| /* |
| * 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_freep(&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_freep(&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, 0); |
| |
| /* 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; |
| |
| av_freep(&track->enc); |
| sample_queue_free(&track->sample_queue); |
| if (!rtp_ctx) |
| return; |
| if (rtp_ctx->pb) { |
| av_write_trailer(rtp_ctx); |
| ffio_free_dyn_buf(&rtp_ctx->pb); |
| } |
| avformat_free_context(rtp_ctx); |
| } |
