_packet(AVPacket *pkt, PayloadContext *vp8, int stream)
+static void vp8_free_buffer(PayloadContext *vp8)
{
- av_init_packet(pkt);
- pkt->stream_index = stream;
- pkt->flags = vp8->is_keyframe ? AV_PKT_FLAG_KEY : 0;
- pkt->size = url_close_dyn_buf(vp8->data, &pkt->data);
- pkt->destruct = av_destruct_packet;
- vp8->data = NULL;
+ uint8_t *tmp;
+ if (!vp8->data)
+ return;
+ avio_close_dyn_buf(vp8->data, &tmp);
+ av_free(tmp);
+ vp8->data = NULL;
}
-static int vp8_handle_packet(AVFormatContext *ctx,
- PayloadContext *vp8,
- AVStream *st,
- AVPacket *pkt,
- uint32_t *timestamp,
- const uint8_t *buf,
- int len, int flags)
+static int vp8_broken_sequence(AVFormatContext *ctx, PayloadContext *vp8,
+ const char *msg)
{
- int start_packet, end_packet, has_au, ret = AVERROR(EAGAIN);
+ vp8->sequence_ok = 0;
+ av_log(ctx, AV_LOG_WARNING, "%s", msg);
+ vp8_free_buffer(vp8);
+ return AVERROR(EAGAIN);
+}
+
+static int vp8_handle_packet(AVFormatContext *ctx, PayloadContext *vp8,
+ AVStream *st, AVPacket *pkt, uint32_t *timestamp,
+ const uint8_t *buf, int len, uint16_t seq,
+ int flags)
+{
+ int start_partition, end_packet;
+ int extended_bits, part_id;
+ int pictureid_present = 0, tl0picidx_present = 0, tid_present = 0,
+ keyidx_present = 0;
+ int pictureid = -1, pictureid_mask = 0;
+ int returned_old_frame = 0;
+ uint32_t old_timestamp;
if (!buf) {
- // only called when vp8_handle_packet returns 1
- if (!vp8->data) {
- av_log(ctx, AV_LOG_ERROR, "Invalid VP8 data passed\n");
- return AVERROR_INVALIDDATA;
+ if (vp8->data) {
+ int ret = ff_rtp_finalize_packet(pkt, &vp8->data, st->index);
+ if (ret < 0)
+ return ret;
+ *timestamp = vp8->timestamp;
+ if (vp8->sequence_dirty)
+ pkt->flags |= AV_PKT_FLAG_CORRUPT;
+ return 0;
}
- prepare_packet(pkt, vp8, st->index);
- *timestamp = vp8->timestamp;
- return 0;
+ return AVERROR(EAGAIN);
}
- start_packet = *buf & 1;
- end_packet = flags & RTP_FLAG_MARKER;
- has_au = *buf & 2;
+ if (len < 1)
+ return AVERROR_INVALIDDATA;
+
+ extended_bits = buf[0] & 0x80;
+ start_partition = buf[0] & 0x10;
+ part_id = buf[0] & 0x0f;
+ end_packet = flags & RTP_FLAG_MARKER;
buf++;
len--;
+ if (extended_bits) {
+ if (len < 1)
+ return AVERROR_INVALIDDATA;
+ pictureid_present = buf[0] & 0x80;
+ tl0picidx_present = buf[0] & 0x40;
+ tid_present = buf[0] & 0x20;
+ keyidx_present = buf[0] & 0x10;
+ buf++;
+ len--;
+ }
+ if (pictureid_present) {
+ if (len < 1)
+ return AVERROR_INVALIDDATA;
+ if (buf[0] & 0x80) {
+ if (len < 2)
+ return AVERROR_INVALIDDATA;
+ pictureid = AV_RB16(buf) & 0x7fff;
+ pictureid_mask = 0x7fff;
+ buf += 2;
+ len -= 2;
+ } else {
+ pictureid = buf[0] & 0x7f;
+ pictureid_mask = 0x7f;
+ buf++;
+ len--;
+ }
+ }
+ if (tl0picidx_present) {
+ // Ignoring temporal level zero index
+ buf++;
+ len--;
+ }
+ if (tid_present || keyidx_present) {
