0,0 → 1,474 |
/* |
* MOV, 3GP, MP4 muxer RTP hinting |
* Copyright (c) 2010 Martin Storsjo |
* |
* 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 |
*/ |
|
#include "movenc.h" |
#include "libavutil/intreadwrite.h" |
#include "internal.h" |
#include "rtpenc_chain.h" |
#include "avio_internal.h" |
#include "rtp.h" |
|
int ff_mov_init_hinting(AVFormatContext *s, int index, int src_index) |
{ |
MOVMuxContext *mov = s->priv_data; |
MOVTrack *track = &mov->tracks[index]; |
MOVTrack *src_track = &mov->tracks[src_index]; |
AVStream *src_st = s->streams[src_index]; |
int ret = AVERROR(ENOMEM); |
|
track->tag = MKTAG('r','t','p',' '); |
track->src_track = src_index; |
|
track->enc = avcodec_alloc_context3(NULL); |
if (!track->enc) |
goto fail; |
track->enc->codec_type = AVMEDIA_TYPE_DATA; |
track->enc->codec_tag = track->tag; |
|
ret = ff_rtp_chain_mux_open(&track->rtp_ctx, s, src_st, NULL, |
RTP_MAX_PACKET_SIZE, src_index); |
if (ret < 0) |
goto fail; |
|
/* Copy the RTP AVStream timebase back to the hint AVStream */ |
track->timescale = track->rtp_ctx->streams[0]->time_base.den; |
|
/* Mark the hinted track that packets written to it should be |
* sent to this track for hinting. */ |
src_track->hint_track = index; |
return 0; |
fail: |
av_log(s, AV_LOG_WARNING, |
"Unable to initialize hinting of stream %d\n", src_index); |
av_freep(&track->enc); |
/* Set a default timescale, to avoid crashes in av_dump_format */ |
track->timescale = 90000; |
return ret; |
} |
|
/** |
* Remove the first sample from the sample queue. |
*/ |
static void sample_queue_pop(HintSampleQueue *queue) |
{ |
if (queue->len <= 0) |
return; |
if (queue->samples[0].own_data) |
av_free(queue->samples[0].data); |
queue->len--; |
memmove(queue->samples, queue->samples + 1, sizeof(HintSample)*queue->len); |
} |
|
/** |
* Empty the sample queue, releasing all memory. |
*/ |
static void sample_queue_free(HintSampleQueue *queue) |
{ |
int i; |
for (i = 0; i < queue->len; i++) |
if (queue->samples[i].own_data) |
av_free(queue->samples[i].data); |
av_freep(&queue->samples); |
queue->len = 0; |
queue->size = 0; |
} |
|
/** |
* Add a reference to the sample data to the sample queue. The data is |
* not copied. sample_queue_retain should be called before pkt->data |
* is reused/freed. |
*/ |
static void sample_queue_push(HintSampleQueue *queue, uint8_t *data, int size, |
int sample) |
{ |
/* No need to keep track of smaller samples, since describing them |
* with immediates is more efficient. */ |
if (size <= 14) |
return; |
if (!queue->samples || queue->len >= queue->size) { |
HintSample *samples; |
samples = av_realloc_array(queue->samples, queue->size + 10, sizeof(HintSample)); |
if (!samples) |
return; |
queue->size += 10; |
queue->samples = samples; |
} |
queue->samples[queue->len].data = data; |
queue->samples[queue->len].size = size; |
queue->samples[queue->len].sample_number = sample; |
queue->samples[queue->len].offset = 0; |
queue->samples[queue->len].own_data = 0; |
queue->len++; |
} |
|
/** |
* Make local copies of all referenced sample data in the queue. |
*/ |
static void sample_queue_retain(HintSampleQueue *queue) |
{ |
int i; |
for (i = 0; i < queue->len; ) { |
HintSample *sample = &queue->samples[i]; |
if (!sample->own_data) { |
uint8_t *ptr = av_malloc(sample->size); |
if (!ptr) { |
/* Unable to allocate memory for this one, remove it */ |
