[FFmpeg-devel] [PATCH 2/5] avformat/movenc: factorize data shifting
Marton Balint
cus at passwd.hu
Mon Dec 27 02:26:10 EET 2021
And move data shift function from movenc to utils.
Signed-off-by: Marton Balint <cus at passwd.hu>
---
libavformat/internal.h | 7 ++++++
libavformat/movenc.c | 55 ++---------------------------------------
libavformat/utils.c | 56 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 65 insertions(+), 53 deletions(-)
diff --git a/libavformat/internal.h b/libavformat/internal.h
index 2ba795d669..63235ce5cf 100644
--- a/libavformat/internal.h
+++ b/libavformat/internal.h
@@ -1019,4 +1019,11 @@ void ff_format_set_url(AVFormatContext *s, char *url);
void avpriv_register_devices(const AVOutputFormat * const o[], const AVInputFormat * const i[]);
+/**
+ * Make shift_size amount of space at read_start by shifting data in the output
+ * at read_start until the current IO position. The underlying IO context must
+ * be seekable.
+ */
+int ff_format_shift_data(AVFormatContext *s, int64_t read_start, int shift_size);
+
#endif /* AVFORMAT_INTERNAL_H */
diff --git a/libavformat/movenc.c b/libavformat/movenc.c
index 0f912dd012..40ad4f8642 100644
--- a/libavformat/movenc.c
+++ b/libavformat/movenc.c
@@ -7150,13 +7150,8 @@ static int compute_sidx_size(AVFormatContext *s)
static int shift_data(AVFormatContext *s)
{
- int ret = 0, moov_size;
+ int moov_size;
MOVMuxContext *mov = s->priv_data;
- int64_t pos, pos_end;
- uint8_t *buf, *read_buf[2];
- int read_buf_id = 0;
- int read_size[2];
- AVIOContext *read_pb;
if (mov->flags & FF_MOV_FLAG_FRAGMENT)
moov_size = compute_sidx_size(s);
@@ -7165,53 +7160,7 @@ static int shift_data(AVFormatContext *s)
if (moov_size < 0)
return moov_size;
- buf = av_malloc(moov_size * 2);
- if (!buf)
- return AVERROR(ENOMEM);
- read_buf[0] = buf;
- read_buf[1] = buf + moov_size;
-
- /* Shift the data: the AVIO context of the output can only be used for
- * writing, so we re-open the same output, but for reading. It also avoids
- * a read/seek/write/seek back and forth. */
- avio_flush(s->pb);
- ret = s->io_open(s, &read_pb, s->url, AVIO_FLAG_READ, NULL);
- if (ret < 0) {
- av_log(s, AV_LOG_ERROR, "Unable to re-open %s output file for "
- "the second pass (faststart)\n", s->url);
- goto end;
- }
-
- /* mark the end of the shift to up to the last data we wrote, and get ready
- * for writing */
- pos_end = avio_tell(s->pb);
- avio_seek(s->pb, mov->reserved_header_pos + moov_size, SEEK_SET);
-
- /* start reading at where the new moov will be placed */
- avio_seek(read_pb, mov->reserved_header_pos, SEEK_SET);
- pos = avio_tell(read_pb);
-
-#define READ_BLOCK do { \
- read_size[read_buf_id] = avio_read(read_pb, read_buf[read_buf_id], moov_size); \
- read_buf_id ^= 1; \
-} while (0)
-
- /* shift data by chunk of at most moov_size */
- READ_BLOCK;
- do {
- int n;
- READ_BLOCK;
- n = read_size[read_buf_id];
- if (n <= 0)
- break;
- avio_write(s->pb, read_buf[read_buf_id], n);
- pos += n;
- } while (pos < pos_end);
- ff_format_io_close(s, &read_pb);
-
-end:
- av_free(buf);
- return ret;
+ return ff_format_shift_data(s, mov->reserved_header_pos, moov_size);
}
static int mov_write_trailer(AVFormatContext *s)
diff --git a/libavformat/utils.c b/libavformat/utils.c
index 332ba534d2..a78797ef57 100644
--- a/libavformat/utils.c
+++ b/libavformat/utils.c
@@ -2035,3 +2035,59 @@ const char *av_disposition_to_string(int disposition)
return NULL;
}
+
+int ff_format_shift_data(AVFormatContext *s, int64_t read_start, int shift_size)
+{
+ int ret;
+ int64_t pos, pos_end;
+ uint8_t *buf, *read_buf[2];
+ int read_buf_id = 0;
+ int read_size[2];
+ AVIOContext *read_pb;
+
+ buf = av_malloc_array(shift_size, 2);
+ if (!buf)
+ return AVERROR(ENOMEM);
+ read_buf[0] = buf;
+ read_buf[1] = buf + shift_size;
+
+ /* Shift the data: the AVIO context of the output can only be used for
+ * writing, so we re-open the same output, but for reading. It also avoids
+ * a read/seek/write/seek back and forth. */
+ avio_flush(s->pb);
+ ret = s->io_open(s, &read_pb, s->url, AVIO_FLAG_READ, NULL);
+ if (ret < 0) {
+ av_log(s, AV_LOG_ERROR, "Unable to re-open %s output file for shifting data\n", s->url);
+ goto end;
+ }
+
+ /* mark the end of the shift to up to the last data we wrote, and get ready
+ * for writing */
+ pos_end = avio_tell(s->pb);
+ avio_seek(s->pb, read_start + shift_size, SEEK_SET);
+
+ avio_seek(read_pb, read_start, SEEK_SET);
+ pos = avio_tell(read_pb);
+
+#define READ_BLOCK do { \
+ read_size[read_buf_id] = avio_read(read_pb, read_buf[read_buf_id], shift_size); \
+ read_buf_id ^= 1; \
+} while (0)
+
+ /* shift data by chunk of at most shift_size */
+ READ_BLOCK;
+ do {
+ int n;
+ READ_BLOCK;
+ n = read_size[read_buf_id];
+ if (n <= 0)
+ break;
+ avio_write(s->pb, read_buf[read_buf_id], n);
+ pos += n;
+ } while (pos < pos_end);
+ ff_format_io_close(s, &read_pb);
+
+end:
+ av_free(buf);
+ return ret;
+}
--
2.31.1
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