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avformat/cafenc: Simplify writing pakt box

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Assemble it already in caf_write_packet(). This has the advantage
of reducing the amount of buffers used; it also allows to avoid
a seek when writing the trailer and avoids function call overhead
(for the avio_w8(); it also reduces codesize).

Reviewed-by: James Almer <jamrial@gmail.com>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
This commit is contained in:
Andreas Rheinhardt
2026-01-30 14:25:00 +01:00
parent 38230db7b9
commit 96475bfa21
1 changed files with 34 additions and 64 deletions
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98
libavformat/cafenc.c
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@@ -19,6 +19,8 @@
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <stdint.h>
#include "avformat.h"
#include "caf.h"
#include "isom.h"
@@ -36,10 +38,9 @@ typedef struct {
int64_t packets;
uint32_t frame_size;
uint32_t *byte_size_buffer;
uint32_t *frame_size_buffer;
unsigned byte_size_buffer_sz;
unsigned frame_size_buffer_sz;
uint8_t *pakt_buf;
unsigned pakt_buf_size;
unsigned pakt_buf_alloc_size;
} CAFContext;
static uint32_t codec_flags(enum AVCodecID codec_id) {
@@ -236,39 +237,39 @@ static int caf_write_header(AVFormatContext *s)
return 0;
}
static uint8_t *put_variable_length_num(uint8_t *buf, uint32_t num)
{
for (int j = 4; j > 0; j--) {
unsigned top = num >> j * 7;
if (top)
*(buf++) = top | 128;
}
*(buf++) = num & 127;
return buf;
}
static int caf_write_packet(AVFormatContext *s, AVPacket *pkt)
{
CAFContext *caf = s->priv_data;
AVStream *const st = s->streams[0];
if (!st->codecpar->block_align || !caf->frame_size) {
void *pkt_sizes;
unsigned alloc_size = caf->packets + 1;
#if SIZE_MAX - 10 < UINT_MAX
if (caf->pakt_buf_size > SIZE_MAX - 10)
return AVERROR(ERANGE);
#endif
uint8_t *pakt_buf = av_fast_realloc(caf->pakt_buf, &caf->pakt_buf_alloc_size,
caf->pakt_buf_size + (size_t)10);
if (!pakt_buf)
return AVERROR(ENOMEM);
caf->pakt_buf = pakt_buf;
pakt_buf += caf->pakt_buf_size;
if (!st->codecpar->block_align) {
if (UINT_MAX / sizeof(*caf->byte_size_buffer) < alloc_size)
return AVERROR(ERANGE);
pkt_sizes = av_fast_realloc(caf->byte_size_buffer,
&caf->byte_size_buffer_sz,
alloc_size * sizeof(*caf->byte_size_buffer));
if (!pkt_sizes)
return AVERROR(ENOMEM);
caf->byte_size_buffer = pkt_sizes;
caf->byte_size_buffer[caf->packets] = pkt->size;
}
if (!caf->frame_size) {
if (UINT_MAX / sizeof(*caf->frame_size_buffer) < alloc_size)
return AVERROR(ERANGE);
pkt_sizes = av_fast_realloc(caf->frame_size_buffer,
&caf->frame_size_buffer_sz,
alloc_size * sizeof(*caf->frame_size_buffer));
if (!pkt_sizes)
return AVERROR(ENOMEM);
caf->frame_size_buffer = pkt_sizes;
caf->frame_size_buffer[caf->packets] = pkt->duration;
}
if (!st->codecpar->block_align)
pakt_buf = put_variable_length_num(pakt_buf, pkt->size);
if (!caf->frame_size)
pakt_buf = put_variable_length_num(pakt_buf, pkt->duration);
caf->pakt_buf_size = pakt_buf - caf->pakt_buf;
}
caf->packets++;
caf->total_duration += pkt->duration;
@@ -295,47 +296,17 @@ static int caf_write_trailer(AVFormatContext *s)
avio_wb64(pb, file_size - caf->data - 8);
if (!par->block_align || !caf->frame_size || par->initial_padding || remainder_frames) {
int64_t size = 24;
valid_frames -= par->initial_padding;
valid_frames -= remainder_frames;
avio_seek(pb, file_size, SEEK_SET);
ffio_wfourcc(pb, "pakt");
avio_wb64(pb, 0); // size, to be replaced
avio_wb64(pb, 24ULL + caf->pakt_buf_size); // size
avio_wb64(pb, packets); ///< mNumberPackets
avio_wb64(pb, valid_frames); ///< mNumberValidFrames
avio_wb32(pb, par->initial_padding); ///< mPrimingFrames
avio_wb32(pb, remainder_frames); ///< mRemainderFrames
for (int i = 0; i < packets; i++) {
if (!par->block_align) {
for (int j = 4; j > 0; j--) {
unsigned top = caf->byte_size_buffer[i] >> j * 7;
if (top) {
avio_w8(pb, 128 | (uint8_t)top);
size++;
}
}
avio_w8(pb, caf->byte_size_buffer[i] & 127);
size++;
}
if (!caf->frame_size) {
for (int j = 4; j > 0; j--) {
unsigned top = caf->frame_size_buffer[i] >> j * 7;
if (top) {
avio_w8(pb, 128 | (uint8_t)top);
size++;
}
}
avio_w8(pb, caf->frame_size_buffer[i] & 127);
size++;
}
}
int64_t end = avio_tell(pb);
avio_seek(pb, file_size + 4, SEEK_SET);
avio_wb64(pb, size);
avio_seek(pb, end, SEEK_SET);
avio_write(pb, caf->pakt_buf, caf->pakt_buf_size);
}
}
@@ -346,8 +317,7 @@ static void caf_write_deinit(AVFormatContext *s)
{
CAFContext *caf = s->priv_data;
av_freep(&caf->byte_size_buffer);
av_freep(&caf->frame_size_buffer);
av_freep(&caf->pakt_buf);
}
const FFOutputFormat ff_caf_muxer = {