yading@11: /*
yading@11:  * MOV, 3GP, MP4 muxer RTP hinting
yading@11:  * Copyright (c) 2010 Martin Storsjo
yading@11:  *
yading@11:  * This file is part of FFmpeg.
yading@11:  *
yading@11:  * FFmpeg is free software; you can redistribute it and/or
yading@11:  * modify it under the terms of the GNU Lesser General Public
yading@11:  * License as published by the Free Software Foundation; either
yading@11:  * version 2.1 of the License, or (at your option) any later version.
yading@11:  *
yading@11:  * FFmpeg is distributed in the hope that it will be useful,
yading@11:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@11:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@11:  * Lesser General Public License for more details.
yading@11:  *
yading@11:  * You should have received a copy of the GNU Lesser General Public
yading@11:  * License along with FFmpeg; if not, write to the Free Software
yading@11:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@11:  */
yading@11: 
yading@11: #include "movenc.h"
yading@11: #include "libavutil/intreadwrite.h"
yading@11: #include "internal.h"
yading@11: #include "rtpenc_chain.h"
yading@11: #include "avio_internal.h"
yading@11: #include "rtp.h"
yading@11: 
yading@11: int ff_mov_init_hinting(AVFormatContext *s, int index, int src_index)
yading@11: {
yading@11:     MOVMuxContext *mov  = s->priv_data;
yading@11:     MOVTrack *track     = &mov->tracks[index];
yading@11:     MOVTrack *src_track = &mov->tracks[src_index];
yading@11:     AVStream *src_st    = s->streams[src_index];
yading@11:     int ret = AVERROR(ENOMEM);
yading@11: 
yading@11:     track->tag = MKTAG('r','t','p',' ');
yading@11:     track->src_track = src_index;
yading@11: 
yading@11:     track->enc = avcodec_alloc_context3(NULL);
yading@11:     if (!track->enc)
yading@11:         goto fail;
yading@11:     track->enc->codec_type = AVMEDIA_TYPE_DATA;
yading@11:     track->enc->codec_tag  = track->tag;
yading@11: 
yading@11:     ret = ff_rtp_chain_mux_open(&track->rtp_ctx, s, src_st, NULL,
yading@11:                                 RTP_MAX_PACKET_SIZE, src_index);
yading@11:     if (ret < 0)
yading@11:         goto fail;
yading@11: 
yading@11:     /* Copy the RTP AVStream timebase back to the hint AVStream */
yading@11:     track->timescale = track->rtp_ctx->streams[0]->time_base.den;
yading@11: 
yading@11:     /* Mark the hinted track that packets written to it should be
yading@11:      * sent to this track for hinting. */
yading@11:     src_track->hint_track = index;
yading@11:     return 0;
yading@11: fail:
yading@11:     av_log(s, AV_LOG_WARNING,
yading@11:            "Unable to initialize hinting of stream %d\n", src_index);
yading@11:     av_freep(&track->enc);
yading@11:     /* Set a default timescale, to avoid crashes in av_dump_format */
yading@11:     track->timescale = 90000;
yading@11:     return ret;
yading@11: }
yading@11: 
yading@11: /**
yading@11:  * Remove the first sample from the sample queue.
yading@11:  */
yading@11: static void sample_queue_pop(HintSampleQueue *queue)
yading@11: {
yading@11:     if (queue->len <= 0)
yading@11:         return;
yading@11:     if (queue->samples[0].own_data)
yading@11:         av_free(queue->samples[0].data);
yading@11:     queue->len--;
yading@11:     memmove(queue->samples, queue->samples + 1, sizeof(HintSample)*queue->len);
yading@11: }
yading@11: 
yading@11: /**
yading@11:  * Empty the sample queue, releasing all memory.
yading@11:  */
yading@11: static void sample_queue_free(HintSampleQueue *queue)
yading@11: {
yading@11:     int i;
yading@11:     for (i = 0; i < queue->len; i++)
yading@11:         if (queue->samples[i].own_data)
yading@11:             av_free(queue->samples[i].data);
yading@11:     av_freep(&queue->samples);
yading@11:     queue->len = 0;
yading@11:     queue->size = 0;
yading@11: }
yading@11: 
yading@11: /**
yading@11:  * Add a reference to the sample data to the sample queue. The data is
yading@11:  * not copied. sample_queue_retain should be called before pkt->data
yading@11:  * is reused/freed.
