---
libavcodec/webp_parser.c | 130 +++++++++++++++++++++++++++------------
1 file changed, 89 insertions(+), 41 deletions(-)
diff --git a/libavcodec/webp_parser.c b/libavcodec/webp_parser.c
index bd5f94dac5..da853bb1f5 100644
--- a/libavcodec/webp_parser.c
+++ b/libavcodec/webp_parser.c
@@ -25,13 +25,17 @@
#include "libavutil/bswap.h"
#include "libavutil/common.h"
+#include "libavutil/intreadwrite.h"
#include "parser.h"
typedef struct WebPParseContext {
ParseContext pc;
+ int frame;
+ int first_frame;
uint32_t fsize;
- uint32_t remaining_size;
+ uint32_t remaining_file_size;
+ uint32_t remaining_tag_size;
} WebPParseContext;
static int webp_parse(AVCodecParserContext *s, AVCodecContext *avctx,
@@ -41,62 +45,106 @@ static int webp_parse(AVCodecParserContext *s,
AVCodecContext *avctx,
WebPParseContext *ctx = s->priv_data;
uint64_t state = ctx->pc.state64;
int next = END_NOT_FOUND;
- int i = 0;
+ int i, len;
- *poutbuf = NULL;
- *poutbuf_size = 0;
-
-restart:
- if (ctx->pc.frame_start_found <= 8) {
- for (; i < buf_size; i++) {
+ for (i = 0; i < buf_size;) {
+ if (ctx->remaining_tag_size) {
+ /* consuming tag */
+ len = FFMIN(ctx->remaining_tag_size, buf_size - i);
+ i += len;
+ ctx->remaining_tag_size -= len;
+ ctx->remaining_file_size -= len;
+ } else {
+ /* scan for the next tag or file */
state = (state << 8) | buf[i];
- if (ctx->pc.frame_start_found == 0) {
- if ((state >> 32) == MKBETAG('R', 'I', 'F', 'F')) {
- ctx->fsize = av_bswap32(state);
- if (ctx->fsize > 15 && ctx->fsize <= UINT32_MAX - 10) {
- ctx->pc.frame_start_found = 1;
- ctx->fsize += 8;
+ i++;
+
+ if (!ctx->remaining_file_size) {
+ /* scan for the next file */
+ if (ctx->pc.frame_start_found == 4) {
+ ctx->pc.frame_start_found = 0;
+ if ((uint32_t) state == MKBETAG('W', 'E', 'B', 'P')) {
+ if (ctx->frame || i != 12) {
+ ctx->frame = 0;
+ next = i - 12;
+ state = 0;
+ ctx->pc.frame_start_found = 0;
+ break;
+ }
+ ctx->remaining_file_size = ctx->fsize - 4;
+ ctx->first_frame = 1;
+ continue;
}
}
- } else if (ctx->pc.frame_start_found == 8) {
- if ((state >> 32) != MKBETAG('W', 'E', 'B', 'P')) {
+ if (ctx->pc.frame_start_found == 0) {
+ if ((state >> 32) == MKBETAG('R', 'I', 'F', 'F')) {
+ ctx->fsize = av_bswap32(state);
+ if (ctx->fsize > 15 && ctx->fsize <= UINT32_MAX - 10) {
+ ctx->fsize += (ctx->fsize & 1);
+ ctx->pc.frame_start_found = 1;
+ }
+ }
+ } else
+ ctx->pc.frame_start_found++;
+ } else {
+ /* read the next tag */
+ ctx->remaining_file_size--;
+ if (ctx->remaining_file_size == 0) {
ctx->pc.frame_start_found = 0;
continue;
}
ctx->pc.frame_start_found++;
- ctx->remaining_size = ctx->fsize + i - 15;
- if (ctx->pc.index + i > 15) {
- next = i - 15;
- state = 0;
+ if (ctx->pc.frame_start_found < 8)
+ continue;
+
+ switch (state >> 32) {
+ case MKBETAG('A', 'N', 'M', 'F'):
+ case MKBETAG('V', 'P', '8', ' '):
+ case MKBETAG('V', 'P', '8', 'L'):
+ if (ctx->frame) {
+ ctx->frame = 0;
+ next = i - 8;
+ state = 0;
+ ctx->pc.frame_start_found = 0;
+ goto flush;
+ }
+ ctx->frame = 1;
+ break;
+ default:
break;
- } else {
- ctx->pc.state64 = 0;
- goto restart;
}
- } else if (ctx->pc.frame_start_found)
- ctx->pc.frame_start_found++;
- }
- ctx->pc.state64 = state;
- } else {
- if (ctx->remaining_size) {
- i = FFMIN(ctx->remaining_size, buf_size);
- ctx->remaining_size -= i;
- if (ctx->remaining_size)
- goto flush;
- ctx->pc.frame_start_found = 0;
- goto restart;
+ ctx->remaining_tag_size = av_bswap32(state);
+ ctx->remaining_tag_size += ctx->remaining_tag_size & 1;
+ if (ctx->remaining_tag_size > ctx->remaining_file_size) {
+ /* this might be truncated remains before end of file */
+ ctx->remaining_tag_size = ctx->remaining_file_size;
+ }
+ ctx->pc.frame_start_found = 0;
+ state = 0;
+ }
}
}
-
flush:
- if (ff_combine_frame(&ctx->pc, next, &buf, &buf_size) < 0)
+ ctx->pc.state64 = state;
+
+ if (ff_combine_frame(&ctx->pc, next, &buf, &buf_size) < 0) {
+ *poutbuf = NULL;
+ *poutbuf_size = 0;
return buf_size;
+ }
- if (next != END_NOT_FOUND && next < 0)
- ctx->pc.frame_start_found = FFMAX(ctx->pc.frame_start_found - i - 1,
0);
- else
- ctx->pc.frame_start_found = 0;
+ // Extremely simplified key frame detection:
+ // - the first frame (containing headers) is marked as a key frame
+ // - other frames are marked as non-key frames
+ if (ctx->first_frame) {
+ ctx->first_frame = 0;
+ s->pict_type = AV_PICTURE_TYPE_I;
+ s->key_frame = 1;
+ } else {
+ s->pict_type = AV_PICTURE_TYPE_P;
+ s->key_frame = 0;
+ }
*poutbuf = buf;
*poutbuf_size = buf_size;
--
2.37.1 (Apple Git-137.1)
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