[FFmpeg-cvslog] mpegts: Replace the MP4 descriptor parser with a recursive parser.
Alex Converse
git at videolan.org
Sat Oct 29 02:31:42 CEST 2011
ffmpeg | branch: master | Alex Converse <alex.converse at gmail.com> | Wed Oct 5 11:04:42 2011 -0700| [fec2836483c15f169c3f8be39347978f1698ae8d] | committer: Alex Converse
mpegts: Replace the MP4 descriptor parser with a recursive parser.
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=fec2836483c15f169c3f8be39347978f1698ae8d
---
libavformat/mpegts.c | 174 ++++++++++++++++++++++++++++++++++++++++----------
1 files changed, 140 insertions(+), 34 deletions(-)
diff --git a/libavformat/mpegts.c b/libavformat/mpegts.c
index 0284c39..3703d2c 100644
--- a/libavformat/mpegts.c
+++ b/libavformat/mpegts.c
@@ -870,38 +870,147 @@ static PESContext *add_pes_stream(MpegTSContext *ts, int pid, int pcr_pid)
return pes;
}
-static int mp4_read_iods(AVFormatContext *s, const uint8_t *buf, unsigned size,
- int *es_id, uint8_t **dec_config_descr,
- int *dec_config_descr_size)
-{
+#define MAX_LEVEL 4
+typedef struct {
+ AVFormatContext *s;
AVIOContext pb;
+ Mp4Descr *descr;
+ Mp4Descr *active_descr;
+ int descr_count;
+ int max_descr_count;
+ int level;
+} MP4DescrParseContext;
+
+static int init_MP4DescrParseContext(
+ MP4DescrParseContext *d, AVFormatContext *s, const uint8_t *buf,
+ unsigned size, Mp4Descr *descr, int max_descr_count)
+{
+ int ret;
+ if (size > (1<<30))
+ return AVERROR_INVALIDDATA;
+
+ if ((ret = ffio_init_context(&d->pb, (unsigned char*)buf, size, 0,
+ NULL, NULL, NULL, NULL)) < 0)
+ return ret;
+
+ d->s = s;
+ d->level = 0;
+ d->descr_count = 0;
+ d->descr = descr;
+ d->active_descr = NULL;
+ d->max_descr_count = max_descr_count;
+
+ return 0;
+}
+
+static void update_offsets(AVIOContext *pb, int64_t *off, int *len) {
+ int64_t new_off = avio_tell(pb);
+ (*len) -= new_off - *off;
+ *off = new_off;
+}
+
+static int parse_mp4_descr(MP4DescrParseContext *d, int64_t off, int len,
+ int target_tag);
+
+static int parse_mp4_descr_arr(MP4DescrParseContext *d, int64_t off, int len)
+{
+ while (len > 0) {
+ if (parse_mp4_descr(d, off, len, 0) < 0)
+ return -1;
+ update_offsets(&d->pb, &off, &len);
+ }
+ return 0;
+}
+
+static int parse_MP4IODescrTag(MP4DescrParseContext *d, int64_t off, int len)
+{
+ avio_rb16(&d->pb); // ID
+ avio_r8(&d->pb);
+ avio_r8(&d->pb);
+ avio_r8(&d->pb);
+ avio_r8(&d->pb);
+ avio_r8(&d->pb);
+ update_offsets(&d->pb, &off, &len);
+ return parse_mp4_descr_arr(d, off, len);
+}
+
+static int parse_MP4ESDescrTag(MP4DescrParseContext *d, int64_t off, int len)
+{
+ int es_id = 0;
+ if (d->descr_count >= d->max_descr_count)
+ return -1;
+ ff_mp4_parse_es_descr(&d->pb, &es_id);
+ d->active_descr = d->descr + (d->descr_count++);
+
+ d->active_descr->es_id = es_id;
+ update_offsets(&d->pb, &off, &len);
+ parse_mp4_descr(d, off, len, MP4DecConfigDescrTag);
+ //SLConfigDescriptor
+ d->active_descr = NULL;
+ return 0;
+}
+