yading@11:  */
yading@11: static void sample_queue_push(HintSampleQueue *queue, uint8_t *data, int size,
yading@11:                               int sample)
yading@11: {
yading@11:     /* No need to keep track of smaller samples, since describing them
yading@11:      * with immediates is more efficient. */
yading@11:     if (size <= 14)
yading@11:         return;
yading@11:     if (!queue->samples || queue->len >= queue->size) {
yading@11:         HintSample* samples;
yading@11:         queue->size += 10;
yading@11:         samples = av_realloc(queue->samples, sizeof(HintSample)*queue->size);
yading@11:         if (!samples)
yading@11:             return;
yading@11:         queue->samples = samples;
yading@11:     }
yading@11:     queue->samples[queue->len].data = data;
yading@11:     queue->samples[queue->len].size = size;
yading@11:     queue->samples[queue->len].sample_number = sample;
yading@11:     queue->samples[queue->len].offset = 0;
yading@11:     queue->samples[queue->len].own_data = 0;
yading@11:     queue->len++;
yading@11: }
yading@11: 
yading@11: /**
yading@11:  * Make local copies of all referenced sample data in the queue.
yading@11:  */
yading@11: static void sample_queue_retain(HintSampleQueue *queue)
yading@11: {
yading@11:     int i;
yading@11:     for (i = 0; i < queue->len; ) {
yading@11:         HintSample *sample = &queue->samples[i];
yading@11:         if (!sample->own_data) {
yading@11:             uint8_t* ptr = av_malloc(sample->size);
yading@11:             if (!ptr) {
yading@11:                 /* Unable to allocate memory for this one, remove it */
yading@11:                 memmove(queue->samples + i, queue->samples + i + 1,
yading@11:                         sizeof(HintSample)*(queue->len - i - 1));
yading@11:                 queue->len--;
yading@11:                 continue;
yading@11:             }
yading@11:             memcpy(ptr, sample->data, sample->size);
yading@11:             sample->data = ptr;
yading@11:             sample->own_data = 1;
yading@11:         }
yading@11:         i++;
yading@11:     }
yading@11: }
yading@11: 
yading@11: /**
yading@11:  * Find matches of needle[n_pos ->] within haystack. If a sufficiently
yading@11:  * large match is found, matching bytes before n_pos are included
yading@11:  * in the match, too (within the limits of the arrays).
yading@11:  *
yading@11:  * @param haystack buffer that may contain parts of needle
yading@11:  * @param h_len length of the haystack buffer
yading@11:  * @param needle buffer containing source data that have been used to
yading@11:  *               construct haystack
yading@11:  * @param n_pos start position in needle used for looking for matches
yading@11:  * @param n_len length of the needle buffer
yading@11:  * @param match_h_offset_ptr offset of the first matching byte within haystack
yading@11:  * @param match_n_offset_ptr offset of the first matching byte within needle
yading@11:  * @param match_len_ptr length of the matched segment
yading@11:  * @return 0 if a match was found, < 0 if no match was found
yading@11:  */
yading@11: static int match_segments(const uint8_t *haystack, int h_len,
yading@11:                           const uint8_t *needle, int n_pos, int n_len,
yading@11:                           int *match_h_offset_ptr, int *match_n_offset_ptr,
yading@11:                           int *match_len_ptr)
yading@11: {
yading@11:     int h_pos;
yading@11:     for (h_pos = 0; h_pos < h_len; h_pos++) {
yading@11:         int match_len = 0;
yading@11:         int match_h_pos, match_n_pos;
yading@11: 
yading@11:         /* Check how many bytes match at needle[n_pos] and haystack[h_pos] */
yading@11:         while (h_pos + match_len < h_len && n_pos + match_len < n_len &&
yading@11:                needle[n_pos + match_len] == haystack[h_pos + match_len])
yading@11:             match_len++;
yading@11:         if (match_len <= 8)
yading@11:             continue;
yading@11: 
yading@11:         /* If a sufficiently large match was found, try to expand
yading@11:          * the matched segment backwards. */
yading@11:         match_h_pos = h_pos;
yading@11:         match_n_pos = n_pos;
yading@11:         while (match_n_pos > 0 && match_h_pos > 0 &&
yading@11:                needle[match_n_pos - 1] == haystack[match_h_pos - 1]) {
yading@11:             match_n_pos--;
yading@11:             match_h_pos--;
yading@11:             match_len++;
yading@11:         }
yading@11:         if (match_len <= 14)
yading@11:             continue;
yading@11:         *match_h_offset_ptr = match_h_pos;
yading@11:         *match_n_offset_ptr = match_n_pos;
yading@11:         *match_len_ptr = match_len;
yading@11:         return 0;
yading@11:     }
yading@11:     return -1;
yading@11: }
yading@11: 
yading@11: /**
yading@11:  * Look for segments in samples in the sample queue matching the data
yading@11:  * in ptr. Samples not matching are removed from the queue. If a match
yading@11:  * is found, the next time it will look for matches starting from the
yading@11:  * end of the previous matched segment.
