#define MAX_TOC_ENTRIES 16
#define MAX_DICTIONARY_ENTRIES 128
#define TEA_BLOCK_SIZE 8
+#define CHAPTER_HEADER_SIZE 8
+#define TIMEPREC 1000
+#define MP3_FRAME_SIZE 104
typedef struct AADemuxContext {
AVClass *class;
struct AVTEA *tea_ctx;
uint8_t file_key[16];
int64_t current_chapter_size;
+ int64_t content_start;
+ int64_t content_end;
+ int seek_offset;
} AADemuxContext;
static int get_second_size(char *codec_name)
uint32_t nkey, nval, toc_size, npairs, header_seed = 0, start;
char key[128], val[128], codec_name[64] = {0};
uint8_t output[24], dst[8], src[8];
- int64_t largest_size = -1, current_size = -1;
+ int64_t largest_size = -1, current_size = -1, chapter_pos;
struct toc_entry {
uint32_t offset;
uint32_t size;
st->codecpar->codec_id = AV_CODEC_ID_MP3;
st->codecpar->sample_rate = 22050;
st->need_parsing = AVSTREAM_PARSE_FULL_RAW;
- st->start_time = 0;
+ avpriv_set_pts_info(st, 64, 8, 32000 * TIMEPREC);
+ // encoded audio frame is MP3_FRAME_SIZE bytes (+1 with padding, unlikely)
} else if (!strcmp(codec_name, "acelp85")) {
st->codecpar->codec_id = AV_CODEC_ID_SIPR;
st->codecpar->block_align = 19;
st->codecpar->channels = 1;
st->codecpar->sample_rate = 8500;
+ st->codecpar->bit_rate = 8500;
st->need_parsing = AVSTREAM_PARSE_FULL_RAW;
+ avpriv_set_pts_info(st, 64, 8, 8500 * TIMEPREC);
} else if (!strcmp(codec_name, "acelp16")) {
st->codecpar->codec_id = AV_CODEC_ID_SIPR;
st->codecpar->block_align = 20;
st->codecpar->channels = 1;
st->codecpar->sample_rate = 16000;
+ st->codecpar->bit_rate = 16000;
st->need_parsing = AVSTREAM_PARSE_FULL_RAW;
+ avpriv_set_pts_info(st, 64, 8, 16000 * TIMEPREC);
}
/* determine, and jump to audio start offset */
}
start = TOC[largest_idx].offset;
avio_seek(pb, start, SEEK_SET);
+
+ // extract chapter positions. since all formats have constant bit rate, use it
+ // as time base in bytes/s, for easy stream position <-> timestamp conversion
+ st->start_time = 0;
+ c->content_start = start;
+ c->content_end = start + largest_size;
+
+ while ((chapter_pos = avio_tell(pb)) >= 0 && chapter_pos < c->content_end) {
+ int chapter_idx = s->nb_chapters;
+ uint32_t chapter_size = avio_rb32(pb);
+ if (chapter_size == 0) break;
+ chapter_pos -= start + CHAPTER_HEADER_SIZE * chapter_idx;
+ avio_skip(pb, 4 + chapter_size);
+ if (!avpriv_new_chapter(s, chapter_idx, st->time_base,
+ chapter_pos * TIMEPREC, (chapter_pos + chapter_size) * TIMEPREC, NULL))
+ return AVERROR(ENOMEM);
+ }
+
+ st->duration = (largest_size - CHAPTER_HEADER_SIZE * s->nb_chapters) * TIMEPREC;
+
+ ff_update_cur_dts(s, st, 0);
+ avio_seek(pb, start, SEEK_SET);
c->current_chapter_size = 0;
+ c->seek_offset = 0;
return 0;
}
int written = 0;
int ret;
AADemuxContext *c = s->priv_data;
+ uint64_t pos = avio_tell(s->pb);
+
+ // are we at the end of the audio content?
