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avformat/movenc: factorize data shifting

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And move data shift function from movenc to utils.

Signed-off-by: Marton Balint <cus@passwd.hu>
This commit is contained in:
Marton Balint 2021-12-11 16:27:28 +01:00
parent 4be85c9331
commit 76e062322c
3 changed files with 65 additions and 53 deletions
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7
libavformat/internal.h
View File

@ -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 */

55
libavformat/movenc.c
View File

@ -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)

56
libavformat/utils.c
View File

@ -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;
}