X-Git-Url: http://git.tuebingen.mpg.de/?a=blobdiff_plain;f=mp4.c;h=dbe2cf1c5f24d2846b4adb31e45c5fed396fc125;hb=f5846573f51d0210eb787862a1e759ec61eb766b;hp=08812c89b18345bb238ae117572ea9fc8c67b3d6;hpb=3b7939a8c294dc3ee103d99e6ff00e2800cf39f3;p=paraslash.git

diff --git a/mp4.c b/mp4.c
index 08812c89..dbe2cf1c 100644
--- a/mp4.c
+++ b/mp4.c
@@ -13,7 +13,23 @@
 #include "string.h"
 #include "mp4.h"
 
+/**
+ * The three states of the mp4 parser. The parser only loads the audio specific
+ * values and tables when it is in the second state.
+ */
+enum audio_track_state {
+	/** We haven't encountered an mp4a atom so far. */
+	ATS_INITIAL,
+	/** We have seen an mp4a atom but no subsequent trak atom yet. */
+	ATS_SEEN_MP4A,
+	/** A trak atom was seen *after* the mp4a atom. */
+	ATS_TRACK_CHANGE,
+};
+
 struct mp4_track {
+	/* determines which atoms we still need to parse. */
+	enum audio_track_state state;
+
 	/* mp4a */
 	uint16_t channel_count;
 	uint16_t sample_rate;
@@ -41,8 +57,6 @@ struct mp4_track {
 	uint64_t duration;
 };
 
-#define MAX_TRACKS 1024
-
 struct mp4 {
 	const struct mp4_callback *cb;
 
@@ -56,14 +70,7 @@ struct mp4 {
 	uint32_t udta_size;
 
 	uint8_t last_atom;
-	/* incremental track index while reading the file */
-	int32_t total_tracks;
-	/* track data */
-	struct mp4_track *track[MAX_TRACKS];
-	/* the first audio track found */
-	struct mp4_track *audio_track;
-
-	/* metadata */
+	struct mp4_track track;
 	struct mp4_metadata meta;
 };
 
@@ -90,7 +97,7 @@ static int read_int64(struct mp4 *f, uint64_t *result)
 	uint8_t data[8];
 	int ret = read_data(f, data, 8);
 
-	if (ret > 0 && result)
+	if (ret > 0)
 		*result = read_u64_be(data);
 	return ret;
 }
@@ -100,41 +107,21 @@ static int read_int32(struct mp4 *f, uint32_t *result)
 	uint8_t data[4];
 	int ret = read_data(f, data, 4);
 
-	if (ret > 0 && result)
+	if (ret > 0)
 		*result = read_u32_be(data);
 	return ret;
 }
 
-static int read_int24(struct mp4 *f, uint32_t *result)
-{
-	uint8_t data[3];
-	int ret = read_data(f, data, 3);
-
-	if (ret > 0 && result)
-		*result = read_u24_be(data);
-	return ret;
-}
-
 static int read_int16(struct mp4 *f, uint16_t *result)
 {
 	uint8_t data[2];
 	int ret = read_data(f, data, 2);
 
-	if (ret > 0 && result)
+	if (ret > 0)
 		*result = read_u16_be(data);
 	return ret;
 }
 
-static uint8_t read_int8(struct mp4 *f, uint8_t *result)
-{
-	uint8_t data[1];
-	int ret = read_data(f, data, 1);
-
-	if (ret > 0 && result)
-		*result = data[0];
-	return ret;
-}
-
 #define ATOM_ITEMS \
 	ATOM_ITEM(MOOV, 'm', 'o', 'o', 'v') \
 	ATOM_ITEM(TRAK, 't', 'r', 'a', 'k') \
@@ -201,8 +188,7 @@ static int atom_read_header(struct mp4 *f, uint8_t *atom_type,
 	} else {
 		if (header_size)
 			*header_size = 8;
-		if (atom_size)
-			*atom_size = size;
+		*atom_size = size;
 	}
 	*atom_type = atom_name_to_type(atom_header + 4);
 	return 1;
@@ -218,21 +204,20 @@ static void set_position(struct mp4 *f, off_t position)
 	f->cb->seek(f->cb->user_data, position, SEEK_SET);
 }
 
+static void skip_bytes(struct mp4 *f, off_t num_skip)
+{
+	f->cb->seek(f->cb->user_data, num_skip, SEEK_CUR);
+}
+
 static int read_stsz(struct mp4 *f)
 {
 	int ret;
 	int32_t i;
-	struct mp4_track *t;
+	struct mp4_track *t = &f->track;
 