+ if (pos >= c->content_end) {
+ return AVERROR_EOF;
+ }
// are we at the start of a chapter?
if (c->current_chapter_size == 0) {
av_log(s, AV_LOG_DEBUG, "Chapter %d (%" PRId64 " bytes)\n", c->chapter_idx, c->current_chapter_size);
c->chapter_idx = c->chapter_idx + 1;
avio_skip(s->pb, 4); // data start offset
+ pos += 8;
c->current_codec_second_size = c->codec_second_size;
}
// decrypt c->current_codec_second_size bytes
blocks = c->current_codec_second_size / TEA_BLOCK_SIZE;
for (i = 0; i < blocks; i++) {
- avio_read(s->pb, src, TEA_BLOCK_SIZE);
+ ret = avio_read(s->pb, src, TEA_BLOCK_SIZE);
+ if (ret != TEA_BLOCK_SIZE)
+ return (ret < 0) ? ret : AVERROR_EOF;
av_tea_init(c->tea_ctx, c->file_key, 16);
av_tea_crypt(c->tea_ctx, dst, src, 1, NULL, 1);
memcpy(buf + written, dst, TEA_BLOCK_SIZE);
}
trailing_bytes = c->current_codec_second_size % TEA_BLOCK_SIZE;
if (trailing_bytes != 0) { // trailing bytes are left unencrypted!
- avio_read(s->pb, src, trailing_bytes);
+ ret = avio_read(s->pb, src, trailing_bytes);
+ if (ret != trailing_bytes)
+ return (ret < 0) ? ret : AVERROR_EOF;
memcpy(buf + written, src, trailing_bytes);
written = written + trailing_bytes;
}
if (c->current_chapter_size <= 0)
c->current_chapter_size = 0;
- ret = av_new_packet(pkt, written);
+ if (c->seek_offset > written)
+ c->seek_offset = 0; // ignore wrong estimate
+
+ ret = av_new_packet(pkt, written - c->seek_offset);
if (ret < 0)
return ret;
- memcpy(pkt->data, buf, written);
+ memcpy(pkt->data, buf + c->seek_offset, written - c->seek_offset);
+ pkt->pos = pos;
+ c->seek_offset = 0;
return 0;
}
+static int aa_read_seek(AVFormatContext *s,
+ int stream_index, int64_t timestamp, int flags)
+{
+ AADemuxContext *c = s->priv_data;
+ AVChapter *ch;
+ int64_t chapter_pos, chapter_start, chapter_size;
+ int chapter_idx = 0;
+
+ // find chapter containing seek timestamp
+ if (timestamp < 0)
+ timestamp = 0;
+
+ while (chapter_idx < s->nb_chapters && timestamp >= s->chapters[chapter_idx]->end) {
+ ++chapter_idx;
+ }
+
+ if (chapter_idx >= s->nb_chapters) {
+ chapter_idx = s->nb_chapters - 1;
+ if (chapter_idx < 0) return -1; // there is no chapter.
+ timestamp = s->chapters[chapter_idx]->end;
+ }
+
+ ch = s->chapters[chapter_idx];
+
+ // sync by clamping timestamp to nearest valid block position in its chapter
+ chapter_size = ch->end / TIMEPREC - ch->start / TIMEPREC;
+ chapter_pos = av_rescale_rnd((timestamp - ch->start) / TIMEPREC,
+ 1, c->codec_second_size,
+ (flags & AVSEEK_FLAG_BACKWARD) ? AV_ROUND_DOWN : AV_ROUND_UP)
+ * c->codec_second_size;
+ if (chapter_pos >= chapter_size)
+ chapter_pos = chapter_size;
+ chapter_start = c->content_start + (ch->start / TIMEPREC) + CHAPTER_HEADER_SIZE * (1 + chapter_idx);
+
+ // reinit read state
+ avio_seek(s->pb, chapter_start + chapter_pos, SEEK_SET);
+ c->current_codec_second_size = c->codec_second_size;
+ c->current_chapter_size = chapter_size - chapter_pos;
+ c->chapter_idx = 1 + chapter_idx;
+
+ // for unaligned frames, estimate offset of first frame in block (assume no padding)
+ if (s->streams[0]->codecpar->codec_id == AV_CODEC_ID_MP3) {
+ c->seek_offset = (MP3_FRAME_SIZE - chapter_pos % MP3_FRAME_SIZE) % MP3_FRAME_SIZE;
+ }
+
+ ff_update_cur_dts(s, s->streams[0], ch->start + (chapter_pos + c->seek_offset) * TIMEPREC);
+
+ return 1;
+}
+
static int aa_probe(AVProbeData *p)
{
uint8_t *buf = p->buf;
.read_probe = aa_probe,
.read_header = aa_read_header,
.read_packet = aa_read_packet,
+ .read_seek = aa_read_seek,
.read_close = aa_read_close,
- .flags = AVFMT_GENERIC_INDEX,
+ .flags = AVFMT_NO_BYTE_SEEK | AVFMT_NOGENSEARCH,
};
projects / ffmpeg / blobdiff