memmove(queue->samples + i, queue->samples + i + 1, |
sizeof(HintSample)*(queue->len - i - 1)); |
queue->len--; |
continue; |
} |
memcpy(ptr, sample->data, sample->size); |
sample->data = ptr; |
sample->own_data = 1; |
} |
i++; |
} |
} |
|
/** |
* Find matches of needle[n_pos ->] within haystack. If a sufficiently |
* large match is found, matching bytes before n_pos are included |
* in the match, too (within the limits of the arrays). |
* |
* @param haystack buffer that may contain parts of needle |
* @param h_len length of the haystack buffer |
* @param needle buffer containing source data that have been used to |
* construct haystack |
* @param n_pos start position in needle used for looking for matches |
* @param n_len length of the needle buffer |
* @param match_h_offset_ptr offset of the first matching byte within haystack |
* @param match_n_offset_ptr offset of the first matching byte within needle |
* @param match_len_ptr length of the matched segment |
* @return 0 if a match was found, < 0 if no match was found |
*/ |
static int match_segments(const uint8_t *haystack, int h_len, |
const uint8_t *needle, int n_pos, int n_len, |
int *match_h_offset_ptr, int *match_n_offset_ptr, |
int *match_len_ptr) |
{ |
int h_pos; |
for (h_pos = 0; h_pos < h_len; h_pos++) { |
int match_len = 0; |
int match_h_pos, match_n_pos; |
|
/* Check how many bytes match at needle[n_pos] and haystack[h_pos] */ |
while (h_pos + match_len < h_len && n_pos + match_len < n_len && |
needle[n_pos + match_len] == haystack[h_pos + match_len]) |
match_len++; |
if (match_len <= 8) |
continue; |
|
/* If a sufficiently large match was found, try to expand |
* the matched segment backwards. */ |
match_h_pos = h_pos; |
match_n_pos = n_pos; |
while (match_n_pos > 0 && match_h_pos > 0 && |
needle[match_n_pos - 1] == haystack[match_h_pos - 1]) { |
match_n_pos--; |
match_h_pos--; |
match_len++; |
} |
if (match_len <= 14) |
continue; |
*match_h_offset_ptr = match_h_pos; |
*match_n_offset_ptr = match_n_pos; |
*match_len_ptr = match_len; |
return 0; |
} |
return -1; |
} |
|
/** |
* Look for segments in samples in the sample queue matching the data |
* in ptr. Samples not matching are removed from the queue. If a match |
* is found, the next time it will look for matches starting from the |
* end of the previous matched segment. |
* |
* @param data data to find matches for in the sample queue |
* @param len length of the data buffer |
* @param queue samples used for looking for matching segments |
* @param pos the offset in data of the matched segment |
* @param match_sample the number of the sample that contained the match |
* @param match_offset the offset of the matched segment within the sample |
* @param match_len the length of the matched segment |
* @return 0 if a match was found, < 0 if no match was found |
*/ |
static int find_sample_match(const uint8_t *data, int len, |
HintSampleQueue *queue, int *pos, |
int *match_sample, int *match_offset, |
int *match_len) |
{ |
while (queue->len > 0) { |
HintSample *sample = &queue->samples[0]; |
/* If looking for matches in a new sample, skip the first 5 bytes, |
* since they often may be modified/removed in the output packet. */ |
if (sample->offset == 0 && sample->size > 5) |
sample->offset = 5; |
|
if (match_segments(data, len, sample->data, sample->offset, |