yading@11:  *
yading@11:  * @param data data to find matches for in the sample queue
yading@11:  * @param len length of the data buffer
yading@11:  * @param queue samples used for looking for matching segments
yading@11:  * @param pos the offset in data of the matched segment
yading@11:  * @param match_sample the number of the sample that contained the match
yading@11:  * @param match_offset the offset of the matched segment within the sample
yading@11:  * @param match_len the length of the matched segment
yading@11:  * @return 0 if a match was found, < 0 if no match was found
yading@11:  */
yading@11: static int find_sample_match(const uint8_t *data, int len,
yading@11:                              HintSampleQueue *queue, int *pos,
yading@11:                              int *match_sample, int *match_offset,
yading@11:                              int *match_len)
yading@11: {
yading@11:     while (queue->len > 0) {
yading@11:         HintSample *sample = &queue->samples[0];
yading@11:         /* If looking for matches in a new sample, skip the first 5 bytes,
yading@11:          * since they often may be modified/removed in the output packet. */
yading@11:         if (sample->offset == 0 && sample->size > 5)
yading@11:             sample->offset = 5;
yading@11: 
yading@11:         if (match_segments(data, len, sample->data, sample->offset,
yading@11:                            sample->size, pos, match_offset, match_len) == 0) {
yading@11:             *match_sample = sample->sample_number;
yading@11:             /* Next time, look for matches at this offset, with a little
yading@11:              * margin to this match. */
yading@11:             sample->offset = *match_offset + *match_len + 5;
yading@11:             if (sample->offset + 10 >= sample->size)
yading@11:                 sample_queue_pop(queue); /* Not enough useful data left */
yading@11:             return 0;
yading@11:         }
yading@11: 
yading@11:         if (sample->offset < 10 && sample->size > 20) {
yading@11:             /* No match found from the start of the sample,
yading@11:              * try from the middle of the sample instead. */
yading@11:             sample->offset = sample->size/2;
yading@11:         } else {
yading@11:             /* No match for this sample, remove it */
yading@11:             sample_queue_pop(queue);
yading@11:         }
yading@11:     }
yading@11:     return -1;
yading@11: }
yading@11: 
yading@11: static void output_immediate(const uint8_t *data, int size,
yading@11:                              AVIOContext *out, int *entries)
yading@11: {
yading@11:     while (size > 0) {
yading@11:         int len = size;
yading@11:         if (len > 14)
yading@11:             len = 14;
yading@11:         avio_w8(out, 1); /* immediate constructor */
yading@11:         avio_w8(out, len); /* amount of valid data */
yading@11:         avio_write(out, data, len);
yading@11:         data += len;
yading@11:         size -= len;
yading@11: 
yading@11:         for (; len < 14; len++)
yading@11:             avio_w8(out, 0);
yading@11: 
yading@11:         (*entries)++;
yading@11:     }
yading@11: }
yading@11: 
yading@11: static void output_match(AVIOContext *out, int match_sample,
yading@11:                          int match_offset, int match_len, int *entries)
yading@11: {
yading@11:     avio_w8(out, 2); /* sample constructor */
yading@11:     avio_w8(out, 0); /* track reference */
yading@11:     avio_wb16(out, match_len);
yading@11:     avio_wb32(out, match_sample);
yading@11:     avio_wb32(out, match_offset);
yading@11:     avio_wb16(out, 1); /* bytes per block */
yading@11:     avio_wb16(out, 1); /* samples per block */
yading@11:     (*entries)++;
yading@11: }
yading@11: 
yading@11: static void describe_payload(const uint8_t *data, int size,
yading@11:                              AVIOContext *out, int *entries,
yading@11:                              HintSampleQueue *queue)
yading@11: {
yading@11:     /* Describe the payload using different constructors */
yading@11:     while (size > 0) {
yading@11:         int match_sample, match_offset, match_len, pos;
yading@11:         if (find_sample_match(data, size, queue, &pos, &match_sample,
yading@11:                               &match_offset, &match_len) < 0)
yading@11:             break;
yading@11:         output_immediate(data, pos, out, entries);
yading@11:         data += pos;
yading@11:         size -= pos;
yading@11:         output_match(out, match_sample, match_offset, match_len, entries);
yading@11:         data += match_len;
yading@11:         size -= match_len;
yading@11:     }
yading@11:     output_immediate(data, size, out, entries);
yading@11: }
yading@11: 
yading@11: /**
yading@11:  * Write an RTP hint (that may contain one or more RTP packets)
yading@11:  * for the packets in data. data contains one or more packets with a
yading@11:  * BE32 size header.