-	if (f->total_tracks == 0)
-		return -1;
-	t = f->track[f->total_tracks - 1];
-	ret = read_int8(f, NULL); /* version */
-	if (ret <= 0)
-		return ret;
-	ret = read_int24(f, NULL); /* flags */
-	if (ret <= 0)
-		return ret;
+	if (t->state != ATS_SEEN_MP4A || t->stsz_table)
+		return 1;
+	skip_bytes(f, 4); /* version (1), flags (3) */
 	ret = read_int32(f, &t->stsz_sample_size);
 	if (ret <= 0)
 		return ret;
@@ -254,19 +239,11 @@ static int read_stts(struct mp4 *f)
 {
 	int ret;
 	int32_t i;
-	struct mp4_track *t;
+	struct mp4_track *t = &f->track;
 
-	if (f->total_tracks == 0)
-		return -1;
-	t = f->track[f->total_tracks - 1];
-	if (t->stts_entry_count)
-		return 0;
-	ret = read_int8(f, NULL); /* version */
-	if (ret <= 0)
-		return ret;
-	ret = read_int24(f, NULL); /* flags */
-	if (ret <= 0)
-		return ret;
+	if (t->state != ATS_SEEN_MP4A || t->stts_sample_count)
+		return 1;
+	skip_bytes(f, 4); /* version (1), flags (3) */
 	ret = read_int32(f, &t->stts_entry_count);
 	if (ret <= 0)
 		return ret;
@@ -276,9 +253,7 @@ static int read_stts(struct mp4 *f)
 		ret = read_int32(f, &t->stts_sample_count[i]);
 		if (ret <= 0)
 			return ret;
-		ret = read_int32(f, NULL); /* sample delta */
-		if (ret <= 0)
-			return ret;
+		skip_bytes(f, 4); /* sample delta */
 	}
 	return 1;
 }
@@ -287,18 +262,13 @@ static int read_stsc(struct mp4 *f)
 {
 	int ret;
 	int32_t i;
-	struct mp4_track *t;
-
-	if (f->total_tracks == 0)
-		return -1;
-	t = f->track[f->total_tracks - 1];
+	struct mp4_track *t = &f->track;
 
-	ret = read_int8(f, NULL); /* version */
-	if (ret <= 0)
-		return ret;
-	ret = read_int24(f, NULL); /* flags */
-	if (ret <= 0)
-		return ret;
+	if (t->state != ATS_SEEN_MP4A)
+		return 1;
+	if (t->stsc_first_chunk || t->stsc_samples_per_chunk)
+		return 1;
+	skip_bytes(f, 4); /* version (1), flags (3) */
 	ret = read_int32(f, &t->stsc_entry_count);
 	if (ret <= 0)
 		return ret;
@@ -312,9 +282,7 @@ static int read_stsc(struct mp4 *f)
 		ret = read_int32(f, &t->stsc_samples_per_chunk[i]);
 		if (ret <= 0)
 			return ret;
-		ret = read_int32(f, NULL); /* sample desc index */
-		if (ret <= 0)
-			return ret;
+		skip_bytes(f, 4); /* sample desc index */
 	}
 	return 1;
 }
@@ -323,18 +291,11 @@ static int read_stco(struct mp4 *f)
 {
 	int ret;
 	int32_t i;
-	struct mp4_track *t;
+	struct mp4_track *t = &f->track;
 
-	if (f->total_tracks == 0)
-		return -1;
-	t = f->track[f->total_tracks - 1];
-
-	ret = read_int8(f, NULL); /* version */
-	if (ret <= 0)
-		return ret;
-	ret = read_int24(f, NULL); /* flags */
-	if (ret <= 0)
-		return ret;
+	if (t->state != ATS_SEEN_MP4A || t->stco_chunk_offset)
+		return 1;
+	skip_bytes(f, 4); /* version (1), flags (3) */
 	ret = read_int32(f, &t->stco_entry_count);
 	if (ret <= 0)
 		return ret;
@@ -348,60 +309,14 @@ static int read_stco(struct mp4 *f)
 	return 1;
 }
 
-static int read_mp4a(struct mp4 *f)
-{
-	int ret;
-	int32_t i;
-	struct mp4_track *t;
-
-	if (f->total_tracks == 0)
-		return -1;
-	t = f->track[f->total_tracks - 1];
-
-	for (i = 0; i < 6; i++) {
-		ret = read_int8(f, NULL); /* reserved */
-		if (ret <= 0)
-			return ret;
-	}
-	ret = read_int16(f, NULL); /* data_reference_index */
-	if (ret <= 0)
-		return ret;
-	ret = read_int32(f, NULL); /* reserved */
-	if (ret <= 0)
-		return ret;
-	ret = read_int32(f, NULL); /* reserved */
-	if (ret <= 0)
-		return ret;
-	ret = read_int16(f, &t->channel_count);
-	if (ret <= 0)
-		return ret;
-	ret = read_int16(f, NULL);
-	if (ret <= 0)
-		return ret;
-	ret = read_int16(f, NULL);
-	if (ret <= 0)
-		return ret;
-	ret = read_int16(f, NULL);
-	if (ret <= 0)
-		return ret;
-	return read_int16(f, &t->sample_rate);
-}
-
 static int read_stsd(struct mp4 *f)
 {
 	int ret;
 	uint32_t i, entry_count;
-	struct mp4_track *t;
 