sample->size, pos, match_offset, match_len) == 0) { |
*match_sample = sample->sample_number; |
/* Next time, look for matches at this offset, with a little |
* margin to this match. */ |
sample->offset = *match_offset + *match_len + 5; |
if (sample->offset + 10 >= sample->size) |
sample_queue_pop(queue); /* Not enough useful data left */ |
return 0; |
} |
|
if (sample->offset < 10 && sample->size > 20) { |
/* No match found from the start of the sample, |
* try from the middle of the sample instead. */ |
sample->offset = sample->size/2; |
} else { |
/* No match for this sample, remove it */ |
sample_queue_pop(queue); |
} |
} |
return -1; |
} |
|
static void output_immediate(const uint8_t *data, int size, |
AVIOContext *out, int *entries) |
{ |
while (size > 0) { |
int len = size; |
if (len > 14) |
len = 14; |
avio_w8(out, 1); /* immediate constructor */ |
avio_w8(out, len); /* amount of valid data */ |
avio_write(out, data, len); |
data += len; |
size -= len; |
|
for (; len < 14; len++) |
avio_w8(out, 0); |
|
(*entries)++; |
} |
} |
|
static void output_match(AVIOContext *out, int match_sample, |
int match_offset, int match_len, int *entries) |
{ |
avio_w8(out, 2); /* sample constructor */ |
avio_w8(out, 0); /* track reference */ |
avio_wb16(out, match_len); |
avio_wb32(out, match_sample); |
avio_wb32(out, match_offset); |
avio_wb16(out, 1); /* bytes per block */ |
avio_wb16(out, 1); /* samples per block */ |
(*entries)++; |
} |
|
static void describe_payload(const uint8_t *data, int size, |
AVIOContext *out, int *entries, |
HintSampleQueue *queue) |
{ |
/* Describe the payload using different constructors */ |
while (size > 0) { |
int match_sample, match_offset, match_len, pos; |
if (find_sample_match(data, size, queue, &pos, &match_sample, |
&match_offset, &match_len) < 0) |
break; |
output_immediate(data, pos, out, entries); |
data += pos; |
size -= pos; |
output_match(out, match_sample, match_offset, match_len, entries); |
data += match_len; |
size -= match_len; |
} |
output_immediate(data, size, out, entries); |
} |
|
/** |
* Write an RTP hint (that may contain one or more RTP packets) |
* for the packets in data. data contains one or more packets with a |
* BE32 size header. |
* |
* @param out buffer where the hints are written |
* @param data buffer containing RTP packets |
* @param size the size of the data buffer |
* @param trk the MOVTrack for the hint track |
* @param dts pointer where the timestamp for the written RTP hint is stored |
* @return the number of RTP packets in the written hint |
*/ |
static int write_hint_packets(AVIOContext *out, const uint8_t *data, |
int size, MOVTrack *trk, int64_t *dts) |
{ |
int64_t curpos; |
int64_t count_pos, entries_pos; |
int count = 0, entries; |
|
count_pos = avio_tell(out); |
/* RTPsample header */ |
avio_wb16(out, 0); /* packet count */ |
avio_wb16(out, 0); /* reserved */ |
|
while (size > 4) { |
uint32_t packet_len = AV_RB32(data); |
uint16_t seq; |
uint32_t ts; |
int32_t ts_diff; |
|
data += 4; |
size -= 4; |
if (packet_len > size || packet_len <= 12) |
break; |
if (RTP_PT_IS_RTCP(data[1])) { |
/* RTCP packet, just skip */ |
data += packet_len; |
size -= packet_len; |
continue; |
} |
|
if (packet_len > trk->max_packet_size) |
trk->max_packet_size = packet_len; |
|
seq = AV_RB16(&data[2]); |
ts = AV_RB32(&data[4]); |
|
if (trk->prev_rtp_ts == 0) |
trk->prev_rtp_ts = ts; |