yading@11:  *
yading@11:  * @param out buffer where the hints are written
yading@11:  * @param data buffer containing RTP packets
yading@11:  * @param size the size of the data buffer
yading@11:  * @param trk the MOVTrack for the hint track
yading@11:  * @param pts pointer where the timestamp for the written RTP hint is stored
yading@11:  * @return the number of RTP packets in the written hint
yading@11:  */
yading@11: static int write_hint_packets(AVIOContext *out, const uint8_t *data,
yading@11:                               int size, MOVTrack *trk, int64_t *pts)
yading@11: {
yading@11:     int64_t curpos;
yading@11:     int64_t count_pos, entries_pos;
yading@11:     int count = 0, entries;
yading@11: 
yading@11:     count_pos = avio_tell(out);
yading@11:     /* RTPsample header */
yading@11:     avio_wb16(out, 0); /* packet count */
yading@11:     avio_wb16(out, 0); /* reserved */
yading@11: 
yading@11:     while (size > 4) {
yading@11:         uint32_t packet_len = AV_RB32(data);
yading@11:         uint16_t seq;
yading@11:         uint32_t ts;
yading@11: 
yading@11:         data += 4;
yading@11:         size -= 4;
yading@11:         if (packet_len > size || packet_len <= 12)
yading@11:             break;
yading@11:         if (RTP_PT_IS_RTCP(data[1])) {
yading@11:             /* RTCP packet, just skip */
yading@11:             data += packet_len;
yading@11:             size -= packet_len;
yading@11:             continue;
yading@11:         }
yading@11: 
yading@11:         if (packet_len > trk->max_packet_size)
yading@11:             trk->max_packet_size = packet_len;
yading@11: 
yading@11:         seq = AV_RB16(&data[2]);
yading@11:         ts = AV_RB32(&data[4]);
yading@11: 
yading@11:         if (trk->prev_rtp_ts == 0)
yading@11:             trk->prev_rtp_ts = ts;
yading@11:         /* Unwrap the 32-bit RTP timestamp that wraps around often
yading@11:          * into a not (as often) wrapping 64-bit timestamp. */
yading@11:         trk->cur_rtp_ts_unwrapped += (int32_t) (ts - trk->prev_rtp_ts);
yading@11:         trk->prev_rtp_ts = ts;
yading@11:         if (*pts == AV_NOPTS_VALUE)
yading@11:             *pts = trk->cur_rtp_ts_unwrapped;
yading@11: 
yading@11:         count++;
yading@11:         /* RTPpacket header */
yading@11:         avio_wb32(out, 0); /* relative_time */
yading@11:         avio_write(out, data, 2); /* RTP header */
yading@11:         avio_wb16(out, seq); /* RTPsequenceseed */
yading@11:         avio_wb16(out, 0); /* reserved + flags */
yading@11:         entries_pos = avio_tell(out);
yading@11:         avio_wb16(out, 0); /* entry count */
yading@11: 
yading@11:         data += 12;
yading@11:         size -= 12;
yading@11:         packet_len -= 12;
yading@11: 
yading@11:         entries = 0;
yading@11:         /* Write one or more constructors describing the payload data */
yading@11:         describe_payload(data, packet_len, out, &entries, &trk->sample_queue);
yading@11:         data += packet_len;
yading@11:         size -= packet_len;
yading@11: 
yading@11:         curpos = avio_tell(out);
yading@11:         avio_seek(out, entries_pos, SEEK_SET);
yading@11:         avio_wb16(out, entries);
yading@11:         avio_seek(out, curpos, SEEK_SET);
yading@11:     }
yading@11: 