-	if (f->total_tracks == 0)
-		return -1;
-	t = f->track[f->total_tracks - 1];
-	ret = read_int8(f, NULL); /* version */
-	if (ret <= 0)
-		return ret;
-	ret = read_int24(f, NULL); /* flags */
-	if (ret <= 0)
-		return ret;
+	if (f->track.state != ATS_INITIAL)
+		return 1;
+	skip_bytes(f, 4); /* version (1), flags (3) */
 	ret = read_int32(f, &entry_count);
 	if (ret <= 0)
 		return ret;
@@ -413,9 +328,17 @@ static int read_stsd(struct mp4 *f)
 		if (ret <= 0)
 			return ret;
 		skip += size;
-		if (!f->audio_track && atom_type == ATOM_MP4A) {
-			f->audio_track = t;
-			read_mp4a(f);
+		if (atom_type == ATOM_MP4A) {
+			f->track.state = ATS_SEEN_MP4A;
+			/* reserved (6), data reference index (2), reserved (8) */
+			skip_bytes(f, 16);
+			ret = read_int16(f, &f->track.channel_count);
+			if (ret <= 0)
+				return ret;
+			skip_bytes(f, 6);
+			ret = read_int16(f, &f->track.sample_rate);
+			if (ret <= 0)
+				return ret;
 		}
 		set_position(f, skip);
 	}
@@ -456,15 +379,7 @@ static int parse_tag(struct mp4 *f, uint8_t parent, int32_t size)
 		destpos = get_position(f) + subsize - header_size;
 		if (atom_type != ATOM_DATA)
 			continue;
-		ret = read_int8(f, NULL); /* version */
-		if (ret <= 0)
-			goto fail;
-		ret = read_int24(f, NULL); /* flags */
-		if (ret <= 0)
-			goto fail;
-		ret = read_int32(f, NULL); /* reserved */
-		if (ret <= 0)
-			goto fail;
+		skip_bytes(f, 8); /* version (1), flags (3), reserved (4) */
 		ret = -ERRNO_TO_PARA_ERROR(EINVAL);
 		if (subsize < header_size + 8 || subsize > UINT_MAX)
 			goto fail;
@@ -495,22 +410,15 @@ static int read_mdhd(struct mp4 *f)
 {
 	int ret;
 	uint32_t version;
-	struct mp4_track *t;
-
-	if (f->total_tracks == 0)
-		return -1;
-	t = f->track[f->total_tracks - 1];
+	struct mp4_track *t = &f->track;
 
+	if (t->state != ATS_INITIAL)
+		return 1;
 	ret = read_int32(f, &version);
 	if (ret <= 0)
 		return ret;
 	if (version == 1) {
-		ret = read_int64(f, NULL); /* creation-time */
-		if (ret <= 0)
-			return ret;
-		ret = read_int64(f, NULL); /* modification-time */
-		if (ret <= 0)
-			return ret;
+		skip_bytes(f, 16); /* creation time (8), modification time (8) */
 		ret = read_int32(f, &t->time_scale);
 		if (ret <= 0)
 			return ret;
@@ -520,12 +428,7 @@ static int read_mdhd(struct mp4 *f)
 	} else { //version == 0
 		uint32_t temp;
 
-		ret = read_int32(f, NULL); /* creation-time */
-		if (ret <= 0)
-			return ret;
-		ret = read_int32(f, NULL); /* modification-time */
-		if (ret <= 0)
-			return ret;
+		skip_bytes(f, 8); /* creation time (4), modification time (4) */
 		ret = read_int32(f, &t->time_scale);
 		if (ret <= 0)
 			return ret;
@@ -535,12 +438,7 @@ static int read_mdhd(struct mp4 *f)
 		t->duration = (temp == (uint32_t) (-1))?
 			(uint64_t) (-1) : (uint64_t) (temp);
 	}
-	ret = read_int16(f, NULL);
-	if (ret <= 0)
-		return ret;
-	ret = read_int16(f, NULL);
-	if (ret <= 0)
-		return ret;
+	skip_bytes(f, 4);
 	return 1;
 }
 
@@ -580,12 +478,7 @@ static int32_t read_meta(struct mp4 *f, uint64_t size)
 	uint8_t atom_type;
 	uint8_t header_size = 0;
 
