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avcodec/mpeg4_unpack_bframes: cache input packets directly 

Avoids unnecessary allocs+copies and makes the code slightly simpler.

Signed-off-by: James Almer <jamrial@gmail.com>
This commit is contained in:
James Almer 2018-03-20 21:59:10 -03:00
parent d8e92a89ed
commit bd90a2ec04
1 changed files with 19 additions and 37 deletions
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56
libavcodec/mpeg4_unpack_bframes_bsf.c
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@ -24,8 +24,7 @@
#include "mpeg4video.h"
typedef struct UnpackBFramesBSFContext {
uint8_t *b_frame_buf;
int b_frame_buf_size;
AVPacket *b_frame;
} UnpackBFramesBSFContext;
/* search next start code */
@ -71,18 +70,6 @@ static void scan_buffer(const uint8_t *buf, int buf_size,
}
}
/* allocate new buffer and copy size bytes from src */
static uint8_t *create_new_buffer(const uint8_t *src, int size) {
uint8_t *dst = av_malloc(size + AV_INPUT_BUFFER_PADDING_SIZE);
if (dst) {
memcpy(dst, src, size);
memset(dst + size, 0, AV_INPUT_BUFFER_PADDING_SIZE);
}
return dst;
}
static int mpeg4_unpack_bframes_filter(AVBSFContext *ctx, AVPacket *out)
{
UnpackBFramesBSFContext *s = ctx->priv_data;
@ -97,20 +84,18 @@ static int mpeg4_unpack_bframes_filter(AVBSFContext *ctx, AVPacket *out)
av_log(ctx, AV_LOG_DEBUG, "Found %d VOP startcode(s) in this packet.\n", nb_vop);
if (pos_vop2 >= 0) {
if (s->b_frame_buf) {
if (s->b_frame->data) {
av_log(ctx, AV_LOG_WARNING,
"Missing one N-VOP packet, discarding one B-frame.\n");
av_freep(&s->b_frame_buf);
s->b_frame_buf_size = 0;
av_packet_unref(s->b_frame);
}
/* store the packed B-frame in the BSFContext */
s->b_frame_buf_size = in->size - pos_vop2;
s->b_frame_buf = create_new_buffer(in->data + pos_vop2, s->b_frame_buf_size);
if (!s->b_frame_buf) {
s->b_frame_buf_size = 0;
ret = AVERROR(ENOMEM);
ret = av_packet_ref(s->b_frame, in);
if (ret < 0) {
goto fail;
}
s->b_frame->size -= pos_vop2;
s->b_frame->data += pos_vop2;
}
if (nb_vop > 2) {
@ -118,31 +103,22 @@ static int mpeg4_unpack_bframes_filter(AVBSFContext *ctx, AVPacket *out)
"Found %d VOP headers in one packet, only unpacking one.\n", nb_vop);
}
if (nb_vop == 1 && s->b_frame_buf) {
if (nb_vop == 1 && s->b_frame->data) {
/* use frame from BSFContext */
av_packet_move_ref(out, s->b_frame);
/* use properties from current input packet */
ret = av_packet_copy_props(out, in);
if (ret < 0) {
goto fail;
}
ret = av_packet_from_data(out, s->b_frame_buf, s->b_frame_buf_size);
if (ret < 0) {
goto fail;
}
if (in->size <= MAX_NVOP_SIZE) {
/* N-VOP */
av_log(ctx, AV_LOG_DEBUG, "Skipping N-VOP.\n");
s->b_frame_buf = NULL;
s->b_frame_buf_size = 0;
} else {
/* copy packet into BSFContext */
s->b_frame_buf_size = in->size;
s->b_frame_buf = create_new_buffer(in->data, in->size);
if (!s->b_frame_buf) {
s->b_frame_buf_size = 0;
ret = AVERROR(ENOMEM);
goto fail;
}
av_packet_move_ref(s->b_frame, in);
}
} else if (nb_vop >= 2) {
/* use first frame of the packet */
@ -171,6 +147,12 @@ fail:
static int mpeg4_unpack_bframes_init(AVBSFContext *ctx)
{
UnpackBFramesBSFContext *s = ctx->priv_data;
s->b_frame = av_packet_alloc();
if (!s->b_frame)
return AVERROR(ENOMEM);
if (ctx->par_in->extradata) {
int pos_p_ext = -1;
scan_buffer(ctx->par_in->extradata, ctx->par_in->extradata_size, &pos_p_ext, NULL, NULL);
@ -187,7 +169,7 @@ static int mpeg4_unpack_bframes_init(AVBSFContext *ctx)
static void mpeg4_unpack_bframes_close(AVBSFContext *bsfc)
{
UnpackBFramesBSFContext *ctx = bsfc->priv_data;
av_freep(&ctx->b_frame_buf);
av_packet_free(&ctx->b_frame);
}
static const enum AVCodecID codec_ids[] = {