diff options
Diffstat (limited to 'ffmpeg1/libavformat/movenchint.c')
| -rw-r--r-- | ffmpeg1/libavformat/movenchint.c | 462 |
1 files changed, 462 insertions, 0 deletions
diff --git a/ffmpeg1/libavformat/movenchint.c b/ffmpeg1/libavformat/movenchint.c new file mode 100644 index 0000000..cc90f0b --- /dev/null +++ b/ffmpeg1/libavformat/movenchint.c @@ -0,0 +1,462 @@ +/* + * 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; + queue->size += 10; + samples = av_realloc(queue->samples, sizeof(HintSample)*queue->size); + if (!samples) + return; + 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 pts 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 *pts) +{ + 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; + + 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. */ + trk->cur_rtp_ts_unwrapped += (int32_t) (ts - trk->prev_rtp_ts); + trk->prev_rtp_ts = ts; + if (*pts == AV_NOPTS_VALUE) + *pts = 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, 0); /* reserved + flags */ + entries_pos = avio_tell(out); + avio_wb16(out, 0); /* entry count */ + + 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); +} |