-	ret = read_int8(f, NULL); /* version */
-	if (ret <= 0)
-		return ret;
-	ret = read_int24(f, NULL); /* flags */
-	if (ret <= 0)
-		return ret;
+	skip_bytes(f, 4); /* version (1), flags (3) */
 	while (sumsize < (size - (header_size + 4))) {
 		ret = atom_read_header(f, &atom_type, &header_size, &subsize);
 		if (ret <= 0)
@@ -647,13 +540,11 @@ static int parse_sub_atoms(struct mp4 *f, uint64_t total_size, bool meta_only)
 		if (size == 0)
 			return -1;
 		dest = get_position(f) + size - header_size;
-		if (atom_type == ATOM_TRAK) {
-			if (f->total_tracks >= MAX_TRACKS)
-				return -1;
-			f->total_tracks++;
-			f->track[f->total_tracks - 1] = para_calloc(
-				sizeof(struct mp4_track));
-		} else if (atom_type == ATOM_UDTA) {
+		if (atom_type == ATOM_TRAK && f->track.state == ATS_SEEN_MP4A) {
+			f->track.state = ATS_TRACK_CHANGE;
+			continue;
+		}
+		if (atom_type == ATOM_UDTA) {
 			f->udta_offset = get_position(f) - header_size;
 			f->udta_size = size;
 		}
@@ -705,7 +596,7 @@ static int open_file(const struct mp4_callback *cb, bool meta_only, struct mp4 *
 		goto fail;
 	}
 	ret = -E_MP4_TRACK;
-	if (!f->audio_track)
+	if (f->track.channel_count == 0)
 		goto fail;
 	*result = f;
 	return 1;
@@ -724,16 +615,11 @@ void mp4_close(struct mp4 *f)
 {
 	int32_t i;
 
-	for (i = 0; i < f->total_tracks; i++) {
-		if (f->track[i]) {
-			free(f->track[i]->stsz_table);
-			free(f->track[i]->stts_sample_count);
-			free(f->track[i]->stsc_first_chunk);
-			free(f->track[i]->stsc_samples_per_chunk);
-			free(f->track[i]->stco_chunk_offset);
-			free(f->track[i]);
-		}
-	}
+	free(f->track.stsz_table);
+	free(f->track.stts_sample_count);
+	free(f->track.stsc_first_chunk);
+	free(f->track.stsc_samples_per_chunk);
+	free(f->track.stco_chunk_offset);
 	for (i = 0; i < f->meta.count; i++) {
 		free(f->meta.tags[i].item);
 		free(f->meta.tags[i].value);
@@ -745,7 +631,7 @@ void mp4_close(struct mp4 *f)
 static int32_t chunk_of_sample(const struct mp4 *f, int32_t sample,
 		int32_t *chunk)
 {
-	const struct mp4_track *t = f->audio_track;
+	const struct mp4_track *t = &f->track;
 	uint32_t *fc = t->stsc_first_chunk, *spc = t->stsc_samples_per_chunk;
 	int32_t chunk1, chunk1samples, n, total, i;
 
@@ -770,7 +656,7 @@ static int32_t chunk_of_sample(const struct mp4 *f, int32_t sample,
  */
 uint64_t mp4_get_duration(const struct mp4 *f)
 {
-	const struct mp4_track *t = f->audio_track;
+	const struct mp4_track *t = &f->track;
 
 	if (t->time_scale == 0)
 		return 0;
@@ -779,7 +665,7 @@ uint64_t mp4_get_duration(const struct mp4 *f)
 
 int mp4_set_sample_position(struct mp4 *f, int32_t sample)
 {
-	const struct mp4_track *t = f->audio_track;
+	const struct mp4_track *t = &f->track;
 	int32_t offset, chunk, chunk_sample;
 	uint32_t n, srs; /* sample range size */
 
@@ -804,7 +690,7 @@ int mp4_set_sample_position(struct mp4 *f, int32_t sample)
 
 int32_t mp4_get_sample_size(const struct mp4 *f, int sample)
 {
-	const struct mp4_track *t = f->audio_track;
+	const struct mp4_track *t = &f->track;
 
 	if (t->stsz_sample_size != 0)
 		return t->stsz_sample_size;
@@ -813,17 +699,17 @@ int32_t mp4_get_sample_size(const struct mp4 *f, int sample)
 
 uint32_t mp4_get_sample_rate(const struct mp4 *f)
 {
-	return f->audio_track->sample_rate;
+	return f->track.sample_rate;
 }
 
 uint32_t mp4_get_channel_count(const struct mp4 *f)
 {
-	return f->audio_track->channel_count;
+	return f->track.channel_count;
 }
 
 int32_t mp4_num_samples(const struct mp4 *f)
 {
-	const struct mp4_track *t = f->audio_track;
+	const struct mp4_track *t = &f->track;
 	int32_t i;
 	int32_t total = 0;