On 4/23/2025 5:45 PM, Mark Thompson wrote:
+static int apv_read_header(AVFormatContext *s)
+{
+ AVStream *st;
+ GetByteContext gbc;
+ APVHeaderInfo header;
+ uint8_t buffer[28];
+ uint32_t au_size, signature, pbu_size;
+ int err, size;
+
+ err = ffio_ensure_seekback(s->pb, sizeof(buffer));
Isn't 28 bytes small enough that a backwards avio_seek() should always succeed?
+ if (err < 0)
+ return err;
+ size = avio_read(s->pb, buffer, sizeof(buffer));
+ if (size < 0)
+ return size;
+
+ bytestream2_init(&gbc, buffer, sizeof(buffer));
+
+ au_size = bytestream2_get_be32(&gbc);
+ if (au_size < 24) {
+ // Too small.
+ return AVERROR_INVALIDDATA;
+ }
+ signature = bytestream2_get_be32(&gbc);
+ if (signature != APV_SIGNATURE) {
+ // Signature is mandatory.
+ return AVERROR_INVALIDDATA;
+ }
+ pbu_size = bytestream2_get_be32(&gbc);
+ if (pbu_size < 16) {
+ // Too small.
+ return AVERROR_INVALIDDATA;
+ }
+
+ err = apv_extract_header_info(&header, &gbc);
+ if (err < 0)
+ return err;
+
+ st = avformat_new_stream(s, NULL);
+ if (!st)
+ return AVERROR(ENOMEM);
+
+ st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
+ st->codecpar->codec_id = AV_CODEC_ID_APV;
+ st->codecpar->format = header.pixel_format;
+ st->codecpar->profile = header.profile_idc;
+ st->codecpar->level = header.level_idc;
+ st->codecpar->width = header.frame_width;
+ st->codecpar->height = header.frame_height;
+
+ st->avg_frame_rate = (AVRational){ 30, 1 };
+ avpriv_set_pts_info(st, 64, 1, 30);
+
+ avio_seek(s->pb, -size, SEEK_CUR);
+
+ return 0;
+}
+
+static int apv_read_packet(AVFormatContext *s, AVPacket *pkt)
+{
+ uint32_t au_size;
+ int ret;
+
+ au_size = avio_rb32(s->pb);
+ if (au_size == 0 && avio_feof(s->pb))
+ return AVERROR_EOF;
+ if (au_size < 16 || au_size > 1 << 24) {
Might be a good idea to also check for the signature.
+ av_log(s, AV_LOG_ERROR, "APV AU is bad\n"); + return AVERROR_INVALIDDATA; + } + + ret = av_get_packet(s->pb, pkt, au_size); + pkt->flags = AV_PKT_FLAG_KEY; + + return ret; +}
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