/* Unwrap the 32-bit RTP timestamp that wraps around often |
* into a not (as often) wrapping 64-bit timestamp. */ |
ts_diff = ts - trk->prev_rtp_ts; |
if (ts_diff > 0) { |
trk->cur_rtp_ts_unwrapped += ts_diff; |
trk->prev_rtp_ts = ts; |
ts_diff = 0; |
} |
if (*dts == AV_NOPTS_VALUE) |
*dts = trk->cur_rtp_ts_unwrapped; |
|
count++; |
/* RTPpacket header */ |
avio_wb32(out, 0); /* relative_time */ |
avio_write(out, data, 2); /* RTP header */ |
avio_wb16(out, seq); /* RTPsequenceseed */ |
avio_wb16(out, ts_diff ? 4 : 0); /* reserved + flags (extra_flag) */ |
entries_pos = avio_tell(out); |
avio_wb16(out, 0); /* entry count */ |
if (ts_diff) { /* if extra_flag is set */ |
avio_wb32(out, 16); /* extra_information_length */ |
avio_wb32(out, 12); /* rtpoffsetTLV box */ |
avio_write(out, "rtpo", 4); |
avio_wb32(out, ts_diff); |
} |
|
data += 12; |
size -= 12; |
packet_len -= 12; |
|
entries = 0; |
/* Write one or more constructors describing the payload data */ |
describe_payload(data, packet_len, out, &entries, &trk->sample_queue); |
data += packet_len; |
size -= packet_len; |
|
curpos = avio_tell(out); |
avio_seek(out, entries_pos, SEEK_SET); |
avio_wb16(out, entries); |
avio_seek(out, curpos, SEEK_SET); |
} |
|
curpos = avio_tell(out); |
avio_seek(out, count_pos, SEEK_SET); |
avio_wb16(out, count); |
avio_seek(out, curpos, SEEK_SET); |
return count; |
} |
|
int ff_mov_add_hinted_packet(AVFormatContext *s, AVPacket *pkt, |
int track_index, int sample, |
uint8_t *sample_data, int sample_size) |
{ |
MOVMuxContext *mov = s->priv_data; |
MOVTrack *trk = &mov->tracks[track_index]; |
AVFormatContext *rtp_ctx = trk->rtp_ctx; |
uint8_t *buf = NULL; |
int size; |
AVIOContext *hintbuf = NULL; |
AVPacket hint_pkt; |
int ret = 0, count; |
|
if (!rtp_ctx) |
return AVERROR(ENOENT); |
if (!rtp_ctx->pb) |
return AVERROR(ENOMEM); |
|
if (sample_data) |
sample_queue_push(&trk->sample_queue, sample_data, sample_size, sample); |
else |
sample_queue_push(&trk->sample_queue, pkt->data, pkt->size, sample); |
|
/* Feed the packet to the RTP muxer */ |
ff_write_chained(rtp_ctx, 0, pkt, s); |
|
/* Fetch the output from the RTP muxer, open a new output buffer |
* for next time. */ |
size = avio_close_dyn_buf(rtp_ctx->pb, &buf); |
if ((ret = ffio_open_dyn_packet_buf(&rtp_ctx->pb, |
RTP_MAX_PACKET_SIZE)) < 0) |
goto done; |
|
if (size <= 0) |
goto done; |
|
/* Open a buffer for writing the hint */ |
if ((ret = avio_open_dyn_buf(&hintbuf)) < 0) |
goto done; |
av_init_packet(&hint_pkt); |
count = write_hint_packets(hintbuf, buf, size, trk, &hint_pkt.dts); |
av_freep(&buf); |
|
/* Write the hint data into the hint track */ |
hint_pkt.size = size = avio_close_dyn_buf(hintbuf, &buf); |
hint_pkt.data = buf; |
hint_pkt.pts = hint_pkt.dts; |
hint_pkt.stream_index = track_index; |
if (pkt->flags & AV_PKT_FLAG_KEY) |
hint_pkt.flags |= AV_PKT_FLAG_KEY; |
if (count > 0) |
ff_mov_write_packet(s, &hint_pkt); |
done: |
av_free(buf); |
sample_queue_retain(&trk->sample_queue); |
return ret; |
} |
|
void ff_mov_close_hinting(MOVTrack *track) |
{ |
AVFormatContext *rtp_ctx = track->rtp_ctx; |
uint8_t *ptr; |
|
av_freep(&track->enc); |
sample_queue_free(&track->sample_queue); |
if (!rtp_ctx) |
return; |
if (rtp_ctx->pb) { |
av_write_trailer(rtp_ctx); |
avio_close_dyn_buf(rtp_ctx->pb, &ptr); |
av_free(ptr); |
} |
avformat_free_context(rtp_ctx); |
} |