yading@11:     curpos = avio_tell(out);
yading@11:     avio_seek(out, count_pos, SEEK_SET);
yading@11:     avio_wb16(out, count);
yading@11:     avio_seek(out, curpos, SEEK_SET);
yading@11:     return count;
yading@11: }
yading@11: 
yading@11: int ff_mov_add_hinted_packet(AVFormatContext *s, AVPacket *pkt,
yading@11:                              int track_index, int sample,
yading@11:                              uint8_t *sample_data, int sample_size)
yading@11: {
yading@11:     MOVMuxContext *mov = s->priv_data;
yading@11:     MOVTrack *trk = &mov->tracks[track_index];
yading@11:     AVFormatContext *rtp_ctx = trk->rtp_ctx;
yading@11:     uint8_t *buf = NULL;
yading@11:     int size;
yading@11:     AVIOContext *hintbuf = NULL;
yading@11:     AVPacket hint_pkt;
yading@11:     int ret = 0, count;
yading@11: 
yading@11:     if (!rtp_ctx)
yading@11:         return AVERROR(ENOENT);
yading@11:     if (!rtp_ctx->pb)
yading@11:         return AVERROR(ENOMEM);
yading@11: 
yading@11:     if (sample_data)
yading@11:         sample_queue_push(&trk->sample_queue, sample_data, sample_size, sample);
yading@11:     else
yading@11:         sample_queue_push(&trk->sample_queue, pkt->data, pkt->size, sample);
yading@11: 
yading@11:     /* Feed the packet to the RTP muxer */
yading@11:     ff_write_chained(rtp_ctx, 0, pkt, s);
yading@11: 
yading@11:     /* Fetch the output from the RTP muxer, open a new output buffer
yading@11:      * for next time. */
yading@11:     size = avio_close_dyn_buf(rtp_ctx->pb, &buf);
yading@11:     if ((ret = ffio_open_dyn_packet_buf(&rtp_ctx->pb,
yading@11:                                        RTP_MAX_PACKET_SIZE)) < 0)
yading@11:         goto done;
yading@11: 
yading@11:     if (size <= 0)
yading@11:         goto done;
yading@11: 
yading@11:     /* Open a buffer for writing the hint */
yading@11:     if ((ret = avio_open_dyn_buf(&hintbuf)) < 0)
yading@11:         goto done;
yading@11:     av_init_packet(&hint_pkt);
yading@11:     count = write_hint_packets(hintbuf, buf, size, trk, &hint_pkt.dts);
yading@11:     av_freep(&buf);
yading@11: 
yading@11:     /* Write the hint data into the hint track */
yading@11:     hint_pkt.size = size = avio_close_dyn_buf(hintbuf, &buf);
yading@11:     hint_pkt.data = buf;
yading@11:     hint_pkt.pts  = hint_pkt.dts;
yading@11:     hint_pkt.stream_index = track_index;
yading@11:     if (pkt->flags & AV_PKT_FLAG_KEY)
yading@11:         hint_pkt.flags |= AV_PKT_FLAG_KEY;
yading@11:     if (count > 0)
yading@11:         ff_mov_write_packet(s, &hint_pkt);
yading@11: done:
yading@11:     av_free(buf);
yading@11:     sample_queue_retain(&trk->sample_queue);
yading@11:     return ret;
yading@11: }
yading@11: 
yading@11: void ff_mov_close_hinting(MOVTrack *track) {
yading@11:     AVFormatContext* rtp_ctx = track->rtp_ctx;
yading@11:     uint8_t *ptr;
yading@11: 
yading@11:     av_freep(&track->enc);
yading@11:     sample_queue_free(&track->sample_queue);
yading@11:     if (!rtp_ctx)
yading@11:         return;
yading@11:     if (rtp_ctx->pb) {
yading@11:         av_write_trailer(rtp_ctx);
yading@11:         avio_close_dyn_buf(rtp_ctx->pb, &ptr);
yading@11:         av_free(ptr);
yading@11:     }
yading@11:     avformat_free_context(rtp_ctx);
yading@11: }