+ // Ignoring temporal layer index, layer sync bit and keyframe index
+ buf++;
+ len--;
+ }
+ if (len < 1)
+ return AVERROR_INVALIDDATA;
- if (start_packet) {
+ if (start_partition && part_id == 0 && len >= 3) {
int res;
- uint32_t ts = *timestamp;
- if (vp8->data) {
- // missing end marker; return old frame anyway. untested
- prepare_packet(pkt, vp8, st->index);
- *timestamp = vp8->timestamp; // reset timestamp from old frame
-
- // if current frame fits into one rtp packet, need to hold
- // that for the next av_get_packet call
- ret = end_packet ? 1 : 0;
+ int non_key = buf[0] & 0x01;
+ if (!non_key) {
+ vp8_free_buffer(vp8);
+ // Keyframe, decoding ok again
+ vp8->sequence_ok = 1;
+ vp8->sequence_dirty = 0;
+ vp8->got_keyframe = 1;
+ } else {
+ int can_continue = vp8->data && !vp8->is_keyframe &&
+ avio_tell(vp8->data) >= vp8->first_part_size;
+ if (!vp8->sequence_ok)
+ return AVERROR(EAGAIN);
+ if (!vp8->got_keyframe)
+ return vp8_broken_sequence(ctx, vp8, "Keyframe missing\n");
+ if (pictureid >= 0) {
+ if (pictureid != ((vp8->prev_pictureid + 1) & pictureid_mask)) {
+ return vp8_broken_sequence(ctx, vp8,
+ "Missed a picture, sequence broken\n");
+ } else {
+ if (vp8->data && !can_continue)
+ return vp8_broken_sequence(ctx, vp8,
+ "Missed a picture, sequence broken\n");
+ }
+ } else {
+ uint16_t expected_seq = vp8->prev_seq + 1;
+ int16_t diff = seq - expected_seq;
+ if (vp8->data) {
+ // No picture id, so we can't know if missed packets
+ // contained any new frames. If diff == 0, we did get
+ // later packets from the same frame (matching timestamp),
+ // so we know we didn't miss any frame. If diff == 1 and
+ // we still have data (not flushed by the end of frame
+ // marker), the single missed packet must have been part
+ // of the same frame.
+ if ((diff == 0 || diff == 1) && can_continue) {
+ // Proceed with what we have
+ } else {
+ return vp8_broken_sequence(ctx, vp8,
+ "Missed too much, sequence broken\n");
+ }
+ } else {
+ if (diff != 0)
+ return vp8_broken_sequence(ctx, vp8,
+ "Missed unknown data, sequence broken\n");
+ }
+ }
+ if (vp8->data) {
+ vp8->sequence_dirty = 1;
+ if (avio_tell(vp8->data) >= vp8->first_part_size) {
+ int ret = ff_rtp_finalize_packet(pkt, &vp8->data, st->index);
+ if (ret < 0)
+ return ret;
+ pkt->flags |= AV_PKT_FLAG_CORRUPT;
+ returned_old_frame = 1;
+ old_timestamp = vp8->timestamp;
+ } else {
+ // Shouldn't happen
+ vp8_free_buffer(vp8);
+ }
+ }
}
- if ((res = url_open_dyn_buf(&vp8->data)) < 0)
+ vp8->first_part_size = (AV_RL16(&buf[1]) << 3 | buf[0] >> 5) + 3;
+ if ((res = avio_open_dyn_buf(&vp8->data)) < 0)
return res;
- vp8->is_keyframe = *buf & 1;
- vp8->timestamp = ts;
- }
+ vp8->timestamp = *timestamp;
+ vp8->broken_frame = 0;
+ vp8->prev_pictureid = pictureid;
+ vp8->is_keyframe = !non_key;
+ } else {
