On Wed, Apr 13, 2022 at 1:40 PM Vignesh Venkatasubramanian
<vigneshv-at-google....@ffmpeg.org> wrote:
>
> Add an AVIF muxer by re-using the existing the mov/mp4 muxer.
>
> AVIF Specification: https://aomediacodec.github.io/av1-avif
>
> Sample usage for still image:
> ffmpeg -i image.png -c:v libaom-av1 -avif-image 1 image.avif
>
> Sample usage for animated AVIF image:
> ffmpeg -i video.mp4 animated.avif
>
> We can re-use any of the AV1 encoding options that will make
> sense for image encoding (like bitrate, tiles, encoding speed,
> etc).
>
> The files generated by this muxer has been verified to be valid
> AVIF files by the following:
> 1) Displays on Chrome (both still and animated images).
> 2) Displays on Firefox (only still images, firefox does not support
> animated AVIF yet).
> 3) Verified to be valid by Compliance Warden:
> https://github.com/gpac/ComplianceWarden
>
> Fixes the encoder/muxer part of Trac Ticket #7621
>
> Signed-off-by: Vignesh Venkatasubramanian <vigne...@google.com>
> ---
> configure | 1 +
> libavformat/allformats.c | 1 +
> libavformat/movenc.c | 337 ++++++++++++++++++++++++++++++++++++---
> libavformat/movenc.h | 5 +
> 4 files changed, 319 insertions(+), 25 deletions(-)
>
It would be good to have a Changelog entry after the ticket is fixed.
> [...]
> @@ -2823,7 +2848,10 @@ static int mov_write_hdlr_tag(AVFormatContext *s,
> AVIOContext *pb, MOVTrack *tra
>
> if (track) {
> hdlr = (track->mode == MODE_MOV) ? "mhlr" : "\0\0\0\0";
> - if (track->par->codec_type == AVMEDIA_TYPE_VIDEO) {
> + if (track->mode == MODE_AVIF) {
> + hdlr_type = "pict";
> + descr = "ffmpeg";
Should this be PictureHandler or blank? What's written for heic?
> [...]
> +static int mov_write_ispe_tag(AVIOContext *pb, MOVMuxContext *mov,
> AVFormatContext *s)
> +{
> + int64_t pos = avio_tell(pb);
> + avio_wb32(pb, 0); /* size */
> + ffio_wfourcc(pb, "ispe");
> + avio_wb32(pb, 0); /* Version & flags */
> + avio_wb32(pb, s->streams[0]->codecpar->width); /* image_width */
> + avio_wb32(pb, s->streams[0]->codecpar->height); /* image_height */
> + return update_size(pb, pos);
> +}
> +
> +
This extra line could be removed.
> [...]
> + /* AVIF output must have exactly one video stream */
> + if (mov->mode == MODE_AVIF) {
> + if (s->nb_streams > 1) {
> + av_log(s, AV_LOG_ERROR, "AVIF output requires exactly one
> stream\n");
> + return AVERROR(EINVAL);
> + }
> + if (s->streams[0]->codecpar->codec_type != AVMEDIA_TYPE_VIDEO) {
> + av_log(s, AV_LOG_ERROR, "AVIF output requires one video
> stream\n");
> + return AVERROR(EINVAL);
> + }
> + }
> +
> +
This one too.
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