+static int parse_MP4DecConfigDescrTag(MP4DescrParseContext *d, int64_t off, int len)
+{
+ Mp4Descr *descr = d->active_descr;
+ if (!descr)
+ return -1;
+ d->active_descr->dec_config_descr = av_malloc(len);
+ if (!descr->dec_config_descr)
+ return AVERROR(ENOMEM);
+ descr->dec_config_descr_len = len;
+ avio_read(&d->pb, descr->dec_config_descr, len);
+ return 0;
+}
+
+static int parse_mp4_descr(MP4DescrParseContext *d, int64_t off, int len,
+ int target_tag) {
int tag;
- unsigned len;
-
- ffio_init_context(&pb, buf, size, 0, NULL, NULL, NULL, NULL);
-
- len = ff_mp4_read_descr(s, &pb, &tag);
- if (tag == MP4IODescrTag) {
- avio_rb16(&pb); // ID
- avio_r8(&pb);
- avio_r8(&pb);
- avio_r8(&pb);
- avio_r8(&pb);
- avio_r8(&pb);
- len = ff_mp4_read_descr(s, &pb, &tag);
- if (tag == MP4ESDescrTag) {
- ff_mp4_parse_es_descr(&pb, es_id);
- av_dlog(s, "ES_ID %#x\n", *es_id);
- len = ff_mp4_read_descr(s, &pb, &tag);
- if (tag == MP4DecConfigDescrTag) {
- *dec_config_descr = av_malloc(len);
- if (!*dec_config_descr)
- return AVERROR(ENOMEM);
- *dec_config_descr_size = len;
- avio_read(&pb, *dec_config_descr, len);
- }
- }
+ int len1 = ff_mp4_read_descr(d->s, &d->pb, &tag);
+ update_offsets(&d->pb, &off, &len);
+ if (len < 0 || len1 > len || len1 <= 0) {
+ av_log(d->s, AV_LOG_ERROR, "Tag %x length violation new length %d bytes remaining %d\n", tag, len1, len);
+ return -1;
+ }
+
+ if (d->level++ >= MAX_LEVEL) {
+ av_log(d->s, AV_LOG_ERROR, "Maximum MP4 descriptor level exceeded\n");
+ goto done;
+ }
+
+ if (target_tag && tag != target_tag) {
+ av_log(d->s, AV_LOG_ERROR, "Found tag %x expected %x\n", tag, target_tag);
+ goto done;
+ }
+
+ switch (tag) {
+ case MP4IODescrTag:
+ parse_MP4IODescrTag(d, off, len1);
+ break;
+ case MP4ESDescrTag:
+ parse_MP4ESDescrTag(d, off, len1);
+ break;
+ case MP4DecConfigDescrTag:
+ parse_MP4DecConfigDescrTag(d, off, len1);
+ break;
}
+
+done:
+ d->level--;
+ avio_seek(&d->pb, off + len1, SEEK_SET);
+ return 0;
+}
+
+static int mp4_read_iods(AVFormatContext *s, const uint8_t *buf, unsigned size,
+ Mp4Descr *descr, int *descr_count, int max_descr_count)
+{
+ MP4DescrParseContext d;
+ if (init_MP4DescrParseContext(&d, s, buf, size, descr, max_descr_count) < 0)
+ return -1;
+
+ parse_mp4_descr(&d, avio_tell(&d.pb), size, MP4IODescrTag);
+
+ *descr_count = d.descr_count;
return 0;
}
@@ -1080,11 +1189,8 @@ static void pmt_cb(MpegTSFilter *filter, const uint8_t *section, int section_len
get8(&p, p_end); // scope
get8(&p, p_end); // label
len -= 2;
- if (mp4_descr_count < MAX_MP4_DESCR_COUNT) {
- mp4_descr_count++;
- mp4_read_iods(ts->stream, p, len, &mp4_descr->es_id,
- &mp4_descr->dec_config_descr, &mp4_descr->dec_config_descr_len);
- }
+ mp4_read_iods(ts->stream, p, len, mp4_descr + mp4_descr_count,
+ &mp4_descr_count, MAX_MP4_DESCR_COUNT);
} else if (tag == 0x05 && len >= 4) { // registration descriptor
prog_reg_desc = bytestream_get_le32(&p);
len -= 4;
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