+ uint16_t expected_seq = vp8->prev_seq + 1;
- if (!vp8->data || vp8->timestamp != *timestamp && ret == AVERROR(EAGAIN)) {
- av_log(ctx, AV_LOG_WARNING,
- "Received no start marker; dropping frame\n");
- return AVERROR(EAGAIN);
- }
+ if (!vp8->sequence_ok)
+ return AVERROR(EAGAIN);
- // cycle through VP8AU headers if needed
- // not tested with actual VP8AUs
- while (len) {
- int au_len = len;
- if (has_au && len > 2) {
- au_len = AV_RB16(buf);
- buf += 2;
- len -= 2;
- if (buf + au_len > buf + len) {
- av_log(ctx, AV_LOG_ERROR, "Invalid VP8AU length\n");
- return AVERROR_INVALIDDATA;
- }
+ if (vp8->timestamp != *timestamp) {
+ // Missed the start of the new frame, sequence broken
+ return vp8_broken_sequence(ctx, vp8,
+ "Received no start marker; dropping frame\n");
}
- avio_write(vp8->data, buf, au_len);
- buf += au_len;
- len -= au_len;
+ if (seq != expected_seq) {
+ if (vp8->is_keyframe) {
+ return vp8_broken_sequence(ctx, vp8,
+ "Missed part of a keyframe, sequence broken\n");
+ } else if (vp8->data && avio_tell(vp8->data) >= vp8->first_part_size) {
+ vp8->broken_frame = 1;
+ vp8->sequence_dirty = 1;
+ } else {
+ return vp8_broken_sequence(ctx, vp8,
+ "Missed part of the first partition, sequence broken\n");
+ }
+ }
}
- if (ret != AVERROR(EAGAIN)) // did we miss a end marker?
- return ret;
+ if (!vp8->data)
+ return vp8_broken_sequence(ctx, vp8, "Received no start marker\n");
+
+ vp8->prev_seq = seq;
+ if (!vp8->broken_frame)
+ avio_write(vp8->data, buf, len);
+
+ if (returned_old_frame) {
+ *timestamp = old_timestamp;
+ return end_packet ? 1 : 0;
+ }
if (end_packet) {
- prepare_packet(pkt, vp8, st->index);
+ int ret;
+ ret = ff_rtp_finalize_packet(pkt, &vp8->data, st->index);
+ if (ret < 0)
+ return ret;
+ if (vp8->sequence_dirty)
+ pkt->flags |= AV_PKT_FLAG_CORRUPT;
return 0;
}
static PayloadContext *vp8_new_context(void)
{
- av_log(NULL, AV_LOG_ERROR, "RTP VP8 payload implementation is incompatible "
- "with the latest spec drafts.\n");
- return av_mallocz(sizeof(PayloadContext));
+ PayloadContext *vp8 = av_mallocz(sizeof(PayloadContext));
+ if (!vp8)
+ return NULL;
+ vp8->sequence_ok = 1;
+ return vp8;
}
static void vp8_free_context(PayloadContext *vp8)
{
- if (vp8->data) {
- uint8_t *tmp;
- url_close_dyn_buf(vp8->data, &tmp);
- av_free(tmp);
- }
+ vp8_free_buffer(vp8);
av_free(vp8);
}
+static int vp8_need_keyframe(PayloadContext *vp8)
+{
+ return vp8->sequence_dirty || !vp8->sequence_ok;
+}
+
RTPDynamicProtocolHandler ff_vp8_dynamic_handler = {
.enc_name = "VP8",
.codec_type = AVMEDIA_TYPE_VIDEO,
- .codec_id = CODEC_ID_VP8,
- .open = vp8_new_context,
- .close = vp8_free_context,
+ .codec_id = AV_CODEC_ID_VP8,
+ .alloc = vp8_new_context,
+ .free = vp8_free_context,
.parse_packet = vp8_handle_packet,
+ .need_keyframe = vp8_need_keyframe,
};
projects / ffmpeg / blobdiff